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Fertilizer Program - Containerized Plants (Long Post)

Posted by tapla z5b-6a MI (My Page) on
Tue, Oct 23, 07 at 20:21

This subject has been discussed frequently, but in piecemeal fashion on the Container Gardening and other forums related. Prompted by a question about fertilizers in another's post, I decided to collect a few thoughts & present my personal overview.

Fertilizer Program - Containerized Plants

Let me begin with a brief and hopefully not too technical explanation of how plants absorb water from the soil and the nutrients/solutes that are dissolved in that water. Most of us remember from our biology classes that cells have membranes that are semi-permeable. That is, they allow some things to pass through the walls, like water and whatever is dissolved in it, while excluding other materials. Osmosis is a natural phenomenon that creates a balance (isotonicity) in pressure between liquids and solutes inside and outside the cell. Water and ionic solutes will pass in and out of cell walls until an equilibrium is reached and the level of solutes in the water surrounding the cell is the same as the level of solutes in the cell.

This process begins when the finest roots absorb water molecule by molecule at the cellular level from the surface of soil particles and transport it, along with its nutrient load, throughout the plant. I want to keep this simple, so Ill just say that the best water absorption occurs when the level of solutes in soil water is lowest, and in the presence of good amounts of oxygen (this is where I get to plug a well-aerated and free-draining soil), ;o) but of course, when the level of solutes is very low, the plant is shorted the building materials (nutrients) it needs to manufacture food and keep its metabolism running smoothly, so it begins to exhibit deficiency symptoms.

We already learned that if the dissolved solutes in soil water are low, the plant may be well hydrated, but starving; however, if they are too high, the plant may have a large store of nutrients in the soil, but because of osmotic pressure, the plant may be unable to absorb the water and could die of thirst in a sea of plenty. When this condition occurs, and is severe enough (high concentrations of solutes in soil water), it causes fertilizer burn (plasmolysis), where plasma is torn from cell walls as the water inside the cell exits to maintain solute equilibrium with the water surrounding the cell.

Our job, because you will not find a sufficient supply of nutrients in a container soil, is to provide a solution of dissolved nutrients that affords the plant a supply in the adequate to luxury range, yet still makes it easy for the plant to take up enough water to be well-hydrated and free of drought stress. Electrical conductivity (EC) of the water in the soil is a reliable way to judge the level of solutes and the plants ability to take up water. There are meters that measure this conductivity, and for most plants the ideal range of conductivity is from 1.5 - 3.5 mS, with some, like tomatoes, being as high as 4.5 mS. This is more technical than I wanted to be, but I added it in case someone wanted to search "mS" or "EC". Most of us, including me, will have to be satisfied with simply guessing, but understanding how plants take up water and fertilizer and the effect of solute concentrations in soil water is an important piece of the fertilizing puzzle.

Now, some disconcerting news - you have listened to all this talk about nutrient concentrations, but what do we supply, when, and how do we supply them? We have to decide what nutrients are appropriate to add to our supplementation program, but how? Most of us are just hobby growers and cannot do tissue analysis to determine what is lacking. We can be observant and learn the symptoms of various nutrient deficiencies though - and we CAN make some surprising generalizations.

What if I said that the nutritional needs of all plants is basically the same and that one fertilizer could suit almost all the plants we grow in containers - that by increasing/decreasing the dosage as we water, we could even manipulate plants to bloom and fruit more abundantly? Its really quite logical, so please let me explain.

Tissue analysis of plants will nearly always show NPK to be in the ratio of approximately 10:1.5:7. If we assign N the constant of 100, P and K will range from 13-19 and 45-70 respectively. Ill try to remember to make a chart showing the relative ratios of all the other 13 essential nutrients that dont come from the air at the end of what I write.

All we need to do is supply nutrients in approximately the same ratio as plants use them, and in adequate amounts to keep them in the adequate to luxury range at all times. Remember that we can maximize water uptake by keeping the concentrations of solutes low, so a continual supply of a weak solution is best. Nutrients dont just suddenly appear in large quantities in nature, so the low and continual dose method most closely mimics the nutritional supply Mother Nature offers. If you decide to adopt a "fertilize every time you water" approach, most liquid fertilizers can be applied at to 1 tsp per gallon for best results. If you decide thats too much work, try halving the dose recommended & cutting the interval in half. You can work out the math for granular soluble fertilizers and apply at a similar rate.

The system is rather self regulating if fertilizer is applied in low concentrations each time you water, even with houseplants in winter. As the plants growth slows, so does its need for both water and nutrients. Larger plants and plants that are growing robustly will need more water and nutrients, so linking nutrient supply to the water supply is a win/win situation all around.

Another advantage to supplying a continual low concentration of fertilizer is it eliminates the tendency of plants to show symptoms of nutrient deficiencies after they have received high doses of fertilizer and then been allowed to return to a more favorable level of soil solute concentrations. Even at perfectly acceptable concentrations of nutrients in the soil, plants previously exposed to high concentrations of fertilizer readily display these symptoms.

You will still need to guard against watering in sips and that habits accompanying tendency to allow solute (salt) accumulation in soils. Remember that as salts accumulate, both water and nutrient uptake is made more difficult and finally impaired or made impossible in severe cases. Your soils should always allow you to water so that at least 10-15% of the total volume of water applied passes through the soil and out the drain hole to be discarded. This flushes the soil and carries accumulating solutes out the drain hole.

I have recently switched to a liquid fertilizer with micronutrients in a 12:4:8 NPK ratio. Note how close this fits the average ratio of NPK content in plant tissues, noted above (10:1.5:7). If the P looks a little high at 4, consider that in container soils, P begins to be more tightly held as pH goes from 6.5 to below 6.0, which is on the high side of most container soils pH, so the manufacturer probably gave this some careful consideration.

To answer the inevitable questions about specialty fertilizers and "special" plant nutritional requirements, let me repeat that plants need nutrients in roughly the same ratio. Ratio is an entirely a separate consideration from dosage. Youll need to adjust the dosage to fit the plant and perhaps strike a happy medium in containers that have a diversity of material.

If nutrient availability is unbalanced, if plants are getting more than they need of certain nutrients, but less than they need of others, the nutrient they need the most will be the one that limits growth. Whatever nutrients are available in excess, will be absorbed by the plant to a certain degree, and in some cases, this may lead to toxicity or even symptoms of shortages of other nutrients as toxicity levels block a plant's ability to take up other nutrients. Too much nitrogen will lead to excessive foliage production and less flowering. Too much potassium or phosphorus will not lead to ill effect, but will show up as a deficiency of other nutrients as it blocks uptake.

What about the "Bloom Booster" fertilizers you might ask? To induce more prolific flowering, a reduced N supply will have more and better effect than the high P bloom formulas. When N is reduced, it slows vegetative growth without reducing photosynthesis. Since vegetative growth is limited by a lack of N, and the photosynthetic machinery continues to turn out food, it leaves an expendable surplus for the plant to spend on flowers and fruit.

The fact that different species of plants grow in different types of soil where they are naturally found, does not mean that one needs more of a certain nutrient than the other. It just means that the plants have developed strategies to adapt to certain conditions, like excesses and deficiencies of particular nutrients..

Plants that "love" acid soils, e.g., have simply developed strategies to cope with those soils. Their calcium needs are still the same as any other plant and no different from the nutrient requirements of plants that thrive in alkaline soils. The problem for acid-loving plants is that they are unable to adequately limit their calcium uptake, and will absorb too much of it when available, resulting in cellular pH-values that are too high. Some acid-loving plants also have difficulties absorbing Fe, Mn, Cu, or Zn, which is more tightly held in alkaline soils, another reason why they thrive in low pH (acid) soils.

The point Im trying to make in the last three or four paragraphs is simply that nearly all the variables in a fertilizer regimen pertain to the plants ability to handle nutrients, not to the actual nutrient needs of the plant.

So, If you select a fertilizer that is close in ratio to the concentration of major elements in plant tissues, youre going to be in pretty good shape. Whether the fertilizer is furnished in chemical or organic form matters not a whit to the plant. Ions are ions, but there is one consideration. Chemical fertilizers are available for immediate uptake while organic fertilizers must be acted on by passing through the gut of micro-organisms to break them down into usable elemental form. Since microorganism populations are affected by cultural conditions like moisture/air levels in the soil, soil pH, fertility levels, temperature, etc., they tend to follow a boom/bust cycle in container culture, which has an impact on the reliability and timing of delivery of nutrients supplied in organic form.

What am I using? I start with a quart of 12-4-8 liquid Miracle-Gro all purpose plant food. To that, I add 3 Tbsp. of Epsom salts, 2 Tbsp. STEM (Soluble Trace Element Mix), and 1 Tbsp Sprint 138 Fe chelate and agitate until the concentrate is dissolved. I then try to fertilize my plants weakly (pun intended) with a half recommended dose of the concentrate and a little added 5-1-1 fish emulsion. The fish emulsion is for no particular reason except that I have lots of it on hand. This year my display containers performed better than they ever have in years past & they were still all looking amazingly attractive this third week of Oct when I finally decided to dismantle them because of imminent cold weather. I attribute results primarily to a good soil and a healthy nutrient supplementation program.

What would I recommend to someone who asked, for nearly all container plantings? If you can find it, a 12-4-8 liquid blend that contains all the minor elements would a great find and easy to use, but I dont think its available. What Im using does not have all the minors but I supply them with the STEM. Youll likely find a 24-8-16 product readily available in granular, soluble form with all the minors, which is the same ratio as 12-4-8, so if I had to pick one fertilizer for use on all my plants, it would be that.

The chart I promised:

I gave Nitrogen, because it's the largest nutrient component, the value of 100. Other nutrients are listed as a weight percentage of N.
N 100
P 13-19
K 45-80
S 6-9
Mg 5-15
Ca 5-15
Fe 0.7
Mn 0.4
B(oron) 0.2
Zn 0.06
Cu 0.03
Cl 0.03
M(olybden) 0.003

If you're still awake - thanks for reading. It makes me feel like the effort was worth it. ;o) Let me know what you think - please.

Al

Here is a link that might be useful: Link to Water Movement and Retention in Container Soils


Follow-Up Postings:

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RE: Fertilizer Program - Containerized Plants (Long Post)

Very nicely done, Al! You continue to amaze me with the depth of your knowledge and experience and how generously you share that with us all. Thank you. This post explained things in more detail than I have ever encountered but in a very concise, readable and understandable fashion. We should all reap the rewards with stupendous container plantings going forward!!


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RE: Fertilizer Program - Containerized Plants (Long Post)

Goodness, that *was* long. It's a good thing you didn't submit that as an answer in my other thread -- not because of the length, but because I think a topic like "Fertilizer Program" does deserve its own thread.

I have some questions on my mind, but first I'd better read it one more time :)


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Oct 23, 07 at 22:54

Ohhh thanks, Pam. You're too kind - glad we're Pals. I was wondering how it would be received, & I'm glad to learn you enjoyed it. You're qualified to spot any anomalies - see any? ;o)

Ask away, EC. Can't promise that I'll be able to answer them all, but if I can't tell you off the top of my head, I'll enjoy the challenge of finding the answer, because inevitably, I learn more than the answer I was hunting for. ;o)

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

I like the overall approach to your feeding program Al. A kudo to a well phrased and easy to understand format.

I would like to add a thought or two on the subject if I may and that is the confusion sometimes as to major, secondary and minor nutrients. Also their relationships to each other and why the most deficient one becomes the limiting factor.

Nitrogen, Phosphorus and Potassium being major nurtients by the shear need in plants of the volume of each of these elements needed for proper growth.

Sulpher, Magnesium and Calicium are next is by volume needed and the rest of the metals (mostly) being minors. AKA iron, zinc, magnanese, boron, etc. Needed as much as nitrogen just in much smaller quantities.

The challenge then becomes how to achieve balance of these in your solutions. Magnesium and Calcium being an important ratio to try to keep balanced at about 2 to 1 magnesium to calcium. Often these are two elements missing in most consumer available ferts. Hence the use of epsom salts (magnesium sulphate). Dolomitic lime is also another source of both calcium and magnesium but in a fairly slow releasing form (good for slow releasing in containers or ground applications).

I have alkaline soil and water here in Texas so often I get ample supplies of calcium but still in containers I mix gypsum into my potting media and then add epsom salts because it is often not in most soluable ferts or not in adequate amounts. Strong cell walls and deep green leaves which provide good photosynthesis and resistance to pests, drought-heat-cold stress are all benefits of working to keep a healthy balance of these to secondary nutrients.

The reliance of (bloom) high phosphorus ferts for blooming and fruiting can create imbalances with iron and create weakening of cell walls and ultimately iron chlorosis which is for any of you old enough to have seen the old geritol commercials iron poor blood and a run down sluggish feeling which lead to poor foliage, flower and/or fruit production. So again thinking a phosphorus fert will provide abundant blooms can be a flawed approach if not kept within a range of balance to other nutrients.

Too much nitrogen leads to all kinds of potential problems as much as too little does. Luxury or over-consumption leads to thin cell walls and the openess to infections, fungal or viral, insects attack and are attracted to these weakened plants creating more potential problems.

SO I am not at all disagreeing but rather am trying to help reinforce the need for balance in fertilizer used as well as how much and how frequent you use them.

I am I hope like Al trying to share some hard lessons learned over years of practicing and trying various formulas and combinations to help the plants in my care to thrive and not be pest or disease prone.

Lastly I would add the seaweed has been a great equalizer for me and helped me keep lacking minor (micro) nutrients available when my other ferts didn't have the extras needed to keep a better balance going. And I would add is often the ticket to better foliage, blooming and/ or fruit than (bloom food)phosphorus in most cases.
Happy Growing y'all David


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RE: Fertilizer Program - Containerized Plants (Long Post)

Thanks for taking the time to type all that out. I think it's a very informative, concise primer especially to plant nutrient/water absorption. I definitely learned a few things - now I know why fertilizers "burn" and how water intake is strongly dependant upon solute concentrations. OK, my questions:

1. How does foliar fertilization fit into the picture? Is it really as efficient as some sources like to claim, and are micronutrients absorbed readily through foliage? If so, then perhaps it would be possible to provide plants with a foliar nutrient boost (if required) while maintaining a low-concentration nutrient solution to the roots.

2. "If you decide thats too much work, try halving the dose recommended & cutting the interval in half."
Maybe I'm misunderstanding this, but did you mean double the dose recommended and double the interval? Or would that amount to a spike overdose?

3. Is there some sort of "minimum threshold" for nutrient concentrations below which they are less effective even when applied more regularly?
4. Should self-watering containers be avoided when using synthetic fertilizers since it would presumably be harder to flush salt deposits out of the resevoir?

5. In liquid organic fertilizers, is a significant amount of the nutrients readily available to the plant without requiring the action of soil microbes?

6. How do I amend containers for calcium and is it possible to do so without using some sort of lime which will increase the pH (or is that a good thing)?

Sorry, I don't mean to hijack your thread, but there are no Master Gardener programs where I live :)


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Oct 24, 07 at 1:10

Hi, Dave. Thanks for the contribution, I see nothing I can't agree with either. Most of the points you made that I didn't touch on, you'll find me agreeing with you in replies I've made at one point or another in the Container Soils post I linked to at the bottom of the original post here. I just didn't think I should have made my original post any longer. I figured that it would at least open the door and get some questions about specific cause/effect situations flying around.

I may not totally agree with your take on the luxury consumption in that I don't necessarily equate luxury consumption or luxury levels of nutrients in the media with over-consumption, though I do agree with your point about overconsumption.

Where you use seaweed, I'm using Micromax initially in the original soil and as deficiency symptoms appear, I supplement with STEM. Same end - different route.

Also used to believe in the high P blends for fruit/flowers, but no longer follow that line of thinking - good to see you concur.

Thanks again for the contribution. Take care

Al


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RE: Fertilizer Program--Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Oct 24, 07 at 1:52

Hi, EC - Glad you're back. ;o)

1. How does foliar fertilization fit into the picture? Is it really as efficient as some sources like to claim, and are micronutrients absorbed readily through foliage? If so, then perhaps it would be possible to provide plants with a foliar nutrient boost (if required) while maintaining a low-concentration nutrient solution to the roots.

It varies widely by plant and leaf characteristics. Water & its accompanying solutes are transported through the cuticle or epidermal cells of some leaves & twigs by diffusion, where it is adsorbed on the surface of plasmalemma (a kind of protoplasm that forms cell walls) where, by osmosis, it passes through cell membranes to cytoplasm. In some plants, water is taken in through open stomata. How much water can be absorbed through leaf & twig tissues varies by species, & within species, cultural conditions have great influence. Ambient temperature, relative humidity, leaf senescence (age), light intensity, nutritional status of the plant all have impact on how readily water is taken in through leaves & twigs. Using a surfactant (wetting agent) also facilitates diffusion. The primary factor creating a barrier to diffusion through leaf cuticle tissues is the amount of (epi)cuticular wax present in epidermal tissues.

2. "If you decide thats too much work, try halving the dose recommended & cutting the interval in half."
Maybe I'm misunderstanding this, but did you mean double the dose recommended and double the interval? Or would that amount to a spike overdose?

Halving the dose and the interval between doses keeps a lower concentration of fertilizer in the rootzone and lessens the spike, as you note, of the full strength application at suggested interval. Remember too, it also makes it easier for the plant to take up water and dissolved nutrients & remain fully hydrated.

3. Is there some sort of "minimum threshold" for nutrient concentrations below which they are less effective even when applied more regularly?

Well, you need to keep the right mix/ratio of nutrients available for uptake and in a concentration that prevents any deficiencies if you wish to maximize growth and vitality, so I would have to say there is. It's kind of a hard question to answer, because to test it, you would have to know the total dissolved solids and the proportions to determine if there was a deficiency. Any time the plant is unable to absorb sufficient nutrients, individually or collectively, to grow to its potential genetic vigor, we would have to say the plant is operating below that threshold and is in a deficiency status.

4. Should self-watering containers be avoided when using synthetic fertilizers since it would presumably be harder to flush salt deposits out of the reservoir?

Well (gulp) ;o) That's why I don't use them. The convenience isn't that important to me. I feel the design will give me problems I can eliminate by minimal additional watering efforts. I water some 200 plantings every day in summer & a little less than half that in winter, so a few extra containers here & there doesn't bother me.

5. In liquid organic fertilizers, is a significant amount of the nutrients readily available to the plant without requiring the action of soil microbes?

Unless they were added to the fertilizer in elemental form - no. If elements are locked in hydrocarbon chains, it takes the bugs to break the chains.

6. How do I amend containers for calcium and is it possible to do so without using some sort of lime which will increase the pH (or is that a good thing)?

The two most common ways are by adding gypsum or dolomitic lime. The gypsum also adds S, which is often deficient in container soils, and without affecting pH, while the dolomite adds Mg along with the Ca. I couldn't make a recommendation because I have no idea what you might be growing in over there, or what the pH of your irrigation water is. Ideal soil solute pH will be between 5.5 to 6.5. I never worry much about it, but everything seems to do well for me.

I hope all does well for you too, EC, and I hope that helped a little.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Thanks for the reply, Al.

During lunch, I was thinking about what you mentioned regarding Bloom Booster fertilizers. You said that it is preferable to reduce nitrogen instead of increasing phosphorus to promote flowering. However, for plants such as zinnias which flower continuously on side branches, wouldn't a reduction in nitrogen have an indirect effect on their development and future blooms? In this case would some addition phosphorus be preferable?

In response to your responses:

2. "Remember too, it also makes it easier for the plant to take up water and dissolved nutrients & remain fully hydrated."
I understand the reason behind using a more dilute concentration. But in your original post, you mentioned this with regard to reducing the amount of gardening work. So, wouldn't halving the watering interval mean *double* the work?

4. "Well (gulp) ;o) That's why I don't use them."
I sort of regret getting them, though. My reasons were (i)It's really hot here near the equator, (ii)I intended to crowd my plants due to lack of space, and (iii)Many of the better looking plastic boxes here are self-watering. Choice is pretty limited - we have only one major manufacturer. Well, I suppose I could always drill holes in the bottom.


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RE: Fertilizer Program - Containerized Plants (Long Post)

E.C. To follow up on the foliar feeding as an additional tool for optimum fertilizing. The simple fact is that various plants that have a shiny (waxy cuticle)surface will not take up efficient amounts of macro or micronutrients unless you catch the new growth cycles where by the new foliage has not developed the shiny look (waxy cuticle). A tomato on the other hand doesn't have a waxy cuticle so uptake is easier to provide throughout the life cycle. A pepper plant having a waxy cuticle would need to have it foliage feed during new leaf growth cycles to optimally uptake nutrients by foliar feeding.

Commercially citrus, avocado and pecan are foliar feed (zinc and/ or iron during these growth flushes to place the micros into the growing area.

The other challenge to foliar feeding is zinc and other micros don't translocate well (move from one part of the plant to another). Nitrogen does translocate well so can benefit all parts of the plant (if it can be absorbed by the leaf).

Micros move up from the roots during these growth cycles and if available will provide all that is needed. But water stress, heat stress, cold stress and ph all play a role in how well these nutrients are taken up as is well spoken by Al earlier in this post.

In summary I would not advocate personally the use of foliar feeding as more than an additonal tool for optimum growth needs as required and only if used at the right time and/ or for the right plants. I do foliar feed many plants as part of my fert program and consider it very useful but it needs to be understood well to get the most from its practice.

Legacy: I would love to read the material you have read about magnesium supplementation as being not useful. At least as to what context this study was performed under.
I, like all here, continue to learn and work toward doing the best we can for our plants with the most effective means possible so if you could share this I would personally welcome it for its potential to understand more about it.

Al: The use of micromax and STEM are great and will do all that you have said but they aren't readily available to many gardeners so I tend to stick more to what I can provide to my customers easily. A means to an end not a difference of opinion:).
BTW, I have had several good experiences and have gleaned a lot that I have been sharing with my customers about the potting mixes used by you through this forum and can say it has helped in most cases but watering can still be an issue during the hottest parts of summer here in Texas. (This year being an extremely wet one was very useful with the better drained mixes) and will be tweaking more going into next year. Thanks again for your sharing. You continue to affect and help more people be better growers than you may realize.
As always...
Happy Growing to all David


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RE: Fertilizer Program-container

Dear David,

RE: Epsom Salt Studies

It was a short one sentence passing remark from a cooperative extension or university associated article on a totally unrelated subject - gypsum I believe - that I was reading. There was no citation offered about the epsom salt study or studies. I will see if I can find the article I read or other corroborating sources about the finding for you.


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Oct 24, 07 at 12:50

I'm so grateful to iVillage people for cleaning up this thread - thank you!

Hi, EC You wrote:

In response to your responses:
1) "Remember too, it also makes it easier for the plant to take up water and dissolved nutrients & remain fully hydrated."
I understand the reason behind using a more dilute concentration. But in your original post, you mentioned this with regard to reducing the amount of gardening work. So, wouldn't halving the watering interval mean *double* the work?

I didn't see where I said that, but yes, it does double the work of adding fertilizer only, but that is a small chore. I suppose if you water with a hose instead of a water can, it would makes additional work. That's kind of an individual decision you need to make. I often say that grower convenience and best plant vitality are often mutually exclusive of each other. ;o)

2) "Well (gulp) ;o) That's why I don't use them."
I sort of regret getting them, though. My reasons were (i)It's really hot here near the equator, (ii)I intended to crowd my plants due to lack of space, and (iii)Many of the better looking plastic boxes here are self-watering. Choice is pretty limited - we have only one major manufacturer. Well, I suppose I could always drill holes in the bottom.

Mmmhmm. That would be my inclination, but that's just me and my personal preference. Remember too, that if you crowd the plants you could reduce air movement enough to give things fungal a toe hold.

Dave - if you're still around & have interest for your own use, I can probably put you on to a source of either STEM or Micromax at reasonable prices in small quantities. Let me know .....

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Greetings Everyone,

I didnt use one or two fertilizer formulas or a set fertilizer program but also had an improved and satisfactory year with my soilless container plants. My roses, gardenias (acid-loving), honeysuckles, ornamental scarlet runner beans, chili peppers, tomatoes, cantaloupe, leafy vegetables, and strawberries in containers also all bloomed and produced well this year (some are still around even with the recent swings in temperatures). In fact, I probably neglected them too much and have not kept up with caring or fertilizing my plants because I spent a lot of time reading and learning how to care for my flowers and plants (as much as time allowed). I then test out what I read and can confirm. I also spent some time memorizing, keeping, and analyzing records to make sure my flowers have their horticultural requirements met and to prevent diseases, such as preferred pH and fertility or lack of, both before and after I plant them.

I fertilize my plants at each watering in diluted amounts (1/2-1/8 strength), but my plants, crops, and flowers don't get the same macros and micros or in identical strength and frequency or as a regimen or scheduled program. In addition to alternating and using 5 different synthetic soluble fertilizer formulas, I also incorporated organic fertilizers such as seaweed emulsion, fish emulsion, compost tea, and I top dress with compost and coffee grounds selectively. Different flowers and plants or groups of vegetables and flowering/fruiting plants get different synthetic or organic fertilizers and concentration of liquid fertilizers at different stages of their development and rate of growth. When I see changes in leaf color, vegetative growth, or healthy of a plant as a consequence of my recent use or delivery of certain type of fertilizer, I alternate or adjust my diluted fertilizers again (in ratio, type, and strength), or I may just water and give the affected plant a rest or to leach out excess salts from the containers for the next 1.5 weeks or about 2-3 consecutive watering sequence depending on the visual changes and feedback I get from them and other observable variables such as temp change and seasonal day length, etc. I don't use one or two fertilizers or combine them to formulate a standard complete feed other than feed and water my container vegetables, plants, and flowers according to interpretive plant needs, the changing conditions I see, or any plant-specific feeding requirements I researched previously by using the 10 different sources of synthetic or organic fertilizers I have independently.

I only supplement iron chelate, calcium, trace minerals, and/or adjust the pH of my potting mix when my plants exhibit symptoms (of deficiencies) or after Ive identified them. If I see any unusual changes in the leaves and plants, I look up any images and relevant nutritional deficiencies documented for the plant. I then choose and prioritize my remedial options after I analyze the top 3 most probable cause(s) or nutritional imbalance.

I use a balanced slow-release fertilizer in the potting mix, and I don't use high nitrogen synthetic soluble fertilizer in containers. The only high nitrogen synthetic liquid fertilizers I have is formulated for acid-loving plant which I use on my potted Gardenias at times.

I make my own compost and seaweed emulsion for needed trace minerals. I also use epsom salt at times but recently read that the added magnesium did not show to improve plant growth in studies. However, I have yet had the time to corroborate the finding.

The only fertilizer issue I would like to improve on would be to investigate ways to improve my current small anaerobic composting operation (3 rotating bins) to turn out finished compost faster for my small balcony garden, but it's performance is sufficient for now and not a priority given the items still on my priority to-do list.


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RE: Fertilizer Program - Containerized Plants (Long Post)

Hi Al,

2) Was just splitting hairs with you....my bad :P
I'm the sort of gardener who would brave a thunderstorm to stake my swaying plants, so I'm not going to complain about having to do a little extra fertilizing.

4) Don't jinx it! hahaa. Yeah, I packed them so closely, and the weather has been so wet that I'm quite surprised they haven't flopped over and died from fungal diseases....yet.


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RE: Fertilizer Program - Containerized Plants (Long Post)

Interesting topic, and very nicely laid out, Al. Thanks for all the hard work.

I am wandering over from the Orchids forum, where quite a bit of time is spent chewing over fertilization. We're probably a more obsessed bunch than most gardeners, since most orchids are grown potted in nutrient poor/free media or mounted on cork/sticks, etc, so the what the grower supplies externally is what the plant gets.

A current popular fertilizing scheme is the so-called Michigan State University formula, developed by (I think) Bill Argo. There are a couple of different commericial suppliers of this formula, which all consist of about:

12 N : 2.5 P : 14 K : 8 Ca : 2 Mg : 0.166 Fe : 0.08 Mn : 0.04 Zn : 0.04 Cu : 0.02 B : 0.02 Mo

which is a reasonable match for the formula Al presented.

Second point I'd like to make is about the minerals present in your water supply, which varies greatly with your area. For example, the metro Boston area where I am has very clean water with around 5 parts per million (ppm) of calcium and <1 ppm magnesium. Thus, I have to supplement these minerals. Other areas, and Florida and Texas come to mind, with "hard" well water, might have 10 times the amount of Ca and Mg in their water and would have no need to add them. You can find out this information by asking or googling for a water-quality analysis from your water authority. The best US water will have a total-dissolved-solids (TDS) measure of less than 100 ppm, some places <50. "Hard" water might have TDS >500 ppm. Many orchid growers in these areas have their own home reverse-osmosis system to purify their tap water for watering their plants, as orchids tend to be very sensitive to high mineral content.

Last point is that Al's recommendation on frequent, dilute feeding matches the orchid grower's mantra of fertilizing "weekly, weakly". I aim for about 100 ppm of nitrogen each time I am adding fertilizer.

Al, thanks again for post. It's a keeper.


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Oct 24, 07 at 17:12

Ohh - thanks for the nice comments, Tee - they're appreciated, and it's good to learn it caught your eye and is in keeping with your thinking.

I know what you mean about the tap water. I grow several terrestrials in containers and we have a pretty high pH and TDS, so I really need to use a very fast soil, enabling me to flush thoroughly at every watering, lest I get into trouble with carbonate accumulations.

Thanks for visiting.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

I should never post late at night as I am prone to have dyxlectic tendencies. The ratio stated on Ca (calcium) to Mg (magnseium) is 2 to 1 Ca to Mg. My bad and hope this is noted for anyone that was looking at this component of your fert regime. Sorry No more late night technical posts.:)
Happy Growing David


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RE: Fertilizer Program - Containerized Plants (Long Post)

A few helpful points for fellow gardeners to consider:

1. Container gardeners sure appreciate and can learn from each other. Expert gardening tips certainly increase the efficiency and a gardeners odds of success if they are given and applied in proper context. However, many species of plants are very resilient and will also thrive in a range of plant-specific conditions. Often, many will acclimate, adopt, and thrive even in borderline ideal conditions.

2. Opinions and gardening experiences and results shared on these forums often are not and do not have to be either-or choices as some may want them to be for various personal reasons or to stifle proper inquiries or examination of the claims or suggestions presented or when other possibilities and options co-exist. Gardening successes as a result from different ways of doing things whether they are based on facts, research, anecdotes, or accidents can co-exist just like the abundance we have in life is often a mix bag of all the above and not always by planning or design. Technical know-how certainly increases the efficiency and a gardeners odds of success if they are given and applied properly with qualifying context.

3. Unless it is a technical paper one is presenting with proper references and citation, the expert tips and recommendations while helpful are still as unsubstantiated and anecdotal as an opinion or a personal experience and not necessary definitive, universally applicable, or The Way. And even if a fact or published findings and the interpretive results are substantiated and corroborated with reproducible results as well as being consistent with other related disciplines, the application of such findings are highly either condition or plant classification specific and should not be generalized without qualification or offering proper context (elucidated further in details by articles below). The usability of the presented facts should also not be overlooked.

4. If you are versed in scientific methods and reading research papers, youll find that scientists often disagree even with the same data. They often come to very different conclusions based on the methods as well as how the data are interpreted. Hence, independent non-political non commercially driven peer reviews of research papers are important in scientific inquiry and often welcome and appreciated. University funded research is not without bias because it is often commercially funded.

This is an interesting article from Ohio University about fertilizing container plants in my collection: Micronutrient Sources for Container Nursery Plants . Although I didnt completely follow all the expert opinions and findings suggested in this article, the expert opinions in this article will contradict some of the suggestions Al recommended and elucidate generally what I said above about reading and accepting expert opinions as well as the reasons why I dont supplement or amend my container plants without instrumental readings of my potting mixes with respect to the horticultural conditions, needs, and requirements of a plant or actual exhibited symptoms and some of the reasons on technical grounds that I fertilize the way I do (and share and help the way I do). This is not to say Al's way is wrong other than that other ways of fertilizing will equally or also lead to acceptable, improved, or good outcome.

Hi David,

Thanks you for supplying us with a good Ca:Mg ratio for container culture.

Here is the excerpt from University Minnesota Extension where I read epsom salt use did not show to benefit plant growth and a link is also provided.

"Some soil testing labs will report ideal calcium to magnesium ratios for plant growth. However, most plants tolerate a very wide range of soil calcium to magnesium ratios. Adjusting the ratios of calcium and magnesium on the exchange complex by adding gypsum (calcium sulfate) or Epsom salts (magnesium sulfate) has not been shown to significantly benefit plant growth. Addition of gypsum or Epsom salts may be beneficial if calcium, magnesium or sulphur are deficient in the soil." Cation Exchange Capacity

Another independent source but very old (1998) also happen to be in my collection which also suggests supplementing magnesium isnt the solution based on the results of two small soil tests and at a specified pH range: Epsom Salts

Again, I am not presenting these expert opinions or findings as substantiated facts since I didn't look at both sides of the story in depth. And contrary to the 1998 Benicia Nursery article, no context was offered in the University Minnesota article on a cursory read. The expert opinions in these two articles seem to agree, however. Given the time frame differences between the two write-ups (6 years), its likely that the limited benefits of supplementing magnesium sulfate is a well-known or proven fact in expert circles.


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RE: Fertilizer Program - Containerized Plants (Long Post)

Legacy:
Thanks for the info on epsom salts. After reading thru the material I would conjecture that
The value assigned in several of the studies were based on dry weight measures. Which are of a value to biomass but not by fruit or flower production. The other values not offered in this type of study also don't assess pest values (aka) resistance or other not.

These to me as a nurseryman and homeowner have equal values to the shear biomass values. There are so many interactions that may be asssigned values that is beyond a controlled studies scope that here in lies the downsides of these research studies.

I appreciate your offering these for all to see and feel they have values to be considered for anyone growing plants for pleasure and or profit.

Is the return on investment worth the cost of inputs I use? I would say for me thus far yes. If I have plants that people want to buy because they look good to them and that a month, year, or decade later they are still happy with then I have done what I set out to do. Offer a quality grown plant that has a happy home with someone and has made the company I work for a profit. I call this a win-win situation and it is the only kind of work I am interested in giving my life to.

I am grateful for the chance to serve my fellow man in this capacity and even though I have been at it for over 20 years now in one manner or another I still feel the need to constantly learn and improve on what I have done or that others have offered me to try so I can be better at what I do.

I am no guru or expert just a avid plant lover that likes to share what I have learned thus far for someone else to use or discard as they choose. I will never have all the answers and will spend the rest of my life searching for more answers to my questions none the less.

I will reread these links again in the morning when my brain is fresh and my mind is more receptive to little nuances that I miss when I study late at night. I used to be able to study better at the end of the day and into the night but find as I have gotten older that I do my best work of this nature after rising in the morning uncluttered with the matters of the day behind and not yet ready to think about the day ahead then I am in a state of learning and glean the gems that I continue to search for.

I have rambled on too long so to all a good night and as always Happy Growing David


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RE: Fertilizer Program - Containerized Plants (Long Post)

@hitexplanter

"....In summary I would not advocate personally the use of foliar feeding as more than an additonal tool for optimum growth needs as required and only if used at the right time and/ or for the right plants. I do foliar feed many plants as part of my fert program and consider it very useful but it needs to be understood well to get the most from its practice."

Thanks for the info about the effectiveness of foliar feeding and micronutrient mobility. I will keep that in mind the next time I'm tempted to overdo the spraying :P


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RE: Fertilizer Program - Containerized Plants (Long Post)

Hello hitexplanter, I'm not sure I understood the points you made or the significance of knowing the value of biomass. I am interested to know more about the points you are making or what I need to know to better care for my plants when you have more time.

Here are some of my observation and basic central concerns I have about advocating a way or method of fertilizing container plants (and to a lesser extent about potting mix) after all the interesting, well-meaning, technical, and theoretical discussions have been said:

1. Different ways of fertilizing as well as the use of different soilless mixes (or other growing medium) can clearly equally lead to success and improved results. I question the notation that there is an unqualifying better way or universal way to fertilize potted plants however it may be well-received and with or without objectivity on technical and applicable reasons.

2. Unless I miss the points being made, I can't think of a rational and realistic reason to have one simple or best way of fertilizing even if it may be well-meaning and well-received or supported with or without biases and proper context. I don't think our roses or crops would care in any case how well some other roses or crops are doing in some unknown regions. We can't talk of our container flowers, crops, herbs, roses, bulbs, shrubs, or fruit trees like we are maintaining our models of car or computer operating systems. Even under one regional growing condition with identical microclimate and water quality, these container plants have very different horticultural needs and requirements with respect to fertility, potting mix composition, life cycles. I simply can't pot up and fertilize my gardenia the same way I plant or care for my containerized tomatoes or wildflowers even in the same microclimate and water quality. Outside a regional growing condition and water quality with differences in microclimates and water quality, the same potted plants will have to be fertlized differently to meet their horticultural requirements because they are also subject to different growing mediums, climates, microclimates, water quality, and container amendments in reality.

3. Most home gardeners who care for many varieties of plants do not use measuring instruments to test their potting mixes. Thus, amending and fertilizing potted plants have to be a visual as well as knowledge-based soil science interplay. Supplementing micronutrients before visual symptoms of nutritional deficiency can cause nutritional imbalance. In addition, many containerized plants would have little need of supplemental micronutrients as prevention based on soil tests if you read the articles linked above, and when they also get organic amendments and emulsions.

4. If regular use of high nitrogen fertilizer use is bad for soil-based plants and for the environment, the same adverse consequences of leaching excess nitrogen would apply and may be even worse in potted plants, especially when gardeners practice the easy and sensible high fertilizer dilution at each watering method.

Happy to hear all your experiences, expertise, and thoughts.


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RE: Fertilizer Program - Containerized Plants (Long Post)

Al,

Thanx for the info you outlined above. I really appreciate the simplicity of your fertilizing regimnent (if that is the correct term). I would guess quite a few of the posters and readers here (like me) are not highly educated in plant husbandry and cannot readily descern if a plant needs a certain fertilizer or mineral or whatever, so simplifying the application of fertilizer (not to mention soil/air/watering as mentioned in your other posts) is a great help to all of us who are just starting out. There is soooo much information out there and so little time to reseach...Research is good, dont get me wrong, but I want to have nice healthy plants to enjoy while I learn. BTW, due to inexperience and bad information, I tried the high nitrogen approach to greener and better plants, high P for better blooms, seaweed, fish fertilizer, asprin, and all sorts of gimmics...trying to figure out how to get the best, greenest, most flowering plants...(sigh)...I think you hit the nail on the head here with your formula for fertilizing. For now, at least until I learn a lot more about plants and fertilizing them, watering them and keeping them happy, I think I will follow your lead. BUT...you can be sure that when I get this all figured out and become an expert master gardener I will repost and probably have much more to say...

Thanx again Al,

Tim


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RE: Fertilizer Program - Containerized Plants (Long Post)

Legacy:
I will try to cover a few of your questions or thoughts on the subject of ferting before I head to work this morn.

1. Undoubtablely there are many approaches to ferting that will lead to good growth and success with multiple or varied fertilizing regime.

Is there a standard that can be applied across the board for every plant? Simlpe answer No.
But some useful general ratios of fertiler will be workable for a great deal of plants that many folks grow. In many cases the fertilizer industry puts too much importance in P (phosphorus)IMHO. If I was to completely go by the marketing that these company tell me I would need dozens of different formulas to grow to grow the plants in the average home containered and landscape situations. I personally believe that this is a bunch of malarky to put it bluntly.

Many plants (not all) will perform very well with a 3-1-2 ratio fertilizer for the majority of it nutrient need with the addition of whatever secondary and micronutrients are lacking in this given material.

Generally speaking most fertilizers will say to feed every week or two for soluables and four to six weeks for granular. This is in large part(again my opinion) to make it easier for the average gardener to not be afraid to fertilize and not have people think they have to or could fertilize everyday in many cases and have better results.

The challenge for these companies is to encourage the use of their products regularly and with ease so people won't shy away from them because it is too complicated or too time consuming.

In almost every nursery situation I have been involved with over the last 20 years, fertigation is the standard for maintaining and growing out plants. The reasons for this are many but the two main ones are to keep it simple for workers to water the plants while weakly feeding them at the same time.

The workers don't have to know anything but how to water and yet they are feeding the plants at the same time. This is labor efficient and takes the technical aspect out of it expect for the person in charge of supplying the fertiler to the system.

Just like we as people eat everyday (at least the majority of us in America that have an abundant food supply and the means to purchase it) Plants will also do better as a general rule by this same process. Instead of a feast or famine approach we have a more even supply of nutrition being consumed (whether it is plant or human) the same principle applies. The use of SRF (slow release fertilizer) is based on this same concept and again is widely used and accepted in the nursery industry as a good baseline fertilizing regime and then is supplimented with a solualble fertilizer as needed. The additions of secondary and micronutrients are also used the same way. Some supplied up front in the potting media and additions made through fertigation or reapplied to the top of the soil if practical to the situation. Most of this is again to supply the plant with every need it will likely have during its time in the nursery and for some period of time after.
These same things can be used by the average gardener if understood how to do it but it can and is a complex science that can result in disaster if not properly applied.

The challenge to a home gardener *IMHO* is to get past all the marketing that fertilizer companies use to get you to buy their products because it is for tomato, flowers, trees or whatever. Learn to look on the back of the label and read the ingredients (N-P-K and secondary and micros) will yield better results and not have you buying 10 fertlizer packages for 10 different plants. I do guarantee there is not a grower one of multiple plant species that uses a different fertilizer for every plant type they grow and yet they produce perfectly (maybe not perfect:) but healthy sellable plants with a few base fertilizers. This not to say that everyone should do this but that is how the pros do it and it is reasonble to think that home gardeners can to if they would take some time to learn basic plant nutrition and be observant of the changes going through out the year.

I have just a few minutes left and I have been as usual too long winded and haven't gotten to many points yet.

Using supplemental secondary and micronutrients can be a blessing or a curse.
The first reason I have for making sure a plant is being supplied with them is (insurance). The second is that once you visually see an deficiency in a plant it is already not a happy camper and it is going to take extra effort to get it back to full health. This is not a good thing and will be problematic for any nursery and *IMHO* for any home gardener. Once you have a zinc or iron defiency for example you will need to know how to ID it and what to use to correct it. It is better *IMHO* to keep levels closer to optimum where practical. Both these micros being somewhat immobile except under certain conditions makes it a lot of extra effort to bring the plant back to a fully visually happy state.

Sorry out of time for today and so will stop here for now. If anyone want to read more on my thought about fert and their interaction with plants let me know and I will try to pick up where I left off or try to help with specific questions if I can.

For now Happy Growing to all David


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Sat, Oct 27, 07 at 10:25

Thanks, Dave. Nicely said.

Thank you too, Tim. It makes me happy to know you found some value in your reading - and the effort to say so is appreciated.

I know lots of people try many approaches based on misinformation or the fact that so many fertilizer manufacturers promote 'special' fertilizers for half the variety of plants we grow. They think they're doing the very best thing for their plants just because they provide their nutrients from a package specifically labled for roses or azaleas, e.g. As often as not, or even more often than not, the blend may not be as appropriate as as a 3-1-2 ratio.

The number of nonspecific ions in the soil solution determines its electrical conductivity (EC). Plants take up water and dissolved nutrients easiest when the electrical conductivity (EC) range of soil solutes is favorable, and it varies by plant, but even if we're able to maintain that favorable level of EC, we are not necessarily sure that we are supplying the proper mix of ions (nutrients). If we supply only P, for example, the EC could be in a perfect range, but P will be supplying nearly all the ions. If we try to correct by adding N and K, plus the ether essential nutrients, it raises the EC of the soil solutes and causes drought stress/starvation/deficiencies if it becomes too high.

Most greenhouse operations will follow pretty closely to a 2-1-2 ratio of the primary macro-nutrients on most greenhouse crops with minor deviations based on tissue analysis and the effect of the growing medium. Most post-greenhouse fertilization will follow fairly closely to a 3-1-2 ratio, with some deviation. Again, this very closely mimics the range of the primary macros found in plant tissues.

For those that might be confused by the concept of ratios, it's kind of like reducing fractions. 24-8-16 and 12-4-8 are both a 3-1-2 ratio fertilizer. The only difference is the 24-8-16 has twice as much NPK by weight as the 12-4-8. If we could buy 3-1-2, it would only have 1/8 the NPK of 24-8-16. The only difference in their use is the dilution rate. Both 24-8-16 and 12-4-8 are both readily available in most stores and it should be no surprise that they are usually labeled and sold as 'all purpose fertilizers'.

Back to Tim - Good luck in the Master Gardener program. It will provide you with a lot of good information, but just as important is the fact that it will help you learn where to look for info when you need it. If the core manual is anything like ours, it will also be a great source for basic information. I still refer to it when asked questions about things like sorting out the difference in how to prune different cane plants or trying to sort out all the different root types and how plants multiply via root structures. I'm straying now though - take care. ;o)

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Whether we are trying to make things complicated or simple and if anyone read and reflected on the technical references cited equally, the evidence and opinions in these sample sources in short do not entirely support what was recommended or suggested. The more interesting discussions and issues are why and how.

No worry in me being influenced by commerce or the academia. I may start with what was given, available, or taught, but a blessing or a curse is also that I will question and don't stop there. I build on what I read or heard. Maybe some of you do, too.

Commercial operations are not likely to care for potted plants from beginning to end or for longer-term as home gardeners hope to do in most cases unless the operation is a specialty grower, so one would expect the fertilizing duties involving greater number of people to be streamlined or at least coordinated to keep the efficient and sales turnover rate up and cash-flow in the positive. Though such care makes practical sense in short-term care, retail operations, or controlled greenhouse environments, these sensible and for-profit choices for retail growers don't always mean they are either good fertilizing choices for home gardeners or chosen growing conditions or that such commercial and professional practices are necessary supported or confirmed by science or evidence. On the other hand, many specialty growers and greenhouse nurseries by nature have to be technical and research oriented to be profitable.

Just to clarify one issue about my way of fertilizing since it was mentioned. While my plants do get NPK and trace minerals from ten different synthetic and organic sources or forumulas depending how they are looking to me visually and at what stage of maturity and with respect to season and sunlight, I neither follow or have a complicated fertilizer regimen, nor do I designate or use different formulas for different plants. My vegetables may get higher nitrogen ratio organic fertilizers more consistently than other pots, but my container flowers, crops, fruit trees, and plants get their macros and minors from all ten organic and low-nitrogen synthetic sources guided by plant maturity and needs, enviornmental variables, visual observation, and reading and not by a products, program, or regimen.

Gardeners often don't learn from our successes (at least not solely). We learn the most when our plants don't look their best or are in trouble (and perhaps there is no better urgency and motivation). There is no better time to learn other than now regardless of experience or knowledge.


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RE: Fertilizer Program - Containerized Plants (Long Post)

The pH of the growing medium will also affect the availability and absorption of many trace minerals; thus, the effective resolution often isn't necessary supplementing or replenishment of a lack of any trace minerals if deficiency isn't the cause and when bioavailability is the cause which can involve other variables, such as either an excess in ratio of another competing trace mineral or an issue of pH. However, the issue of acidity or alkalinity of a potting mix in most cases only need to be maintained, altered or amended in containers if you are growing plants that thrive or are sensitive in the extremes of this pH scale. Without using a measuring or reading tools for these plants, one could still care for these plants successfully by researching and preparing ahead of time and by watching the color changes, rate or growth, and visual symptoms for plant-specific nutritional deficiency.

I search the Internet and read as many articles, fact sheets and studies as much I can from local, regional, and national sources as well as from specialty nuseries and a few from master gardeners on many of the vegetables, flowers, and plants I have, and if possible I look for local technical relevant information in container culture. After I reflected and recalled a bit in general on all the cursory reading I have done and unless it's a coincidence that the varieties of my vegetables and herbs, flowers, shrubs, and plants are all exceptions, rarely do I encounter a high nitrogen or a 3:1:2 fertilizing recommendation for in ground planting and container culture from these highly credible and varied expert sources. I want to say may be two out ten and no more than one handful of times. The only memorable high nitrogen or a specific 3:1:2 fertilizer I read happen to be for acid-loving plants, and it was a specific recommendation for caring and growing gardenias which I own.


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Oct 29, 07 at 1:01

Hi, Guys. I'm weary from playing with the grandkids all afternoon, but I wanted to offer a few thoughts for your consideration.

I have a long history of posting on this forum, and I've always been able to back whatever I say with science and sound reasoning. My post on this thread is no different. I discussed this post with a botanist friend, the director of a nearby horticultural garden, and a friend who is an owner of a very large greenhouse operation before I put it together. I have more than two dozen technical texts that validate the thoughts I set forth, so I'm not concerned that my thinking is so closely scrutinized and disagreed with from one direction. In other words, I don't just pull this stuff out of the sky. ;o)

I hope you'll take a minute to look again at this chart, showing the range of nutrients found in the living tissues of almost all plants. There are many like it in several of my texts that deal with tissue analysis, and you'll find similar charts all over the net if you want to take the time to look.

I gave Nitrogen, because it's the largest nutrient component, the value of 100. Other nutrients are listed as a weight percentage of N.
N 100
P 13-19
K 45-80
S 6-9
Mg 5-15
Ca 5-15
Fe 0.7
Mn 0.4
B(oron) 0.2
Zn 0.06
Cu 0.03
Cl 0.03
M(olybden) 0.003

Simply said, this chart shows that plant tissue (I'm going to average the ranges and reduce the fractions to something like a fertilizer ratio that is easy to understand) contains NPK in approximately a ratio of 10:1.6:6.3

You can see that viable plant tissues, on average, contain about 6 times more N than P, and 1.5 times more N than K.

When commercial operations fertilize, they often use sophisticated tissue analysis to determine which of these three primary macronutrients, secondary macronutrients (magnesium, calcium, sulfur), and/or micronutrients are in tissues in excess or are deficient. When they are deficient, they will adjust the fertigation program to raise the level of that nutrient in tissues to the proper range - the opposite for excesses. If tissue analysis shows there is no deficiency or excess, all is well (unless there is intentional manipulation of nutrients to achieve a specific end - often the rule) and the blend will be very close to the 10:1.6:6.3 noted above.

I would like you to take note of how close that ratio is to a 3:1:2 ratio and that in comparison, the N level is actually comparatively LOWER in a 3:1:2 than it is in the 10:1.6:6.3 ratio found in plants. In truth, and I've already mentioned this, most greenhouse operations, because there is intentional manipulation in the young plants will start at something closer to a 2:1:2 ratio and finish with something closer to the 10:1.6:6.3 (or close to 3:1:2). Nursery plants will be fertilized fairly close to the 3:1:2 ratio as well. For clarity, finished means when the plants are ready to be hardened off & offered for sale.

Remember that we struck an average for the range of nutrients in tissues. I made no claim that all plants will have the same levels of nutrients present in tissues. If you examine the range though, you will see that moving to either extreme of the range does not significantly change the ratio - certainly not more than one point.

Some of us are fairly good at discerning symptoms of simple nutrient deficiencies, but you need to be a good detective and have a clear understanding of macro/micronutrient relationships to be even halfway accurate. Since none of us likely has the ability to analyze tissue & correct deficiencies by fine tuning our fertilizer program to the nth degree, we need to make an educated guess at at the best shotgun approach.

24-8-16 and 12-4-8 are both fertilizers in the 3:1:2 ratio. The 24-8-16 is even available from more than one supplier with all the minor elements included. This blend is often called an 'all-purpose' fertilizer for good reason, and has been around forever. It has about the closest ratio of major nutrients to what plants actually use.

For the more sophisticated growers, it may require some minor tweaking, but is still the best starting point, for my money. For those that have better ideas, by all means - use what you like. For those that wonder where to start, or what to use, the two blends listed above, or something very near the same ratio will not likely ever put you far off course. Of course, you're still charged with the same responsibility of learning your plants wants with these, as with any other nutrient supplements, but actually, that's even difficult to do unless we understand soil chemistry and it's effect on nutrition and availability of nutrients.

Look the link over for a simplified overview on the relationship of fertigation to tissue analysis. The chart shows nutrient levels of individual crops, but if you look, you'll see that the crops fall within the range of the chart I offered on nursery and greenhouse tissue nutrient content. The only point the link makes is the fact that there is a definite connection between the nutrient content of plants and the ratio of nutrients in production fertilizer regimens. Doesn't it make sense for us, as hobby growers, to try to come as close to that as we can with what we have readily available?

In this thread, I tried to offer a sensible and simple overview. I usually don't encounter so much adversity when I present an idea or view, so I guess you'll need to decide what seems logical to you. ;o)

Thanks for listening and forgive grammar/spelling mistakes. I'm tired now & will not proof what I wrote. I hope it makes sense.

I don't want to come off as too defensive or repetitive, but this point about plant nutrient content as it relates to usage/uptake is important and I want to be sure it's not missed.

Al

Here is a link that might be useful: A glimpse at tissue analysis/fertigation


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RE: Fertilizer Program - Containerized Plants (Long Post)

This forum should have a FAQ page and this original msg should be in it! Why isn't there a FAQ page?
~Tom


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Oct 29, 07 at 20:56

Thank you, Tom. The encouragement I take from your kind comment is especially appreciated on this thread.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by bjs496 9/Houston 7/NJ (My Page) on
    Tue, Oct 30, 07 at 10:56

Hi All,

I appreciate all of the insights you guys have provided in this post. What always confuses the living sh... crap out of me is how the manufactures come up with the dilution ratios for a working solution, and I guess in turn, how do I come up with a dilution ratio?

Presumably, a solution that has an NPK ratio of 7-7-7 has .07 ounces of Nitrogen per ounce of solution. If the stock solution is diluted one ounce per gallon of water to come up with a working solution, there is .0055 ounces of Nitrogen per ounce. However, the dilution rate for a given stock solution varies between manufactures. Shouldn't the "start" point for N (regardless of the final NPK ratio) be the same? If we feel (and I'm not saying this is the case, just using it as an example) that the start point for a N should be .06% of the working solution, shouldn't all of the manufactures dilution recommendations end up with a .06% N in working solution? Why don't they? Fertilizer burn occurs when the concentration in the working solution is to high, so why are there no clear guidelines on where to start (where N=100 as indicated in the charts)? I know that it will ultimately vary based on the plant, but there has to be an assumption as to where the start point is, right? UGH!

One more thing, since we are on the subject, are we supposed feed the container or the plant? A few of the slow release granule manufactures have information regarding application rates based on volume of soil in the container. I'm guessing this means they want us to feed the container. However, the size of the plant in a container of a given size can vary widely. Here is a chart derived from a Florida Grades and Standards publication:

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The caliper of a tree in a 15 gallon bucket can vary from 1 1/4 inches to 2 inches. Does a 1 1/4 inch tree in a 15 gallon container get the same amount of fertilizer as a 2 inch tree in a 15 gallon container? If one had a 1 7/8 inch tree in a 15 gallon container would it deserve less fertilizer than a 1 7/8 inch tree which had already been bumped up to a 30 gallon container? Does one adjust the dilution of the fertilizer based on the size of the tree (the container can only hold so much moisture)? or do we average it out and hope for the best?

Everything else has been easy to understand and implement... the issue of feeding has not. It is the source of great confusion and frustration for me. It makes me want to pull what's left of my hair out when I ask my neighbor what he does that his tree looks better than mine and he says "Uhhh, I don't know, it just kinda sits there."

Thanks for letting me rant,
~james


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Oct 30, 07 at 15:50

Hi, James! Haven't seen you here on the container forum much lately. Good to see you! ;o)

I'll try to answer & keep it as simple as possible. If I miss anything, don't hesitate to ask again or write.

What always confuses me, is how the manufactures come up with the dilution ratios for a working solution, and I guess in turn, how do I come up with a dilution ratio?

Manufacturers base their concentrations of ingredients in large part on marketability. An example could be made from the answer to this question: Are you getting more bang for your buck with a 4 lb tub of 12-4-8, or a 1 lb tub of 48-16-32? Of course, the answer is: they are the same. I know that's not your question here, though. They determine recommended solution strength based on tests that show what concentrations they feel will provide the optimum amounts of total dissolved solids (TDS) and a preferred range of electrical conductivity (EC). Their recommendations will provide a fairly strong solution that should hopefully persist in containers for approximately the recommended interval between recommended applications. With this method, it is kind of a feast/famine affair, though it has suited me well for a good number of years. Better, as noted upthread, is to supply fertilizer solutions more often and at a low rate of both TDS and EC (weaker solutions). This facilitates water and nutrient uptake.

I really can't tell you why manufacturers of off-the-shelf fertilizers don't start with a blend that has the same concentrations of N in it. Marketing, shipping weights, manufacturing considerations all play into their decisions.

I know that if you follow their mixing recommendations, you're going to come up with a solution strength, and this is regardless of the formulation, that will be within a relatively narrow range of TDS and EC. In other words, no matter if you use 5-5-5, 5-15-5, or 12-4-8, the end solution will be in a very tight range of EC and TDS. It has to be, because it has to be strong enough for the plants that want a high strength solution, and weak enough for those that want a weaker solution. Remember - this is a shotgun approach we're using whenever we buy any premixed blend over the counter, but practically speaking, it's our only choice.

You asked about the chart. The chart shows preferred RATIOS - not concentrations. That's why there is no guidelines. In a perfect world, you would know what is the preferred TDS/EC range of the plant you are supplementing, and would do a calculation to determine the weight of fertilizer nutrients needed, in the right proportions, for the volume you need to mix, to provide a solution in the ideal TDS/EC for that plant. The fertilizer manufacturer relieves you of that chore by providing general instructions on the label.

Should we feed the container or feed the plant?

I don't see how you can do one w/o the other. ;o) Kidding - I get your question. We feed the plant. Our goal is to maintain an adequate supply of the right blend of nutrients in the soil so they will always be available in at least the sufficiency range for plant uptake. Here again, the system would be pretty self-regulating if we are fertilizing with a dilute solution at every watering, and watering properly. As the plant uses water, it absorbs nutrients. Linking nutrient supply to the water supply is a very good practice, but it can present a little more inconvenience and consume some time. That's something we need to consider individually. I know I can't afford to hand water 250 plantings every day, so I use the hose to water & hand-fertilize from a can, when I can - usually every week or 2, and with a lower concentration solution.

The answer to your question about big tree:little tree is in my reply, but I'll just say that a big tree in the same volume of soil would be fertilized at the same solution strength as the little tree (remember what happens if we get too weak [starves] or too strong [plasmolysis/fertilizer burn]), but would need fertilizing more often. Again, if your fertilizer program was an @ every watering thing, you would automatically provide more nutrients by virtue of the fact that the big tree is using more water. ;o)

Did I help or confuse you?

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by bjs496 9/Houston 7/NJ (My Page) on
    Tue, Oct 30, 07 at 18:09

Hi Al,

It is always good to see you. I always come away from your post with food for thought... even if sometimes I stray.

Answer two, makes sense. It is what I've been doing. I was using a weaker solution (by half) of my liquid mix and doubling the frequency. It is a 6-12-6 with minors. In order to save time, I purchased a Dramm Syphonject and a watering wand which will handle the flow required by the Syphonject while giving a gentle output. It has worked well for me and I highly recommend it. About three months ago, I found an article on root growth and realized the significance of the concentration of salt and sugar on the outside of the root vs inside the root. Since I've been in Houston more, I have started diluting further and increased frequency to every watering.

To your answer to the first part. I understand the manufactures don't necessarily supply the same ratio of NPK nor do they supply the same concentration of NPK. If one does the math, however, not all working solutions (based on the recommended dilution) yield the same, or even similar, values for N and/or P and/or K. Maybe the difference is not really so great as it seems. Perhaps being a diabetic has made me more sensitive to this issue. Very small amounts of insulin make a huge difference. Or maybe the manufactures are approaching it from a TDS point of view.

I remember last year, in the fig forum, someone had put up an address to a Calculator (located within another Gardenweb thread but I can't post the link because apparently the owners of the website violated one or more of Gardenweb's policies and have been banned) which measured TDS in PPM of a working solution given a certain NPK concentration and the dilution rate. It only measures NPK and not the secondaries and minors.

~james


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Oct 30, 07 at 18:33

You are right in your statement, but how are you arriving there via your calculations? You said: "If one does the math, however, not all working solutions (based on the recommended dilution) yield the same, or even similar, values for N and/or P and/or K." I want to be sure I know how/what you are thinking. Expand just a little?

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Oct 30, 07 at 20:55

J - I'm going to send you a working link to the/a calculator. I suppose I'd better not post it if there was a problem before. I'll look for another & post to the forum if there is no advertising associated with it. It's pretty interesting.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by bjs496 9/Houston 7/NJ (My Page) on
    Tue, Oct 30, 07 at 23:59

Al,

I got a notice about that website being responsible for spamming and/or solicitation of their business. It is unfortunate since it seems like such a useful tool.

As you mentioned above the numbers represents the percentage of that specific nutrient in the stock (concentrated) solution. Therefore, a 13-13-13 (to make the math easy) fertilizer is comprised of 13%(.13) each N, P and K. The other 61% is filler. If you were to dilute the stock solution 1 oz per gallon of water to make a working solution, the concentration of N, P, and K fall to 0.1%(0.001).

I guess what my gripe/confusion stemmed from seeing manufactures recommending dilution rates which lead to different levels of NPK in the working solution, despite the products starting off with similar NPK concentrations.

~james


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Oct 31, 07 at 0:58

1x.13
-------
128 = .001
is surely correct, but you realize that would hold for all 13-13-13 blends. The difference in the dilution rate suggestions by manufacturers stems from the effect the 'other' ingredients has on elevating TDS/EC levels, and it's entirely possible that the elevation could come from inclusion of secondary macronutrients and/or the minors. If we wish to keep the TDS/EC in a favorable range, and if we add ions from nutrient (or even non-nutrient) source 'E', we have to reduce the amount of one or more of 'A,B,C, or D' in the solution.

I don't use a bunch of different fertilizers, James, but it seems to me that there is pretty good dosage consistency from manufacturer to manufacturer when comparing liquid and granular blends to their competitive counterparts. That's just my general feeling & I'm not certain by any means - you probably pay closer attention to it than I. ;o)

I understand, and it's good to know, how all this works, but this is way beyond anything I ever think much about in formulating an actual fertilizer plan. I look at the blend I need, check the dosage, and make an educated guess about how vigorously the plants are/will be growing, the temperature, and how long it will be until my next opportunity to take a half day to fertilize everything. Then I usually give them what I guess is a half, quarter, or sometimes 1/8 dose and forget about it for a week, sometimes longer.

I sometimes envy those that only have a dozen or so containers they can afford to fuss over (I know you have a ton, too - so I'm not including you in my envy.). ;o)

Take care.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

James, hope I'm addressing your question here. One way to look at the problem is to decide how much nitrogen to apply in terms of parts per million (ppm) and convert your fertilizer formula into the proper dilution. For example, I fertilize my orchids at 100-125 ppm of nitrogen (fairly weak) per week during the summer. The equation is (borrowed from link below):

Desired ppm / (Percent fertilizer nutrient 0.75) = oz of fertilizer per 100 gal

specifically, if you want 150 ppm N using a 20-10-20 fertilizer:

150 ppm / (20% 0.75) = 10.0 oz 20-10-20 per 100 gal (final solution)

Okay, but what does fertilizer weigh? Well, density varies, and you can weigh a couple of teaspoons to check, but data I've seen is in the range of 4 to 5 grams per teaspoon of solid.

good luck.

Here is a link that might be useful: fertilizer calcs


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RE: Fertilizer Program - Containerized Plants (Long Post)

oops, sorry, I should finish the calculation:

to get 150 ppm N in 100 gal, you need 10 oz of 20-10-20. To make one gallon of fertilizer, you need 0.1 oz, or about 3 grams (1 oz = 28 g). This is about 0.5 to 3/4 of a teaspoon of fertilizer. So you can see that the standard recommendation of about 1 tsp per gallon when making up fertilizer solutions will get you about 200 ppm N when using 20-10-20.

Why calculate based on ppm of N? Well, you don't have to, but it's a useful standard for the same reason Al's previous post normalized different fertilizers at a relative N value of 100. I also believe that specific fertilizer recommendations for specific plants, when you can find them, will often state the amount of N to be applied.


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RE: Fertilizer Program - Containerized Plants (Long Post)

Al-
Thanks for the above...this past summer I put reservoirs below, and wicks in, five gallon containers to make them self-watering for the tomatoes, peppers and eggplant I grow in them. My rationale was to save water and fertilizer( I used Tomato-tone initially and Miracle-Gro soluble later in the season).

I saved water and fertilizer and had a good season. Having seen your cautions previously about the danger of a build-up of salts in self-watering containers, I continued to water as needed from above, rather than directly into the reservoirs, as frequently as three to five times a week during the hottest part of the summer.

I saw no negative effects from a build-up of salts and would appreciate more comments from you about how and why salts build up and act the way they do. I was hoping that continuing to water from above would flush the salts as recommended by you to eliminate problems, as apparently happened, but after thinking about this again after the comments above, I am curious why these salts did not remain in my reservoirs, get wicked up again and cause problems, especially when the roots of my plants grew rather quickly through drain holes and into the water in the resevoirs. One possibility I suppose is that enough salts remained settled in the bottom of the reservoir and were not wicked back up enough, or I "overwatered" enough at times to flush enough of the salts out of the reservoirs...purely by luck!

Your thoughts?


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Nov 6, 07 at 18:01

I saw no negative effects from a build-up of salts and would appreciate more comments from you about how and why salts build up and act the way they do. I was hoping that continuing to water from above would flush the salts as recommended by you to eliminate problems, as apparently happened, but after thinking about this again after the comments above, I am curious why these salts did not remain in my reservoirs .....

Salts build up because they consist of dissolved solids. When water evaporates, the solids cannot change to a gas and are left behind. This is accumulative and any closed system will eventually accumulate toxic levels of salts unless you water with deionized water and the initial salt content is insufficient to reverse or severely impede normal osmotic function.

They act as they do because of their effect on osmotic function (see upthread). Low concentrations of nutrient ions, even in the right proportions, cause deficiencies. High concentrations of ions make it increasingly difficult and eventually impossible, as the concentrations rise, for plants to take up water and the nutrients dissolved in it.

The salts did get wicked up in the normal wicking action of your set-up. You, however, flushed them to the reservoir via top-watering. They did not stay in the reservoir because you applied sufficient water to dilute and overflow the reservoir, carrying the salts out along with the surplus effluent.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Al,
Thanks.
Tom


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Feb 20, 08 at 9:56

Hi, Jimmy. I left this on another forum, but it may be of interest to you. If you still have questions after reading it - please ask:

(House)plants go about the business of living and adjusting their metabolic needs according to certain internal rhythms and cultural conditions. Their internal clocks and lowered light levels are key factors in the marked slowdown most of us observe in our plants in winter; however, slowed growth cannot simply be offered up as proof of "dormancy". Just because we can't see plants growing or we think they are not growing is insufficient cause for certainty. In fact, in winter, our plants are carrying on photosynthesis and respiration - keeping their systems orderly, and going about their metabolic processes in a "business as usual" manner. They are just doing it at a much-reduced rate.

Why then, would we deprive plants of the building blocks they need (fertilizer) to produce the energy (make food) to carry on their metabolic processes? In nature, do the nutrients just disappear from soils whenever a plant's internal clock or cultural conditions cause slowed growth? Of course not - and the idea is absurd. Even if you cannot SEE plants growing, they are STILL producing and storing photosynthate to be used in a later push of growth. Withholding fertilizer, LIMITS the plants ability to carry on this important part of its growth cycle. Plants are efficient users of nutrients, but they cannot make something from nothing.

If you were striving for ultimate growth and best vitality, it would be REQUIRED that plants should ALWAYS have a full compliment of ALL the nutrients essential for growth in a solution strong enough to supply all nutrients in the adequacy range, but not so strong that it makes it osmotically difficult for the plant to absorb water and nutrients. This bold part is key.

The reason it is so often parroted that we should refrain from fertilizing in winter isn't because the practice itself is bad for plants (simple science and a little knowledge of plant physiology is all that's needed to dispel that myth); it's because so many of us are growing in a soil that simply will not allow us to fertilize in a way that is best for the plants.

Remember, I'm often at odds with growers who support a practice out of convenience or a necessity based on cultural limits they have either placed on themselves or that they must work within. Soo often you'll find me saying that grower convenience and plant vitality are often at odds with each other and are often mutually exclusive.

Where am I headed? Well, if we KNOW that availability of low levels of all nutrients at all times is best, even in winter, why are we so often admonished against winter fertilizing? It's because of the soils we use. Even without the addition of fertilizer to our irrigation water, the level of salts and total dissolved solids (TDS) in our soils (for most of us) continues to accumulate over winter because of watering habits necessitated by slow soils. Some limit themselves by soil choice and then try to tell others that ARE using a soil that allows them to fertilize appropriately that they are doing something wrong. This, because the some lack adequate understanding about what is really happening with regard to plant's actual nutritional needs.

So YES, many readers are limited to being unable to fertilize adequately because of soil choice, and just because plants carry through winter w/o additional fertilizer supplements over the dark months, is not an indication of anything except that plants will usually tolerate it. Is it the end of the world if you don't fertilize in winter - or you can't? Not really, but you can see that there really is a better way than simply withholding nutrients from an already stressed plant.

Dr. Alex Shigo: " ... correct the stress, which will lead to strain, that if uncorrected will lead to the death of the organism."

I use fast soils that drain freely & I fertilize with my own concoction (which is basically MG 12-4-8 with micronutrients + STEM + some Sprint 138 Fe chelate [an iron supplement for high pH water applications] + MGSO4 + vinegar) at EVERY watering, and it works extremely well. When I add the TDS of my water and what I add to it, I'm applying the right mix of nutrients at every watering at a rate of less than 300 PPM of TDS which puts me on very sound horticultural ground. In summer, the same plants will be fertilized at somewhere near the rate of 1,500 - 2,000 PPM weekly - a big difference.

If you are using a soil that allows you to water freely at every watering, you cannot go wrong by watering weakly weekly, and you can water at 1/8 the recommended dose at every watering if you wish (with chemical fertilizers, i.e. - there are some other considerations with regard to delivery of nutrients when using organic sources that depend on biotic activity to make nutrients available in elemental form, but I think they are outside the scope of the points I wanted to make in this reply).

Take good care.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Well Al, I agree with your stance on what happens in nature. I usually try to look at that with most things even outside of plants. I just heard so many times about people burning plants by fertilizing in winter and so many people recommending the dormant stage. Now that I think about it, not sensible. I know my plants are still growing even if at a slower state because I have a rubber tree plant that has been growing new tiny leaves and even a new stem this winter.
So I guess I only have a couple of questions left. I understand the 12-4-8 and the stem and iron. What is the mgso4 and why the vinegar? The 300 ppm for winter and 1500 ppm in the summer, what would those be around in laymans terms? A couple of eyedroppers per pint? Is there a place online or at local nurseries where you can get all these together? Also are you recommending this feeding each time watering or weekly?


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Feb 20, 08 at 10:31

Jimmy - I should have asked you what you meant by 'purified water'. The marginal necrosis or tip burn could be the result of plasmolysis (fertilizer burn) exacerbated by the dry conditions we zone 5rs have to tolerate during or winters. (-8* predicted for tonight's low, btw) That seems less than probable though, if you're watering so that at least 10-15% of the irrigation water is passing through the soil at each watering.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Feb 20, 08 at 11:18

Sorry - I was posting to your previous message as you were writing your most recent.

I just heard so many times about people burning plants by fertilizing in winter and so many people recommending the dormant stage.

Ok - now you understand at least what is desirable as far as a winter fertilizer program goes & that houseplants are never really dormant. ;o)

What is the mgso4 and why the vinegar?

The MgSO4 is Epsom salts and works into my fertilizer program because I use gypsum as a Ca source in houseplant & gritty soils instead or dolomitic (garden) lime. The gypsum lacks Mg and the Epsom salts is what supplies it. The Fe chelate is used because my water varies in pH from about 8 to 8.5, and Fe uptake has occasionally been a problem. The chelate bonds the Fe to organic molecules and is specifically formulated to facilitate uptake in high pH situations. The vinegar helps neutralize alkalinity.

The rate of 300 ppm is about 1/8-1/4 tsp of 12-4-8 per gallon of water. Half the solutes in the 300 parts comes from the tap water & the rest is from the fertilizer & micronutrients. The higher concentrations would represent a 3/4 to full recommended dose concentration, which I apply every week to 2 weeks (I can easily do this because of the fast soils & daily irrigation).

All the 100+ plants I tend indoors over winter take about 3-4 gallons of water to irrigate. I mix it ahead in gallon jugs so it comes to room temperature after adding about an eyedropper full (I estimate 20-24 drops of the 12-4-8 with the micros, Epsom salts, and Fe chelate already mixed into the fertilizer concentration per gallon of water) of fertilizer plus a tbsp of vinegar in each. The plants get fertilized at every watering. When I move the plants outdoors in May, I begin the weekly - bi-weekly regimen because plants that are growing with good vitality in good light & other cultural conditions will tolerate much higher fertilizer concentrations in the soil.

I'm not sure where you can buy the Fe chelate (very expensive @ around $90/5 lbs), and it may not be necessary. There may also be alternate chelates that would suit your needs if you feel they are necessary. The STEM is also sometimes difficult to obtain in small amounts. I buy 50 lb bags @ around $75. I think you can buy either STEM or Micromax in small quantities at

Southwest Fertilizer
5828 Bissonnet
Houston, Texas 77081
(713) 666 1744

if you can't, and want these products, contact me off forum and I'll help direct you elsewhere.

Take good care.

Al



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RE: Fertilizer Program - Containerized Plants (Long Post)

Al, Have you seen this product before, if so what do you think about it? http://www.advancedsoils.com/


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Feb 20, 08 at 13:30

The product is most likely clinoptilolite or a man-made equivalent. It would primarily be useful as slow release provider of potassium. If the product had been previously treated with ammonium, it could also be useful as a slow release provider of nitrogen, or other micronutrients as well, if appropriately treated. Clinoptilolite is also nearly as porous as Turface, so will hold lots of water while improving aeration. It also has a high CEC, though CEC isn't particularly important in container culture

IMHO, it's not the miracle product the sellers are proclaiming it to be. If I was going to use it in my soils I would use it to replace all or a part of either the Turface or perlite components. How I would decide if it was appropriate (for me), since I don't think it's use represents much probability of improvement over my current nutrient supplementation regimen, is by considering the cost factor and physical properties, such as the size of the particles. Best, would be particulates in the 1/16 - 3/16 size range with the 1/16-1/8 size range favored.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

ps3 -

I suppose it's a point of view whether 12-2.5-14 is close or not to 12-4-8, and from there to Al's plant tissue ratios of 10-1.5-7 Main idea I took away from the above and from the Argo papers was the general overuse of phosphorus.

FWIW, I discovered during my own amateur fertilizer mixing efforts that getting an exact, arbitrary ratio of nutrients, particularly NPK with Ca/Mg, is difficult if not impossible because the raw fertilizer salts (potassium nitrate, ammonium phosphate, calcium nitrate) dictate part of the ratio, and solubility limits dictate much of the remainder. This is particularly true if (like me) you are looking to exclude sodium from the fertilizer.

Again, FWIW, here is the formula I used in "home-brewing" a concentrated, liquid fertilizer stock, with apologies for non-readability. Copy and paste in a monospaced font, like Courier, to see the table format:

Salt Formula MW element element MW % element in salt % N in salt target % grams N % final element % target
calcium nitrate tetrahydrate Ca(NO3)2-4H2O 236.2 Ca 40.08 17.0 11.9 8 471.46 5.2 7.5 Ca
magnesium nitrate hexahydrate Mg(NO3)2-6H2O 256.4 Mg 24.31 9.5 10.9 2 210.94 2.2 1.9 Mg
potassium nitrate KNO3 101.1 K 39.10 38.7 13.9 12.3 318.04 4.1 11.5 K 14.0 as K2O
monoammonium phosphate NH4H2PO4 115.0 P 30.97 26.9 12.2 1.31 48.64 0.6 1.2 P 2.8 as P2O5
iron-sodium EDTA Fe(III)-Na-EDTA 367.1 Fe 55.85 15.2 0.0 0.177 11.63 0.0 0.166 Fe
manganese sulfate hydrate MnSO4-H2O 169.0 Mn 54.94 32.5 0.0 0.088 2.71 0.0 0.082 Mn
zinc sulfate heptahydrate ZnSO4-7H2O 287.5 Zn 65.37 22.7 0.0 0.041 1.80 0.0 0.038 Zn
cupric sulfate pentahydrate CuSO4-5H2O 249.7 Cu 63.55 25.5 0.0 0.044 1.73 0.0 0.041 Cu
boric acid H3BO3 61.8 B 10.81 17.5 0.0 0.018 1.03 0.0 0.017 B
ammonium molybdate tetrahydrate (NH4)6Mo7O24-4H2O 1235.0 Mo 95.94 54.4 6.8 0.018 0.33 0.002 0.017 Mo
Totals 1068.31 12.1 12.1 N

dissolve
in: 455 mL distilled water

and adjust to pH 1.5 with nitric acid.
1 Tbs per gal dilution yields ~ 100 ppm N

Also, the link to Bill Argo's original articles on orchid nutrition is below. Getting a spam notification from GW, so remove the spaces.
[w w w . f i r s t r a y s . c o m / n u t r i t i o n . h t m]


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Thu, Feb 21, 08 at 17:04

Thanks, Tee. I see we're in agreement re. the over-abundance of P in many of the popular blends like 20-20-20, and especially the bloom-booster formulas like 15-30-15 and even 10-52-10.

I think you can tell that I wasn't trying to nail anything down tight, as far as being too rigid about a fertilizer program - just trying to offer an overview & food for thought, along with leaving seeds for the idea that though a 3:1:2 ratio fertilizer may not be the best in every case, and it's still a shotgun approach, it really is closer to supplying the nutrients in the ratio most plants need/use than most of the other blends you commonly find in the majority of retail outlets.

Thanks for the efforts - the input and insight is appreciated.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Dear Al, I can't tell you how much we all appreciate your thoughtfulness, and your taking the time to share your expertise with us. I have been wanting to tell you that what I learned from you about free draining soils and good areation saved my roses and other container plants during the extremely wet weather we had last year. I have been used to determining the exact water content of my plants since it has been so dry here in Texas for the last 6 years since I started container gardening. Without the knowledge I gained from you the plants would not have made it with flying colors.
Since fertilizer is always an issue with containers, I have already used the knowledge I have gained from you in shopping for my spring fertilizer. I find it is amazingly hard to find the ratio that is best. They are all over the cotton patch! However I think I have done it and I am very grateful for your help. I never miss a post although I rarely comment--the other seem to know so much. All of the comments are so useful and educational too. THANKS TO YOU ALL FOR HELPING US PLANT LOVERS.
Betsy


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Thu, Feb 21, 08 at 23:08

Oh, Betsy. Thanks for making yourself known. You probably have no idea how welcome your kind words are. It's been pretty rough sledding on the container forum lately, and knowing that something I might have shared has helped you means so much to me right now. ;o) Thank you for your kindness and the effort it took to share your thoughts.

Please don't hesitate to ask, if you ever think there is anything I can help you with. I hope we see more of you here, too! ;o)

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Thanks, Al. It's funny, above I was responding to a recent
post asking about the (slightly) different feritlizer ratios quoted throughout this thread. Now, that post has been removed, and my response is still here, dangling.

On another note, this is a good forum for ideas and healthy discussion, and it has been tremendously useful for me (and the plants!) We have all benefited from the generousity of knowledge and spirit that the more experienced growers have shared with us, and from the moderate tone and polite responses. Here's a vote for keeping it this way. High functioning forums (eg Orchids, Ornamental Grasses, Containers) all have these characteristics. One only needs to wander over to Citrus or Growing under Lights to see what happens when the delicate forum ecosystem is disturbed.

cheers all!


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Fri, Feb 22, 08 at 10:57

No matter if your post is dangling; your intent is clear - and thanks for the explanation. I know what's going on, but it might have confused those who haven't been following the thread. ;o) There's no sense in going into details, but you're exactly right about forum function. It is so much more fun around here (GW) when the mood is light hearted and information is exchanged as a result of our desire to help one another. I love lively conversation & even friendly debate, but for me, the fun changes when I'm unable to imagine a smile on a poster's face, or when a post erases my own smile. GW is a hobby for me & I prefer it to watching TV - even often neglecting my reading to be here with the folks I enjoy so much. (Don't worry - I have PLENTY of interests outside of GW to keep me busy) ;o)

Take care, Tee - and thanks again.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Dear Al, and everyone else who supplied information to this thread,

Whew! It's a lot to digest! I normally hang out on the Hippeastrum forum, and there's usually talk of what ratio of NPK is best for our bulbs of choice... there are really no commercially available fertilizers that are well-formulated, it seems, although some are better than others... I have found in the course of experimenting that a weak solution of general houseplant fertilizer used approximately every other time I water seems to suit my bulbs fine... although, I can't wait for spring to get here so I can move them all out to the garden and top dress them with my compost... I know that will make all my plants so much happier and healthier.

How do you feel about time-release fertilizers such as Osmocote? And is there a readily available brand of fertilizer for most container grown plants that you would recommend over others?

Anyway... just wanted to say thank you for explaining how plants uptake nutrition in a clear manner that even I can understand! Keep the information coming; I'm out here listening!

Waiting For Spring In Central IL


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Sat, Feb 23, 08 at 19:57

Hi, Jodi - welcome to the container gardening forum (If you haven't already been here before), ;o) and thank you for the kind words! We have a local radio personality here who goes by the name JodiK. ;o)

I think that CRFs have a place in container culture. I think they are better, incorporated in soils when you make them, rather than broadcast on top of soils, and I don't like to use them late in the growth cycle, so there is reduced chance of unwanted release while indoor plants are quiescent or outdoor plants dormant. I understand, that temperature has substantial influence on release rates, but even during periods of cool weather, there can be damaging release of nutrients that comes from temperature flux and extended intervals between irrigation. IOW, I try to apply early and like to be reasonably sure the nutrients have largely been spent by the time plants are dormant or want to rest.

I really cannot tell any difference between brands of chemical fertilizers I have tried. I use MG 12-4-8 almost exclusively, but I wouldn't think twice about using something from Peter's or Schultz - or any other brand I might happen to find on the shelf. The formulation is much more important than the brand.

Here's what I think about growing amaryllis. I would grow in a spare soil like the gritty mix recipe that's floating around this forum somewhere, and fertilize them with a higher N blend with low P like the 12-4-8 with micronutrients that I usually use, for the first 3-4 months after they bloom. After 3-4 months, I would switch to something with a 2-1-2 ratio like 6-3-6 or 15-5-15 until florescence is ended. Don't forget to make sure the plants are getting Ca & Mg. They are not included in MANY, if not most, soluble fertilizer mixes.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Thank you... for both the welcome and the information... I usually only use time release feeds in my large patio pots filled with annuals... planted and fed in spring, then minimal care is required for the rest of the growing season.

This is my first year collecting hippeastrum bulbs, and I will summer them all outdoors to recharge... one thing I do know is that they absolutely need good drainage, so I've been working on mixing a medium that I think "feels" right and drains well and quickly. They do hate wet feet, and it tends to promote rot if they are too wet for too long.

I'm not at all good with numbers and science, and some of the more technical fertilizer talk is lost on me. But I do try to feed my bulbs, especially after flowering when they become heavy feeders, with a rather balanced plant food liquid, MiracleGro.

With our hard water, I also flush them regularly, and use unsoftened water to avoid too many salts. Clay is my pot of choice, with a layer of charcoal at the bottom.

I normally have gorgeous patio pots every year, and I know it's due to a combination of medium, feeding and proper watering.

Thank you for getting back to me so fast... and thanks again for your good explanation of how plants work! I learned quite a bit from reading this thread!


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Sun, Feb 24, 08 at 12:27

Sounds like you have everything under control then. I hope you hang around awhile, or at least come back to visit us when the mood strikes, Jodi. :o) Take good care & good luck.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

I don't know if I'd say I have everything under control, what with life being so hectic, as it is! But, in the gardening department, I try... :-)

I'll be around... whether here or the Hippeastrum forum... container gardening and raised beds are every year projects for me... I keep several large patio pots filled with assortments of plants, and have a current total of 4 large raised veggie beds... not to mention the bulb bed, rose garden and other areas containing perennials and shrubs... I'm lucky enough to live out in the boonies where garden space is vast, and large animal manure is plentiful!

Thanks again for all the great info... I'll be sure to post photos of my gardens and containers come spring... right now, we're under snow. Below is a link to my photo album, which contains mostly bulb photos, but there are also pictures of my garden plants of last season... Enjoy!

Here is a link that might be useful: My Photo Album


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RE: Fertilizer Program - Containerized Plants (Long Post)

Al,

The best fertilizer I could find at home depot was a miracle grow with the right ratios of N, P, K, Mg, Fe, and Zinc. However, no calcium, sulfur, boron, copper or chlorine. How important are these others and what can I expect without them? Thanks, Jim


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Thu, Feb 28, 08 at 23:30

What were the %s of NPK? Are you sure it wasn't Mn it contained instead of Mg. If it contained any Mg, was it .5%?

It's extremely important for all the nutrients, including micro-nutrients to be present in adequate amounts or growth will be limited. There are 6 factors that affect plant growth and yield; they are: air, water, light, temperature, soil or media, nutrients. Liebig's Law of Limiting Factors states the most deficient factor limits plant growth and increasing the supply of non-limiting factors will not increase plant growth. Only by increasing the most deficient factor will the plant growth increase. There is also an optimum combination of the factors and increasing them beyond the optimum, individually or in various combinations, can lead to toxicities for the plant.

That said, S, Bo, Cu, and Cl are rarely deficient in container soils, though they CAN be. You do need to be absolutely sure that your plants are getting ample Ca and Mg, though, and it's a GOOD thing to be sure your fertilizer has all the needed elements or to supply a micro-nutrient supplement when you fertilize, for optimum growth.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Al, Sorry. I may have typed in the wrong abb. It has 12% Nitrogen, 4% Phosphate, 8% Potash, .1% Iron, .05% Manganese, and .05% Zinc. The last three are chelated.

So if I am understanding you correctly, the sulphur, boron, copper, and chlorine will happen naturally and do not necessary need to be added but the calcium and magnesium are going to be needed. I do use purified water which takes out chlorine, will that have an effect on needed chlorine also or no. Thanks. I am having a hard time finding one with the calcium and magnesium unless I dissolve my own from mineral supplements.


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Fri, Feb 29, 08 at 19:53

Yes - your understanding is correct.

If you're using a commercially prepared soil, it will almost certainly have been pH adjusted with dolomitic lime, which supplies the Ca and Mg. If you're making your own soil, simply add 1/3 - 1/2 cup per cu ft of damp soil when you make it.

There will still be ample Cl in your soil, even if you use water with no Cl content. It's needed in minuscule amounts.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Sun, Mar 23, 08 at 10:24

Yesterday, I was doing some research, trying to help out a person who had contacted me by e-mail. As I was searching the net, I found a fertilizer that was unknown to me, but now after discovering it, I'm very excited about it. I'm not sure how long it's been on the market, but it has a 3:1:2 ratio and a full compliment of all the minors. It also has only 1/3 of its N in ammoniacal form, so cool weather and/or periods of low microorganism activity shouldn't cause problems with (often undiagnosed) ammoniacal toxicity like the fertilizers deriving their N from urea.

I'm not going to link to it directly, but you can find out more about it by using the search words Foliage-Pro 9-3-6.

Take care.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Al: I saw mention of the 9-3-6 by you on another post and I wanted to look it up. I too am interested in a more complete blend for the average gardener and this one looks to work on several levels. I do like the higher nitrate form for cool season growing. Here in Texas the winter annuals pansies, flowering kale, snapdragons all would appreciate a formula such as this and I will be looking to try some this spring while it is still cool enough to test a little. I also like the lower sulfer that sometimes gets excessive in some ammonia sulphate formulations.

I still am looking to get better info on the osmocote plus with minors and will be calling scotts today to see what I can get for a solid answer about its usability in container culture. I am already committed to some containers but need more info before I can feel good about talking more than personal opinions on its use that way here.
As always Al thanks for sharing and continuing to help any and all of us be able to understand the confusing world of fertilizers as well as your incredible patience in assisting anyone you can pro or hobbyist grower with so much more. You a true diamond shining like a beacon on the hill guiding us gently to a more fruitful growing experience.

P.S. I just got off the phone with scotts and the rep couldn't help me so I asked for a supervisor and got the basic reply I expected and that was that the labeling is for in-ground applications because they have not completely tested to a level that they can guarantee its safety for a consumer to use this product. She tells me that there this is a different formulation with different inert ingedients than the osmocote plus/pro formulation. I feel that it will personally work well but because of legal requirements of labeling laws that scotts will for at least the time being will only offer the in-ground reccomendation for the orange label 4.5 lb osmocote/plus (with secondary and micronutients). It may come to pass that this will become available with proper dosages and legal label requirements in the future. I will continue to do my own comparisons and see how it does and report back as I can. In the mean time anyone interested in using it for container applications consider that scotts is legally required to not state it use in this manner and there for if you choose to use it in this manner it is at your own risk. I for one am taking this risk on a modest level and if I have success or problems I will report back to the container forum what I am seeing and observing over this growing season. I suggest people look into the Foliage-Pro 9-3-6 as I will be doing the same. I will be testing it against the osmocote plus and with the osmocote plus. I will also do some tests with straight 18-6-12 osmocote with Foliage- Pro 9-3-6 additional feedings. Maybe over the course of a season I can see to my satisfaction whether any of these combinations will provide any clearer answer to what I will use more of next season. As always Happy Growing and Planting to All David


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Mar 24, 08 at 17:29

Oh my, Dave - I don't know what to say, except thank you for your comments, which I think are kinder than I deserve. I really appreciate your thoughts and am always glad to hear/know my efforts are appreciated.

Yes - I mentioned the new (to me) find in several places because I got pretty excited about it, and I have to say that the excitement was much more for others than it was for myself. I think it can/could/should/will be as near a fool-proof soluble fertilizer, for any hobby grower who is at all confused or undecided about what fertilizer to use, as they could hope to find.

Thanks for concurring too, that the 9-3-6 merits a look. It feels better when you're not a lone voice, crying in the wilderness. ;o) I ordered a gallon of that & another gallon of Pro-TeKt, so I'll have a good jump on spring, if it EVER arrives. ;o)

I have been following your Osmocote-Plus has CRF Minors thread you referred to above, & sort of watching to see what you found out from the Scott's folks about the 15-9-12 +. I see your hopes were at least temporarily put on hold by what seems like will probably turn out to be a technicality. I was wondering why their Pro + minors fertilizer in 19-5-8, 8-9 month blend, or the 19-5-9, 12-14 month product wouldn't do well by you/us? Was it because you were trying to help out those of us who were looking for a container-compatible blend with minors that you could buy in more reasonable volume than 50 lbs at a time?

Thanks from me, and I'm sure I speak for others, for keeping us posted, too. I know you as a very valuable asset to these forums & also appreciate your contributions. I know I/we can always rely on what you offer to be technically sound and informative.

Take care, Dave.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Al:
Thank you for your kinds words too! Yes I am constantly looking for materials that will help fellow gardeners be able to have a easier and less stressful time growing whatever and however they can. I am looking for the common every day gardeners option to all the materials a professional gets to have at his disposal. I wish that the inequaties of it all were not so but I find so much of the horticultural field rife with half-truths and supposed silver-bullets and this that and the other. As a garden center manager I fight to find a balance of truth within all these half truths from the advertising that speaks of just use (fill in the blank:( and you to will have a perfect (fill in the blank:( I have such a challenge already try to help folks with the dizzying array of garden ferts, herbicides, insecticides, growing mediums and such that I almost go batty trying to keep it simple and easy for the average joe to have good results with their garden experience without toxifying the plantet or themselves when I know there are some simple common sense approaches that can be easily understood and yet do a good job for joe average gardener. I thrive on understanding the technical stuff but that is for me and not for joe average gardener and I can't go home with them and give them a crash course of hort 101, 102 and 103 as much as sometimes I might want to.

I love this forum for the folks here that are trying to offer and seek basic and technical answers to why for all the media hype that some things are just common sense and the rest is a just a bunch of malarkey that belongs on a 5th avenue story board for how to get someone to part with their precious hard earned dollars that will at best leave them poorer and in no real sense a better flower, tomato, tree or whatever else they are trying to grow for the first or umpteenth time.

I love nature and the simple joys of watching a seed sprout or a flower open or the incredible burst of flavor I get from that home grown tomato. The joy of a butterfly flitting about on it journey gathering its sugary food and pollenating the flowers as it goes about it business day to day. The bees buzzing the hummingbirds humming. It is all so intoxicating to me like a fine wine to be savored, shared and cherished for its simple beauty. I still get giddy as winter turns to spring and life picks up it pace and has all the senses a fire with all that is possible with the renewal of another season of growth upon us.

Boy it is time to shut up! I could go on and on why I do what I do but it all comes down to wanting to help as I can my fellow man or woman to look, learn, and listen nature offers so many of lifes answers with a simple KISS (:keep it simple stupid:) and on that note I offer you all a fond adieu. It time for some planting oh my what will I do, what will I do some much to plant, so little time to do it, spring has sprung and it is time to have fun.
Happy Planting and Growing to all and have fun today. Enjoy nature this very day, in some simple way. You will be glad you did and life will seem a joy again no matter what this day has seen for you. David


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RE: Fertilizer Program - Containerized Plants (Long Post)

In my search for various kinds of fertilizers, I have found another product that may be decent.
I first found a product called Multicote. It is made by a company called Sun Gro Horticulture. Unfortunately, I was unable to find any place that sells this product online.

What I did find tho, was a product called Dynamite All Purpose. The company name is "Dynamite", and will come up in a search if you add the word fertilizer. Maybe someone has heard or used this product name before. Home Depot carries the brand.

I was looking for the "All-Purpose Select Plant Food" that has 15-5-9 plus micros. The best I found tho was the "All-Purpose Plant Food" which is 18-6-8. I figure I can just add some extra potash when I make the soil.
The Micros are Mg 1.20%, B .02%, Cu .05%, Fe .20%, Mn .06%, and Mo .02%.

Ross


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RE: Fertilizer Program - Containerized Plants (Long Post)

The only thing missing is the calcium which could be supplied with gypsum depending on the sulfer content in the dynamite. There is more than osmocote plus out there and I think that because of this scotts is trying to play catch up on a market that is passing them by. Proven Winners has complete package that also looks like it may be useful. I got a few small packages at a hort trade show last year. I still haven't had time to do proper follow up and a cost analysis for what you are getting. I am a little picky about price ratios to what your getting and I at this point I can't say a whole lot but it might be another one worthy of consideration.
Good find and thanks for sharing we all are richer when we know what some of our choices are.
Happy Planting David


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RE: Fertilizer Program - Containerized Plants (Long Post)

Al, Quick question for you. I have used Dyna-Grow products in the past and have been mostly happy with them, but I am curious as to what you mean by your 'weakly weekly' idea.

With the Foliage Pro fert the instructions call for 1/4 tsp with each watering for 'maintenance' or 1 tsp every week for 'production'. What rate/frequency do you plan on using it?

To the extent you will use it will you modify your use of CRF, lime and STEM in the planting mix?


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Mar 26, 08 at 7:45

Some of this is background noise & more for the benefit of others than you, but "Weakly weekly" is just a variation on fertilizing on a 'maintenance' schedule. In a soil that you can irrigate so water drains from the container every time you water, there is very little danger of over-fertilizing when using recommended solution concentrations because we dilute the fertilizer concentration in the soil and part of it (fert)is carried away each time we water. The recommended doses do raise the level of TDS ans EC quite high though, which can make it difficult for plants to absorb water. This would be particularly true in a case where there is already soluble salts build-up in soils due to poor drainage, and in cases where the water is particularly hard. "Weakly weekly" eliminates this 'spike' in nutrient levels and still keeps nutrients available in the 'adequate' range.

Fertilizing at full strength can also create a problem I never see mentioned on the forums. Exposure to nutrients at the high end of the luxury range, such as we would expect immediately after fertilizing at full strength, can create deficiency symptoms of several nutrients when the level of those nutrients returns to more acceptable, even ideal levels.

With the Foliage Pro fert the instructions call for 1/4 tsp with each watering for 'maintenance' or 1 tsp every week for 'production'. What rate/frequency do you plan on using it?

I have just under 100 plants I maintain indoors (all in smallish containers) and it takes 3-4 gallons of water to fertilize them when I water (every other day for all but about 20, which I water daily). While those plants are indoors, I'll mix fertilizer and vinegar into the water and let it rest for a day. Every plant will probably be fertilized at close to the 1/4 tsp rate, each time I water. It will take a month or two to settle on a rate I like.

Once those plants are moved outdoors and added to the 100 temperate plants + another 50 misc containers, I'll be watering from the hose - no way can I take the time to water from a can, outdoors. At that point, because of time constraints, I'll need to fertilize at close to the recommended high dosage on a weekly schedule. But, that's just how things fit into MY plans. I still think it's better to use a free-draining soil and fertilize at somewhere near 1/4 the recommended strength at every watering, if you have the time.

To the extent you will use it will you modify your use of CRF, lime and STEM in the planting mix?

My guess is YES, but I'm unsure yet to what degree. It may be as simple as eliminating the use of any liming materials in the gritty mix I use (needs no pH adjustment - should already be around 6-6.5), but I suspect that I'll continue to use dolomite in the 5:1:1 mix as a pH buffer.

Even though I list CRF in the mix I suggest, much of the time I don't use it. If you're diligent about your fertilizing efforts, its not needed. I only suggest it for those who either don't fertilize often enough, or forget altogether. Since I already use soluble fertilizers either alone or in conjunction with with CRFs, nothing will change there.

I do know that when I start using the 9-3-6, I'll likely eliminate the use of STEM and Micromax. Time will tell how I like THAT, because I'm extremely happy with their ability to deliver the minors. As I noted, I'm more excited about the 9-3-6 for others than myself. Over time, I've developed a way to blend the STEM into the MG 12-4-8, along with a little MgSO4 and a special Fe chelate, so all I need to do is add 1/2 a capful to 2 gallons of water & I have everything mixed in 15 seconds. Personally, the change won't represent much difference to me, I'm sure; but to those that are a little undecided about their nutrient delivery plan, I think it can represent a huge improvement over just simply supplying a balanced blend that's devoid of most of the minor elements.

Take care. What a good job you're doing on the forum!

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

(reposted this from another thread)

Al,
I am new to container gardening - This year I'm trying several large half-barrels - I think they were wine barrels but may have been whiskey. I am 'absorbing' all of your very technical posts, but I think I'm drowning (read=overwhelmed) in all the unfamiliar terms!

If you have a spare moment, can you define some of the ingredients in your famous soil recipe you listed in that very informative thread?

COPIED FROM AL:

"My Basic Soil

I'll give two recipes. I usually make big batches. I also frequently add agricultural sulfur to some soils for acid-lovers or to soils I use dolomitic lime in.

5 parts pine bark fines
1 part sphagnum peat (not reed or sedge peat please)
1-2 parts perlite
garden lime or gypsum
controlled release fertilizer
micronutrient powder (or other continued source of micronutrients)

Big batch:

3 cu ft pine bark fines (1 big bag)
5 gallons peat
5 gallons perlite
2 cups lime or gypsum (you can add more to small portion if needed)
2 cups CRF
1/2 cup micronutrient powder (or other)"

Where/What are the best pine bark fines?

What is CRF?

What micronutrient powder do you recommend?

THANKS AL!!

-Jules


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Mar 26, 08 at 17:22

Hi, Jules. Sorry - ;o) Whenever I write something, I often consider if I should use the proper hort terminology, or use terms we more commonly see. I think I kind of do a little of both, but I never try to use technical terminology to impress anyone. There are LOTS of more technical terms I could be using in place of those I regularly post. You might be able to tell that I LOVE to help people learn, and as I write, I always try to help the less experienced growers learn something new, or share something with the experienced growers they might not have thought of in awhile. If I use a word that isn't very commonly used on the forums, or seems technical, I use it in hopes that readers will be interested enough in what they are reading to look it up or do a search to see what it actually does mean. It's absolutely amazing what you will learn that is incidental to what you are researching, yet VERY valuable when you look words up. Personally, I NEVER read a word on these forums that I won't take the time to look up if I don't understand it. Please realize that I'm speaking in a kindly tone, and not in any way taking you to task for asking - I'm really glad you did. I simply offered that info so you could know where I'm coming from. ;o) Feel absolutely free to ask anything else you wish to know. If I can't answer it, there are plenty of smart people to fill in where I fall short.

Generally, the finer the fines, the better I like them. The finest material is usually partially composted, too, which I consider a plus (not because of any benefit from the 'compost' part, but because there is less N immobilization in/from the partially composted product).

CRF = Controlled Release Fertilizer

I use/incorporate Micromax (insoluble) micronutrient powder in all my soils when I make them. When the Micromax has become ineffective, I use STEM, a soluble mix of the Micronutrients. Both of these will probably prove to be difficult for you to find in quantities less than 50 lbs, so I suggest you look to products like 'Earthjuice MicroBlast' or similar. If you decide to use the 9-3-6 fertilizer we were/are discussing upthread, you probably won't need to worry about adding any of the secondary macronutrients OR the micronutrients unless you decide you wish to 'fine tune' something for a particular plant.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

I guess I am different, but mine works as well.
2 parts woody potting soil
2 parts peat potting soil
2 parts my own compost
1 part worm castings
2 parts composted cotton burr
2 parts composted cow manure

to this I add

greensand
bone meal
blood meal
cottonseed meal
pelletized dolomite lime
course ground lime stone
ground oyster shells
a little rock phosphate
used coffee grounds
Mikes Microrhyzae (sp)

I also make small "pools" of
bone meal
blood meal
cottonseed meal
worm castings
deep inside the containers.. or... make small "tunnels" from top to bottom with the above for future food needs for the plants.

I add a handful of alfalfa pellets on top of the mix.

the only other thing I add is teas several times throughout the growing season. I have several pepper plants that are in their second year and havent slowed down yet. I do mix this base several months in advance to let some of the "cooking" heheheh take place before the transplanting occurs.

What's your opinion of what I am doing? I know it's a little costly, but I get all my supplies at below contractor pricing so that helps greatly, as well as in bulk too.

I kinda specialize in peppers and tomatoes, but grow many other container plants as well. Most of the plants grow well beyond what most advise is the largest range of size seen. I do use 5 to 15 gallon containers as well, so rootmass can be tremendous.

I also have never, in the two years I have used this, lost any plant to disease or insects.

Beginning this year I will try to only use pond and rain water instead of the garden hose!!I have built a system of interconnected 33 gallon trashcans to trap all gutter run off.

Hope ya don't mind my hijack!

Good luck! TiMo


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RE: Fertilizer Program - Containerized Plants (Long Post)

Whew - thanks Al, and TiMo for the informative fertilizer and soil concoction brews!

I have much more to consider and study now as I am creating my barrel gardens. I will be trying many of the things you suggested and I very much appreciate your patience with defining and explaining the process of creating a well-balanced container garden!

I'll let you know how things go as I plant =)


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Thu, Mar 27, 08 at 17:11

RD - I'm glad that you can make your organic program work for you, and if it works well for you, there's no need to change anything because of what I think. I probably wouldn't have made much comment on your post, other than to thank you for participating & offering your thoughts, but since you asked, I'm afraid I have to answer that I'd be extremely reluctant to adopt or recommend either the soil recipe or the nutrient supplementation program. The reasons are many, but to sum it up, the soil recipe will be extremely water retentive, being composed of all fine organic components. It will also break down quickly and lose its ability to retain air in volumes that maximize root health and metabolism very quickly. Replication of the mix would be difficult because more than 60% of the mix depends on ingredients of unknown and highly variable consistency.

The nutrient program in combination with the soil, will create some ammonia toxicity problems during periods of either high or low temperatures, and delivery of nutrients held in the organic molecules depends entirely on the activity of microorganisms and their ability to cleave hydrocarbon chains. This insures that nutrient delivery will almost certainly be erratic and unreliable, changing daily with microbial population shifts. The list of organic nutrients will also unnecessarily induce cyclic high levels of biotic activity in the soil, hastening breakdown of already fine particulates and further promoting soil collapse.

I'm happy for you - that you are able to find good results in your soil/nutrient program, but for those readers that are looking for advice on something that's reliable and relatively trouble free, I'd have to say that I suggest they look at something different - something without the probable complications.

Take care, RD.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Al, I know you have mentioned Dyna Grow's Pro-TeKt somewhere or the other. I wanted to thank you for mentioning that.

I was planning on looking at that at some point in the future, but just today I got an order from Dyna Grow and they included a write up on the role of silicon in plants.

Very interesting stuff. Almost makes me wonder what our container fertilization programs will look like in 10 years as our collective understanding of what plants actually take up and use increases.

At first I wondered how a container plant could possibly benefit from silicon and if it could even take it up. Imagine my embarrassment when I read this.

Here is just the abstract:

Silicon is the second most abundant element in soils, the mineral substrate for most of the world's plant life. The soil water, or the "soil solution," contains silicon, mainly as silicic acid, H4SiO4, at 0.1-0.6 mM--concentrations on the order of those of potassium, calcium, and other major plant nutrients, and well in excess of those of phosphate. Silicon is readily absorbed so that terrestrial plants contain it in appreciable concentrations, ranging from a fraction of 1% of the dry matter to several percent, and in some plants to 10% or even higher. In spite of this prominence of silicon as a mineral constituent of plants, it is not counted among the elements defined as "essential," or nutrients, for any terrestrial higher plants except members of the Equisitaceae. For that reason it is not included in the formulation of any of the commonly used nutrient solutions. The plant physiologist's solution-cultured plants are thus anomalous, containing only what silicon is derived as a contaminant of their environment. Ample evidence is presented that silicon, when readily available to plants, plays a large role in their growth, mineral nutrition, mechanical strength, and resistance to fungal diseases, herbivory, and adverse chemical conditions of the medium. Plants grown in conventional nutrient solutions are thus to an extent experimental artifacts. Omission of silicon from solution cultures may lead to distorted results in experiments on inorganic plant nutrition, growth and development, and responses to environmental stress.

I am glad you posted about it or I probably wouldn't have discovered this for some time. Now I guess I have another order to place to try this out ;-0


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Apr 1, 08 at 20:41

I'm ALWAYS happy when anyone finds something useful in a written offering I might leave. ;o) Thanks. I just received a gallon of the 9-3-6 and a gallon of Pro-TeKt yesterday. If you're vacillating over what size to buy: I've found that it (Pro-TeKt) really is extra helpful for plants in the smallish containers I often grow in, and although it's not mentioned in the abstract, to help minimize stress from temperature extremes - especially heat. It also generally just "toughens" plants to the degree that you can feel its effects when you run your hands over the foliage.

I started using it several years ago, then got away from it for some reason. I found the remnants of a quart container a couple of years ago (in winter) & started using it on the indoor stuff I have, and it reminded me of its value. I think it would be a good addition to most nutrient supplementation programs.

It can also be an excellent way to give you extra mileage from your favorite fertilizer when a lower level of N is preferred. Any time the K level is less than 4 times the P level, you can up the K with Pro-TeKt, fertilize at a reduced rate and reap the benefits of the silicon it has. This can turn a 1:1:1 ratio into something more attractive for tomatoes, because of the extra K and give us a stronger plant too, e.g. It's also a good way to reduce N levels as a way to push blooms/fruit while keeping the P & K in balance.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Hi Al,

Wanted to "thank you" for letting us know about the fertilizer from Dyna Gro Foliage 9-3-6 fetilizer. I found a website that was selling a 32 ounce at 50% off. I was so excited, that will help offset the shipping charges, (o:

Can't wait to try it!! Thanks again


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Sun, Apr 27, 08 at 12:35

Actually, I had seen a post of yours on the houseplants forum where I think "one of the extremely regular posters" I'm frequently at odds with when it comes to anything technical posted something that didn't make sense. Instead of starting a brawl, I hoped that you would read the posts on this thread & find them logical. ;o)

50% off huh? Brat! ;o)

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

I enjoy and appreciate all the knowledge shared here. Thanks Al, Justaguy, and others.

I have some more newbie questions I need help with. I apologize in advance if these have been addressed before. I did not see them in my searching.

I am using Al's mix (thanks Al) in containers. I also used it for my seed starting, along with a little commercial seed starting mix.

Here are my questions:

1. I like to use a "fertilize with every watering" program using a weak solution of water soluable liquid fertilizer. I've read that fertilizer should be applied to plants AFTER watering. I have been using water soluable fertilizer IN my irrigation water. Am I doing it wrong?

2. Last year, in my self-watering containers, I was careful to leach out salts once or twice a month by flushing each container twice, at five minute intervals. That was pretty successful, it seems. But I am still concerned about salt build up in containers over winter ( I am hoping to re-use my Al's mix for a few seasons). I've read that Osmocote can build up an excess of salts over winter, so this year I am not including Osmocote in my Al's mix.

Since there is no fertilizer in the basic mix, should I start transplants with a weak liquid fertilizer right away? What about starting from seeds? When should I start using the liquid fertilizer for new seedlings? Will they be OK in soilless mix with no fertilizer while germinating?

3. Again, concerned about salt build-up in my self-watering containers, I quit using Miracle Grow and switched to DynaGro. Further reading lead me to AlgoFlash liquid, which claims to be complete and yet have NO SALTS. Is that possible? Does that sound like a viable solution to my build-up concerns?

4. Having discovered container gardening and Al's mix last year on this site (thanks again to all), I now have a vinyl greenhouse, a full pallet of Greensmix Soil Conditioner (bark fines), and 80+ containers in the process of being planted with home grown seedlings: 20 types of tomatoes, 12 types of peppers, 11 varieties of beans, 3 type of peas, 5 types of cucumbers, 4 types of squash/melons, 4 kinds of potatoes, 3 types of lettuce, and some basil.

Does that sound excessive or just fun?

Thanks again for all your help!

Bob
wi-northernlight


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Jun 2, 08 at 17:16

I have been using (weak doses of) water soluable fertilizer IN my irrigation water. Am I doing it wrong?

The guideline should be interpreted more along the lines of suggesting that you not fertilize dry plants. Even then, the guideline is to protect the plants when there is probably already some degree of soluble salts accumulation in the soil and the application is at suggested strength. I fertilize plants with weak solutions all the time when the soil feels dry with no ill effects to date. I think I would exercise the most caution if there are ANY signs of wilt, if you know the plant is extremely dry, or if you are fertilizing at maximum recommended concentrations. If the soil feels at all damp, you're safe (as long as salt levels are not already excessive).

Since there is no fertilizer in the basic mix, should I start transplants with a weak liquid fertilizer right away? What about starting from seeds? When should I start using the liquid fertilizer for new seedlings? Will they be OK in soilless mix with no fertilizer while germinating?

There is no reason not to charge the transplant soil with fertilizer when you establish the planting. There is usually some residual fertilizers in the soil of the transplants, but I make it a point to fertilize new plantings immediately or within a day or so of establishing the planting.

When starting from seeds, it makes little difference if there is fertilizer in the soil until after the emergence of cotyledons. After that, you cannot depend on the food stored in the seed for full nutrition & you should have fertilizer available in the soil.

. . . concerned about salt build-up in my self-watering containers, I quit using Miracle Grow and switched to DynaGro. Further reading lead me to AlgoFlash liquid, which claims to be complete and yet have NO SALTS. Is that possible? Does that sound like a viable solution to my build-up concerns?

First you need to rid your mind that salts are bad, and to remove the idea of table salt from your mind when you think of salts. Salts needn't contain either elemental sodium or chloride molecules. Salts are simply a combination of a wide variety cations and anions

Incidentally, urea is a soluble substance that isnt a salt, but its solubility means it can have the same osmotic effect as salts, just as any other fertilizer and any other soluble substance. It also quickly decomposes to form a saltthe ammonium ion. Not that it's important to what you're talking about, but elemental sulfur is neither salt nor is it solublebut it oxides into sulfate, which is a salt.

If you understand a little about fertilizer, you'll see there is no advantage in the claim that a supplement has "NO SALTS". Plants cant grow without salts. The nutrients they need are salts. The dissolved ions are exactly the form they take up. As long as the dosage is controlled, there is no harm applying a salt.

Your hobby doesn't sound too excessive. I had about 20 bags of different compositions of pine bark in the garage when I bought a whole pallet this weekend. That's one ton of bark. 42 - 3 cu ft bags (it was on sale for $3.25/bag). ;o) I have to admit though, I'm using it to mulch the garden - it's beautiful stuff though.

Good luck, Bob.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Thanks Al. That clears up a few things for me.


....When starting from seeds, it makes little difference if there is
fertilizer in the soil until after the emergence of cotyledons. After that, you
cannot depend on the food stored in the seed for full nutrition & you should
have fertilizer available in the soil.


OK. I think I remember what cotyledons are, the funny looking leaves
that form from the seed, before the first true leaves are formed, right?
OK, so when I start to fertilize new seedlings, I should use a very weak
solution, right. Like say 25%?

But then, does it matter how much I use? 2 tablespoons per plant or 2 quarts per plant? Since it's all about osmosis the plant will only absorb enought nutrients to balance the nutrients in the plant with the
concentration of nutrients in the solution or in the soil,
right?

Am I on the right track here?

Thanks,

Bob -


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RE: Fertilizer Program - Containerized Plants (Long Post)

But then, does it matter how much I use? 2 tablespoons per plant or 2 quarts per plant? Since it's all about osmosis the plant will only absorb enought nutrients to balance the nutrients in the plant with the
concentration of nutrients in the solution or in the soil,
right?

Am I on the right track here?

You just went a bit off track ;-)

You should follow the label instructions for fertilizer rate or use less, but more often. This is designed to ensure a high enough, but not excessively high concentration.

Osmosis works by (stolen from wikipedia) diffusion of water through a cell wall or membrane or any partially-permeable barrier from a solution of low solute concentration (high water potential) to a solution with high solute concentration (low water potential).

In other words if you 'over fertilize' you raise the solute concentration of the growing media/water above what is in the plant itself and so the plant can't take up water or nutrients from the media. Instead the media/nutrient solution removes water and nutes FROM THE PLANT. This=kinda bad ;-)

The good news is that the makers of decent fertilizers have done their homework and their label instructions tell us what dilution to use and how often. If we follow them it's hard to go too far wrong. Using less, but more often or simply less for plants not requiring high levels of fertility can work well, but don't go over the label instructions unless you know why you are doing it and what results you are expecting.


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Jun 2, 08 at 22:46

Yes - the cotyledons are the first leaves you see after germination & usually look nothing like the first true leaves. It doesn't hurt anything to have a fertilizer charge in the soil while seeds are germinating - all greenhouses that grow from seed do it.

I'm not sure what you're asking me about how much to use. The idea (veggies & the floral containers) is to keep the soil nutrient solution in the high end of the adequacy range, and that varies by plant. You can fertilize most plantings continuously at 1/8 - 1/4 strength, even in the winter (houseplants), if you water so the soil is flushed at each watering, & 1/4 - 1/2 strength at each watering when the plant is growing robustly. That help?

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

I just thought I'd drop a comment to thank Al for his time and effort here. My Peace Lilies would like to thank you also. They are looking much better since I changed my watering habits. Most of the information you have presented is the same stuff I have heard before, but your tone and wording seem to work with me. My container planted tomatoes are doing well also. The worms are really enjoying my Persimmons *sigh*. They are the biggest tomatoes I have ever grown. I'll work on better worm control later.

Potted plants are like babies. They need small regular meals with frequent diaper changes. I've begun to view not flushing the pots as being like never letting them use the rest room. Sitting in their own filth. Well, maybe not exactly like that, but it does make a good analogy. Fresh food, fresh air, and fresh water. Duh. ;)

Anyway, thanks Al. And also to all other who contribute regularly. I read as much as I can.

One more thing Al, You mentioned somewhere about doing a bit of reading to educate yourself about plants. Could you recommend a few books? Most of what I have read is from our public library.

Thanks

Vance


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RE: Fertilizer Program - Containerized Plants (Long Post)

Potted plants are like babies. They need small regular meals with frequent diaper changes. I've begun to view not flushing the pots as being like never letting them use the rest room. Sitting in their own filth. Well, maybe not exactly like that, but it does make a good analogy. Fresh food, fresh air, and fresh water. Duh. ;)

Generally when someone else starts a thread to help others I feel free to chime in once in awhile, but try to avoid doing it to often as I do not wish to steal another's 'thunder'.

In this case I will break the rule and post in the same thread twice in the same day to simply say 'what a great way to present an idea!'

I have four kids. One is 9, two are in diapers and one is not yet born, but will soon be burning through diapers so I get the analogy. One probably could 'grow' a kid changing a diaper once every few days. The kid wouldn't be very happy, but in terms of survival it could probably be done.

As any parent would know, the diaper should be changed much more often for best results ;-)

Sometimes those diaper changes get expensive and quite inconvenient in terms of time. Still, we do it because we know it is in the best interests of the child.

It kind of sucks (especially when you have 3 in diapers at the same time!), but we simply know it must be done for best results.

This is very much the case in terms of changing potting mix (old for new) as well as flushing a container of accumulating salts in favor of new, more beneficial ones. It is true of choosing a free draining mix that can be watered more often to charge the mix with more oxygen.

Can all of this be ignored? Sure. But to the extent we wouldn't do it with our own children we *shouldn't* subject our plants to it. Certainly our kids are far more important than our plants, no question. We should go further for our kid's comfort and health than our plants.

At the same time the principle is there. We could avoid changing our kid's diaper for a week. The rash would be intense, the kid not happy at all, but it would likely survive and do 'well enough'.

Certainly we all want to do better than 'well enough' for our kids, and time/money constraints won't allow all of us to do as much for our plants as we might like, but still, the principle is there.

I think you struck gold with your question.

Plants and kids are much alike (while being quite different) and there is a huge difference between optimal and 'good enough'.


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Jun 3, 08 at 15:02

Vance - Three texts I've learned a lot from are "Water, Media, and Nutrition for Greenhouse Crops", "Growing Media for Ornamental Plants and Turf", and "Plant Production in Containers II". I still consult these texts from time to time to confirm what I'm saying is technically accurate and to make sure I'm not leaving out something important.

You might also find these of value:

David Wm. Reed. 1996. Water, Media and Nutrition for Greenhouse Crops. Ball Publishing, Batavia, IL, ISBN: 1-883052-12-2.

Paul V. Nelson. 1998. Greenhouse Operation and Management. Prentice-Hall, Inc., Upper Saddle River, NJ, ISBN: 0-13-374687-9.

Thomas C. Weiler and Marty Sailus. 1996. Water and Nutrient Management for Greenhouses. Northeast Regional Agricultural Engineering Service, Ithaca, NY, NRAES-56.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Thanks Al. I'll look for these books.

Thanks also to you, justaguy2. I've read more than one of your posts. You are quite active and appreciated.

Thanks

Vance


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RE: Fertilizer Program - Containerized Plants (Long Post)


......But then, does it matter how much I use? 2 tablespoons per plant
or 2 quarts per plant?


I was speaking of newly emerged seedlings in 32- or 74-cup flats.
What I meant here is: If I am using a 1/4 strength solution for newly
emerged seedlings, I can't over fertilize by pouring on an excess of a this weak
solution, overflushing if you will, as long as my container has ample
drainage with a fast draining mix. Is that right thinking?

My biggest problem, I fear, is that I have a tendency to water whenever
the surface is not moist. With bark fine soil-less mix under lights and
fans, that can be every day. Perhaps with a good draining soil-less mix
that is not such a problem? Is that correct?

I appreciate your comments.

Bob


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Jun 4, 08 at 16:20

If I am using a 1/4 strength solution for newly emerged seedlings, I can't over fertilize by pouring on an excess of a this weak solution, overflushing if you will, as long as my container has ample drainage with a fast draining mix. Is that right thinking?

Yes. The TDS (total dissolved solids) level and EC (electrical conductivity) of both the nutrient and soil solution will remain low enough that there should be no issue with plasmolysis (fertilizer burn - reverse osmosis) at these levels as long as you are watering correctly.

My biggest problem, I fear, is that I have a tendency to water whenever the surface is not moist. With bark fine soil-less mix under lights and fans, that can be every day. Perhaps with a good draining soil-less mix that is not such a problem? Is that correct?

At least you're not in denial. ;o) Having identified a potential cultural issue is probably more than half of what it takes to fix it. Try watering your plants well & then force yourself to wait until the first signs of wilt (unless you're dealing with plants with leathery leaves & thick cuticles) before watering again. Don't make it a habit, but this will help you with a better grasp of what the watering interval should be, even if it is variable with planting maturity and cultural conditions. It's best to water plants immediately before decreasing water availability turns to actual drought stress.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Hi Al,

I just wanted to say that I've spent hours and hours reading your various posts on soils and fertilizers, and I am MUCH more educated about gardening than I was two days ago (indeed, I think I have some information leaking out of my ears). Thank you SO much for taking time out of your life to share all of this information with us. Your posts are easy to read and well explained, and you are so patient and thorough in your answers to the many questions you are asked. Extra kudos for persevering even when people give you a hard time, merely because their regimen differs from yours. Your courtesy and good humor are a tremendous asset to these forums, and people like you make the internet a better place to be.

Warmest Regards,
Jenn


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Sun, Jun 15, 08 at 23:26

Ohh, Jenn - how nice it is to read a post like yours. The folks on this forum have been so vocal in their thanks and gracious thoughtfulness that it very often makes me blush. I really don't feel like I'm doing anything out of the ordinary - I just really enjoy the feeling I get when I think I'm helping someone ... whether I am or not! Lol ... so I hang with you guys. ;o)

I don't worry much about anyone giving me a hard time. It happens, but it's almost always from the same quarter, same poster. I know my heart is in the right place, and hopefully the rest of the forum does too, after all these years. I figure that if I keep my heart in the right place & try my best to make sure my offerings are substantive and scientifically sound, the sometimes subtle, sometimes direct aspersions will continue to fall on deaf ears. ;o)

I really hope you've found something you can use in what you've read. Your expressed kindness leaves me hoping that all your gardening efforts are increasingly successful; and if I've had any small part in augmenting that success ... with that and your thank you, I'll have found ample reward. Good luck, Jenn. Thank you.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

I've read all the pages so many times and made copious notes to myself that I have brain overload. I'm filling half wine barrels with the gritty mix. They will hold citrus and fruit trees. I think I'm supposed to blend the following into the gritty mix. Osmocote - use 1/3 cup per cu ft. and gypsum - 1/2 cup per cu ft. Then I should also use a half strength liquid fertilizer once a week. These containers will be outside all year long. Do I continue to fertilize through winter?

I was also going to try to set up a drip system so I could water all the containers at the same time. Nice summer days are under 90, usually 100 and over. If I understood that right, I should get the nozzles that give off a fine spray rather than a drip and water until I notice water coming from the drain holes.

There has been so much great advice from all the forums - thank you everyone. I just have to remember it and keep my notes straight.


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Jun 16, 08 at 21:34

Sounds like you have a good program planned. You CAN fertilize all winter if you follow your program, but the returns diminish as temperatures & light levels fall & plants take a rest. I think every 3 weeks at half strength should be all you need whenever mean temps are below 50-55*.

If you're watering with an automatic system, you should select a system that disperses water over a wide soil surface w/o wetting the foliage any more than necessary.

Good luck!

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Thanks for all the help. Once I get it all set up, I'll try my hand at taking pictures.


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Jun 17, 08 at 7:50

Great! It appears you have two attributes that are important to your gardening success - determination and enthusiasm. You'll do well. ;o)

Al


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High pH watering?

Tapla, in one of your earlier posts you mentioned using vinegar in your potions. In my neck of the woods ( Toledo, Ohio), the water is very alkaline running pH 7.7. My containerized plants do fairly well in your bark based soils, but never really take off. Do you think the high pH water could be at fault? My garden soil pH is also high about 7.7. Nothing brings it down... Alum sulphate/ sulfur doesn't change it. Adding Ironite to to garden/lawn produces no effect. Leaves seem to stay small and light green.Saw your chelated Iron formulation.Suggestions?


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Jun 18, 08 at 15:22

ZZ - Yes, I think it could be the water. You speak of alkalinity and pH as though they are the same, but they are different. Here is a copy/paste job of a reply I wrote as answer to a recent post on this forum. You may find it useful:

"When we measure pH, we are measuring the concentration of hydrogen (H+) ions in the irrigation water or soil (nutrient) solution. As a guideline, water for irrigation purposes is usually best if its pH lies between 5.0 - 7.0. The measure of alkalinity gives us the water's ability to neutralize acidity. The level of bicarbonates, carbonates, and hydroxides in water determine its alkalinity. The desirable alkalinity range for irrigation water is 0 to 100 ppm carbonates, with 30 - 60 ppm optimum for most plants.

Whenever you test the water you'll be using for irrigation, you should always include the measure of both pH and alkalinity. A pH test on its own, does not give any indication of alkalinity. Water with high levels of bicarbonates or carbonates (high alkalinity) always has a pH value >7, but water with a high pH doesn't necessarily have high alkalinity. This is a very important concept because high alkalinity exerts more significant effect on plant nutrition and the fertility of growing media than pH.

High pH irrigation water generally causes no problems as long as the alkalinity is low. Since high pH water with low alkalinity has little ability to neutralize acidity, it's effect on media pH will be minimal. Cause for more concern are situations where you must utilize water having both high pH and high alkalinity for irrigation, which will cause the pH of the growing medium to increase substantially as media ages. If your water analysis is known to be alkaline, you may need to significantly reduce the addition of compounds containing Ca or Mg because of the dilute solution of limestone in the water. The smaller the container - the more serious the issue because small volumes of soil offer less buffering to pH change. In high alkaline situations, you can often expect/experience Ca and Mg deficiencies along with micronutrient deficiencies (both real and antagonistic).

Acid forming fertilizer will not actually lower media pH as long as there is limestone in the soil - unless the soil is acidic already, but vinegar (and other acid) applications will help to neutralize alkalinity in the irrigation water, which will be helpful."

Deficiencies of Fe, Mn, Zn, Cu, B(oron), and P(hosphorous) can be created by high pH nutrient solution situations, even when the elements are technically in soil at adequacy levels, were they available. The consistently good results I and others are used to realizing in the bark-based soils we use are fair indication that something other than the soil is in play here.

Try watering a few plants with RO or distilled water for a couple of weeks & see if that makes a difference. Alternately, or on a few other plants, you might try adding a few tablespoons of white vinegar/gallon of irrigation water.

Good luck - sorry to hear you're having troubles.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Back again. The only gypsum I've found is called Soil Buster by Spectrum - says 70% gypsum. The back says: nitrogen 2%, phosphate 1%, soluble potash 1%, calcium 16.5%, Sulfur 13%, iron 2%, calcium sulfate dehydrate 70%. Is this the right stuff? Thanks again for all the advice.


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Jun 18, 08 at 22:14

Yes - it's the right stuff. Most gypsum products are about 65-75% CaSO4-2H2O. I suppose you should look at the fact that it contains a little of the primary macronutrients as a small plus.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by ang29 Seaside, OR (My Page) on
    Thu, Jun 19, 08 at 11:05

WOW! I just read through this entire thread... What great lessons for a first year gardener!

Thank you for the insight! Now I have to print and highlight!:0)


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RE: Fertilizer Program - Containerized Plants (Long Post)

Hi Al,

I also wanted to thank you for all the information you've shared on these posts. I've been reading a lot of them! It will take me a long time to assimilate all that information, but maybe one day I'll manage ;)

I have one question on the topic of fertilizers - you say "a reduced N supply will have more and better effect than the high P bloom formulas". How does one go about ensuring a reduced N supply if one is using one of the fertilizers with the average 10-1.5-7 ratio you suggested?

I don't have a fertilizer with this ratio - the ones I have are a) 6-3-6, b) 4-2.5-5.5 & c) 4-5-7. Before I go out and buy something along the lines you suggest I wanted to make sure I understand what I should be doing with it. Sorry for the ignorance - I'm just starting :)

Thanks!


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Jun 24, 08 at 16:28

Hi, Ang - I'm glad you found it interesting. I always envision 99% of the people who stumble on the thread as being bored to tears & off to find something more entertaining as soon as they get beyond the first paragraph, or so. It always pleases me to think something might have helped you/others. Thanks for your kindness. ;o)

Hi to you also, LilFG. ;o) Thank YOU for the kindness in your words, too. Much appreciated ...

How does one go about ensuring a reduced N supply if one is using one of the fertilizers with the average 10-1.5-7 ratio you suggested?

Let's imagine we're mixing suggested strength solutions of fertilizer. If you were using a fertilizer with a 10:1.5:7 ratio, you really can't reduce the N w/o reducing the other nutrients and causing possible deficiencies, so lets look at the 6-3-6 formula you have for a moment. We know that plants will use about 6 times as much N as P, so your 6-3-6 has 3 times more P than your plants need. We can dilute the concentration to 1/3 of what is recommended, and still have adequate P available. Can you already see that we can simply reduce the solution concentration to reduce N, and maintain adequate P? Where does that leave us in the K dept? It leaves us deficient in K. To compensate, we can add a liquid K supplement to bring the dosage of K up to about 4 times what P is.

So, by using only dilution, we can reduce the N and maintain adequate P, then add whatever K we need. If you KNOW you'll employ this strategy, you can also include extra K to compensate for what will be missing in the diluted solution by adding potash to the soil of whatever you're planting. If you do that, there is no need for the liquid K supplement. If you were using a 3:1:2 ratio fertilizer, you could dilute the mix to 50% recommended strength & still have adequate P levels, then use either of the outlined strategies to compensate for the lacking K. A 1:1:1 ratio, like 20-20-20, would supply adequate P at 1/6 the recommended solution strength.

Was that clear, or does it muddle things for you?

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Hi Al,
Thanks a lot for getting back to me. That was very clear and makes sense. So would you say then that with the 6-3-6 for example, the goal when reducing the N supply should be to bring the P down to a relative value of 1 (i.e. there shouldn't be more P than necessary)? In other words diluting 1/3rd as in your example is better that diluting less because then we'd have too much P? Or do slight differences not make a huge impact (e.g. ending up with relative concentrations of 2-1-2 versus 4-2-4)?

Another question occurred to me after reading a lot of the posts in this thread. I've read before that one should let the soil dry out completely before watering again. If I feed the plant when it's that dry (even at 1/4 the recommended dosage) would that cause problems? Should I instead try to feed the plant when it's still a little damp? I might have burnt a chili plant last week by some mistake like this so I want to learn how this should be done. I'm still hoping the burn is not too bad - it had a couple of new flowers this morning....oh dear!

Thanks again Al for taking the time to clarify things. It's very very generous of you :)


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Jun 25, 08 at 13:00

When reducing the N supplied, you need to determine whether P or K are most deficient after the reduction. Then, you can adjust the one that is being supplied in deficient volume. That will vary by fertilizer formula.

E.g - reducing a 1:1:1 ratio to 1/6 the recommended rate should still provide P at an adequate level, but it would supply K at only half of what it should be.

Slight differences don't make much difference when you're fertilizing with weak solutions because the EC and TDS remain low and won't inhibit uptake of water and nutrients. Plants tend to "take what they need and leave the rest" (old song lyrics), but it becomes much more critical when you're fertilizing with maximum strength solutions, when you're using a heavy soil that drains poorly, and during periods of slow growth when you're tempted to water in sips (or when it's necessary to water in this fashion to prevent root rot) and additional salt build-up in soils is the inevitable result.

It's prudent in ALL situations to provide only what the plant is using, because even elements the plant does not use makes it more difficult for the plant to absorb water and nutrients. In some cases the hi-P formulas are harmful directly by creating antagonisms of other nutrients (Fe & Mn especially). In other cases, the effect is indirect simply because they (the extra nutrients) are unnecessarily available and raise the TDS and EC levels unnecessarily high, provide no benefit, and make it impossible to adequately supply N and K w/o risking fertilizer burn.

I've read before that one should let the soil dry out completely before watering again. If I feed the plant when it's that dry (even at 1/4 the recommended dosage) would that cause problems? Should I instead try to feed the plant when it's still a little damp?

Generally speaking, fertilizing with weak fertilizer solutions is far less likely to cause plasmolysis in any degree than fertilizing at full strength - whether the plant is dry or not. Since some plants give little in the way of visual cues when they are experiencing drought stress, it's always best to be sure the plant is not completely dry when you fertilize - especially with stronger solutions. If you have any doubt, hydrate the plant and THEN fertilize.

Also, a high % of plants shouldn't be allowed to go completely dry. Veggies, your garden variety blooming & foliage plants - all suffer and are set back by any degree of drought stress, which occurs before wilting, btw. You should avoid the condition whenever possible. When soils first feel dry to you (about 40% saturation) plants can still extract an additional 10-15% of the tightly held water, so water established plantings when the soil at the drain hole first feels dry or when the wick is no longer damp. For new plantings with roots systems that have not colonized the entire soil mass - water when the soil an inch below the surface feels dry.

I would flush your chili thoroughly several times & then depot & set it on a newspaper to drain (or use a wick & wait until it gets rather dry to water again). That will help reduce the level of solubles in the soil & allow the plant to commence w/the business of recovery.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Thanks a lot Al! I understand about the fertilizers now, and I've flushed my chili plant - fingers crossed!


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Fri, Jun 27, 08 at 14:20

You're very welcome. I'm sure we're all pulling for you. Good luck!

After a thorough flushing of the soil, you should be sure to give your chili a weak dose of fertilizer at the first watering - prolly 1/4 recommended strength; and, chili's like their feet to be more toward the dry side than wet, if you don't already know that. ;o)

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Al:

You can ignore my offline email. This is the thread I was looking for! Not only do I want to thank and praise you, but in addition, the person who suggested I call my water dept to get the Ph, and more importantly, the alkalinity of my water. Wow! Very easy and informative!

I live in Lake Elsinore in So. Ca. and my Ph is 7.5-8.5 while my alkalinity is about 100. These are averages, as there are 4-5 sources for the water this dept. uses.

Now that I have that, can you advise what I need to do to adjust my mix or my ferts to comepensate? Thanks!


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Aug 18, 08 at 17:05

Man! I started this reply 3 times & kept getting distracted! ;o)

Your Ca, Mg, and Fe levels would be helpful.

Your pH is a little high (about the same as mine) and the total alkalinity is at the highest end of the desirability chart. If you don't have a ton of plants to water, I would add 2 oz of distilled vinegar to each gallon of water when I irrigate.

Here are some target ranges for irrigation water content. I hope you find it interesting:

Desirable Ranges for Problem Water Parameters
Distributed by Dr. John C. Peterson, June 29, 1990 at American Bonsai Society Symposium at Ohio State University:
�� pH: 5.0 to 6.5
�� Soluble Salts (Conductivity): 0 to l.5 mmhos per cm (1 mmho is equal to 1000 umhos)
�� Calcium: 0 to 120 ppm (1 ppm is equal to 1 mg per liter)
�� Magnesium: 0 to 24 ppm
�� Sodium: 0 to 50 ppm
�� Chloride: 0 to 140 ppm
�� Boron: 0 to 0.8 ppm
�� Fluoride: 0 to 1 ppm
�� Sulfate: 0 to 240 ppm
�� Alkalinity: 0 to 100 mg per liter CaCO3

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

I have tons of watering ... what is your next idea? Thanks! You are so cool, I'm watching everything you write on gardenweb, and I second the idea of writing a book, when you have time of course ...


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RE: Fertilizer Program - Containerized Plants (Long Post)

Al:
I've got the ca and mg levels: 53/20 ppm I will have to call them for the iron level as it is not in their online rpt.


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RE: Fertilizer Program - Containerized Plants (Long Post)

OK, the reason why the iron isn't shown is that it is too low to be measured. So, I have:

Ph 7.5 - 8.5
CA 53
MG 20
FE N/A
Alkalinity = 100

According to your range chart (very interesting, I must print it out)the CA and Mg are Ok, the alkalinity is at top of acceptable range, ph is a little high. I have many pots, in excess of 50, and use a hose to water as some of them are as large as 26" italian clay. What would you recommend to compensate for the numbers above? Thanks, you are such a treasure! I'm so excited!


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Aug 19, 08 at 20:25

Your water is pretty much the same as mine, and I have over 200 (easily) containers to tend. I guess how you approach your watering issues depends on how critical you are and your pocket book. You could build a siphon acidification set-up that will both lower pH and neutralize alkalinity, but I haven't gone that far yet. I think I would need to go that route if I wasn't so conscientious about watering and using an appropriately open soil so I get little salt build-up and upward pH creep as the media ages. My biggest problem so far has been getting Fe to my plants. I recognized deficiency symptoms for several years before I discovered an organically chelated Fe supplement formulated for soils (and water) with pH >7.0. I mix it right into my fertilizer concentrate & it gets added each time I fertilize. I do use vinegar every time I fertilize - on all the plants, and the 30 or so 'special' plants (other than Ficus) get it added more often in lesser concentrations - some daily. I can definitely tell it's helpful, because plants greened up quickly after I started including it. I'm certain it was the lower pH making many of the nutrients more readily available. I use a large pill bottle full that I estimate at 3 - 4 oz in every 2 gallons of solution.

I'll wait to see what ?s you have before I offer more. I don't have a feel for how much experience you have growing in containers, so I worry about being to simplistic or complicating things for you unnecessarily.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Al, quick question about fertilization. I've switched over to fertilizing twice a week with very weak solutions of MG 24-8-16, weather permitting. It's been quite hot the last few weeks so I haven't been doing much fertilizing but have been watering every couple of days.

Normally I would stop fertilizing in early September. I want to make sure the small conifer trees growing in the gritty mix have sufficient levels of nutrients for fall and winter without promoting unwanted late-season growth.

So should I stop the weak fertilizing in early September?

Thanks

Dave


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Aug 19, 08 at 23:07

There is lots of anecdotal stuff on the net & in print that says late applications of N will force succulent growth late in the season that won't harden off and freezes at the first frost, but I really haven't seen any difference between the plants I fertilized with 3:1:2 ratios right up until the mean temps were below 50*, and plants I was using 0-10-10 on.

While it's true that N provides the primary building block for new growth, it doesn't have anything to do with bud activation, which is photo-period and soil-temperature related. N is a critical component of proteins, which control the plant's metabolic processes, and is also an integral part of the chlorophyll molecule, thus playing a key role in photosynthesis.

When soil temps are above around 55*, the plant will use AND store N (as well as other elements). This store of fertilizer elements is especially critical when it comes time for the spring growth push and cold soils are making N largely unavailable.

For a number of years I have fertilized right into winter during periods of favorable temps with MG in either a 3:1:1 ratio (30-10-10) or a 3:1:2 ratio (24-8-16 or 12-4-8) with no ill effects. I'll continue that tack this year, but as the winter chill comes on, I'll likely turn exclusively to the Foliage-Pro 9-3-6 because of it's low urea/high nitrate content, which diminishes the possibility of ammonium toxicity @ low temps.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Well again, thanks for a great thread, Al. Funny, I have lots of spray bottles around here ( I live in SoCal, btw) because I was using them to train hybrid cats I was breeding. I always put a little vinegar in the water because it helps deter water loving cats that don't mind a squirt of plain water when they are acting up. This past weekend I reached for a water bottle to mist some seedlings I am propagating, and realized in a panic that the bottle I almost used had one tsp of vinegar in it.

I guess it wouldn't have been the end of the world now that I read your post. I have to find time to read your posts for like an hour a day to catch up...yikes!

thanks again, you're a wealth of information!
~Susan


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RE: Fertilizer Program - Containerized Plants (Long Post)

Thanks for the reply Al. I tried some of that 0-10-10 liquid fert last year. I also read many heated on-line debates about going with a 0 N fertilizer late in the season. Some authors claimed it was beneficial to the plants while others said it was a complete waste of money. I don't know if the 0-10-10 helped or not, but the firs and pines did quite well this year.

With the goal of allowing the small trees to store NPK for winter and early spring growth I'll keep fertilizing with weak MG 24-8-12 until it starts to get cold (ground temps around 55 or so) into mid-October.

I certainly don't mind fertilizing them but wasn't sure if the small trees could actually make use of fertilizer late in the growing season. Since the roots continue to grow until the ground freezes they certainly need watering but was unsure whether the roots could still absorb fertilizer effectively into October.

Thanks Al.

Regards,

Dave


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RE: Fertilizer Program - Containerized Plants (Long Post)

I've been growing in containers for years, and have everything from citrus trees to ferns and dwarf evergreens in pots. All are outdoors. So, although I am experienced, I am very new to your methods and a lot of the science is beyond me (too old to concentrate I guess) What motivates me at this point is that I have plants that are growing out of their already large pots and I am desperate for solutions other than "time to put in the ground". Your logical approach is very appealing to me and the idea that I can manipulate the size of the roots is exactly what I am looking for. I am slowly converting all of my pots to your mix. I am ready to move to ferts, and really would love your advice. I would prefer to stay simple, at least to start, (such as the vinegar idea-excellent!) and will be ordering the foliage 9-3-6, however,would like your advice on how to work with my water, hence all the measurements I obtained from the water dept.

You go for it Al! If it's over my head, I'm sure some of your other fans will totally benefit. Thanks in advance...


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Al - Fertilizer Program - Containerized Plants (Long Post)

Just another post to bring this back up to the top in the hopes that you will see it and look at my post of 8-20. Thanks!


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Sep 2, 08 at 17:07

Oh - sorry! I thought I'd pretty much covered the thought that your water isn't too much different than mine. I don't think you need to go to any kind of extremes to try to correct the water - everything seems to be reasonable or at worst, marginal. Many of us deal with water much further from ideal than yours with good success. Adding acid to neutralize alkalinity and bring the pH down to below 6.5 would be helpful, but I only add vinegar to a few plants (while they're outdoors) on a regular basis & to almost all the others when I fertilize, and my plants are all lush/green (except a couple I thought would tolerate another summer w/o repotting - oops). ;o)

I'm still not exactly sure what you were looking for - if I covered it. If you still have specific questions, I'll do my best to answer them.

Take care. ;o)

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

Well, I have come up with an idea that works really well for me - I hooked up an MG feeder, put in a few tablespoons of vinegar (with red food coloring so I can tell when it is gone) and my plants have really rebounded! My ferns are a very dark green, my trees are very dark green, one of my container ornamental cherries actually started blooming for the first time in 4 years! Really a big difference! In addition I am slowly converting everything to your mix and have had remarkable results from that as well. My dwarf prunus incisa (which was covered in brown shrivelled leaves that I removed completely) has completely releafed out, brand new bright green leaves. And the temps here have been mid-90's to hi-90's for weeks! Also, I found the perfect wick: a long pipe cleaner my grandkids use for crafts. It is stiff enough to go in easily, and drips really well. Thanks so much for all of your generosity. I am having a great time following you. Please keep posting. I read all of your posts and learn from all of them. Thanks again!


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RE: Fertilizer Program - Containerized Plants (Long Post)

Hi Al-

You provided this link in an answer to a question I had in another thread, and I have a few questions based on what I have read here, so I thought I'd revive this thread instead of starting a new one.

It looks like you switched to the Dyna grow 9-3-6 last year. Do you still use CRF in your soil mix if you are still using this fert?

Also, I have alkaline water, between 98-109ppm, depending on which facility the water is coming from, with a pH of 8.0. Will simply adding vinegar to the water, as you recommended above, solve any issues that would stem from having high alkalinity and high pH, and are there other issues I may need to address separately that would result from the high alkalinity and pH?

Did you still have problems with Iron deficiencies after switching to this new fert mix? (or do you still use the Iron chelate?)

Lastly, and this may be a repeat of a similar question somewhere else...I'll be growing tomatoes in my containers. Would you recommend the addition of the Pro-Tekt to help boost the K without increasing N to help with bloom/fruit production? I thought I may have seen you mention that.

I had hoped to try an organic route to fertilizing, Dan had some great suggestions in a recent thread on Organic Container gardening in this forum, and I may try some experimentation of my own, growing two of the same variety plants in the same soil mix, (separate containers, of course) but using two different fertilizing methods to see if there is a detectable difference.

Thanks so much for all of your help!

RTG


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Mar 10, 09 at 14:15

"It looks like you switched to the Dyna grow 9-3-6 last year. Do you still use CRF in your soil mix if you are still using this fert?"

Actually, I rarely use the CRFs at all. I like the near complete control the soluble fertilizers give me in containers. I'm pretty diligent about fertilizer applications, so I really don't need the CRFs to cover the 'in case I forget' base, or for any minor elements they might supply. I included them in the soil recipes to make it easier for others. As long as you're faithful to your nutrient supplementation program, you can easily do w.o them. If you think you'll be lax at times, I'd include them.

109 ppm alkalinity is nothing to be overly concerned about with fast container soils. It would be interesting to learn how the Ca and Mg levels are though. Alkalinity is related to pH because alkalinity (practically speaking and for our applications) determines your water's resistance to pH changes. If you have water 'A' at a pH of 9.0 with an alkalinity of 75 mg/L CaCO3, and water 'B', with a pH of 8.0 (a full point lower to begin with) and alkalinity of 300 mg/L CaCO3, it will take about 4 times as much 35% H2SO4 (sulfuric acid) to bring the water with the lower pH down to <6.0. That is just an illustration of the alkalinity/buffering relationship.

That aside - your water is better than mine, so I really doubt you'll have Fe/Mn issues if you're using either the 9-3-6 or MG. I will say though, that bark/peat soils have a potentially high Fe:Mn ratio, so applying Fe w/o Mn could easily create a deficiency of Mn. If I were in your shoes, I would do nothing until I actually saw evidence of an Fe deficiency. Then, I would acidify. Oh - the other likely cause of an Fe deficiency is too much P, which combines with the Fe to form an insoluble precipitate, so avoid the high P fertilizers - they are useless unless you are using them to supply the exact amount of P needed while intentionally (severely) limiting N.

I used this strategy last year: I fertilized with regular dosages of 9-3-6 until the plants were well established. I then cut way back on the dosage and added ProTeKt to the solution. I rather like to envision that I used the added K (and got the benefit of the added silicon) to change the fertilizer ratio to 3:1:3 from a 3:1:2. This allowed me to reduce the dosage of N (reducing vegetative growth) while still having adequate P and K.

Take care.

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by jodik 5 Central IL (My Page) on
    Wed, Mar 11, 09 at 11:11

Hi, Al! I'm not sure I responded to this thread... so, just in case I didn't, I want to say thank you... I wasn't sure my fertilizer program was correct, but I see now that I'm doing fine.

I use an all-purpose liquid houseplant fertilizer, and I add a bit of STEM. I use it all at about half strength every other time I water. Every once in a while, I use a fish emulsion liquid that I happen to have on my shelf. So far, all my indoor plants seem to be thriving.

The combination of a rather constant feeding program and the very aerated inorganic medium I now use have given me the very wonderful ability to grow healthy and beautiful bulbs and other plants! And it's all due to your teachings! So, thanks! You've made me a better gardener, and I appreciate very much that you've shared your knowledge!

A green thumb is nothing more than applied knowledge!


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Mar 11, 09 at 12:20

Thanks, Jodi. You've been a great advocate of many of the things I've said on the forums, and I'm really glad they seem to have helped you. ;o)

This thread will be cut off soon. I hope GW will allow a few more posts so I can refresh this one and repost it with a link back to this thread. Please refrain from additional posts and I'll try to attend to it this evening.

You guys are all great!

Al


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RE: Fertilizer Program - Containerized Plants (Long Post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Mar 11, 09 at 23:16

Thank you for taking the time to follow this post. Please use the link provided below if you still have interest in following the discussion.

Here is a link that might be useful: Fertilizer Program - Containerized Plants


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RE: Fertilizer Program - Containerized Plants (Long Post)

Fascinating thread and thank you!

With regard to the self watering containers (I've never seen one but was wondering if I should DIY just because it was a possibility - now I won't), but surely if you needed to wash out salts, after the water was used, instead of refilling the watering container, you could top water it till the water drained and overflowed from whereever it overflows when the tank gets over filled?

Probably not most efficient, but doing it a few times would reduce salt build up?

Ignore if this is a stupid question, since i obviously have never used one. Just thinking that if this makes sense, I may still try to make one :p


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