Fertilizing Containerized Plants IV

Let me begin with a brief and hopefully not too technical explanation of how plants absorb water from the soil and how they obtain 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 select elements in ionic form dissolved in the water, while excluding other materials like large organic molecules. Osmosis is a natural phenomenon that is nature's attempt at creating a balance (isotonicity) in the concentration of solutes in water inside and outside of cells. 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 colloidal surfaces and water vapor in soil gasses, along with the nutrient load dissolved in that water, and distribute water and nutrients throughout the plant. I want to keep this simple, so I'll 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). Deionized (distilled) water contains no solutes, and is easiest for plants to absorb. Of course, since distilled water contains no nutrients, using it alone practically guarantees deficiencies of multiple nutrients as the plant is shorted the building materials (nutrients) it needs to manufacture food, keep its systems orderly, and keep its metabolism running smoothly.

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 interference 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), a condition seen when 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 we cannot depend on an adequate supply of nutrients being supplied by the organic component of a container soil as it breaks down, is to provide a solution of dissolved nutrients in a concentration high enough that the supply remains in the adequate to luxury range, yet still low enough that it remains easy for the plant to take up enough water to be well-hydrated and free of drought stress. Electrical conductivity (EC) of, and the level of TDS (total dissolved solids) in the soil solution is a reliable way to judge the adequacy of solute concentrations and the plant's ability to take up water. There are meters that measure these concentrations, 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 'TDS' or 'EC'. Most of us, including me, will have to be satisfied with simply guessing at concentrations, but understanding how plants take up water and fertilizer, as well as the effects 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 tough, and learn the symptoms of various nutrient deficiencies - 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? It's really quite logical, so please let me explain.

Tissue analysis of plants will nearly always show NPK %s to be very close to an average 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. (I'll try to remember to make a chart showing the relative ratios of all the other essential nutrients plants normally take from the soil 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 at concentrations sufficient 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 don't often 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 3/4 to 1 tsp per gallon for best results. If you decide that is 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 plant's 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 nutrients readily display deficiency symptoms, even at normal nutrient loads.

You will still need to guard against watering in sips, and that habit's accompanying tendency to ensure 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 use a liquid fertilizer with a full compliment of nutrients and micronutrients in a 3:1:2 ratio. Note that 'RATIO' is different than NPK %s. Also note how closely the 3:1:2 ratio 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 soil's pH, so the manufacturer probably gave this some careful consideration. Also, P and K percentages shown on fertilizer packages are not the actual amount of P or K in the blend. The percentage of P on the package is the percentage of P2O5 (phosphorous pentoxide) and you need to multiply the percentage shown by .43 to get the actual amount of P in the fertilizer. Similarly, the K level percentage shown is actually the level of K2O ( potassium oxide) and must be multiplied by .83 to arrive at the actual amount of K supplied.

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 also an entirely a separate consideration from dosage. You'll 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. There are 6 factors that affect plant growth, vitality and yield; they are: air, water, light, temperature, soil or media and 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 most deficient nutrient will the plant growth increase. There is also an optimum combination/ratio of nutrients, and increasing them, individually or in various combinations can lead to toxicities and be as limiting as deficiencies.

When individual nutrients are available in excess, it not only unnecessarily contributes to the total volume of solutes in the soil solution, which makes it more difficult for the plant to absorb water and nutrients, it can also create an antagonistic deficiency of other nutrients as toxicity levels block a plant's ability to take them up. E.g., too much Fe (iron) can cause a Mn (manganese) deficiency, with the converse also true, Too much Ca (calcium) can cause a Mg (magnesium) deficiency. Too much P (phosphorous) can cause an insoluble precipitate with Fe and make Fe unavailable. It also interferes with the uptake of several other micro-nutrients. You can see why it is advantageous to supply nutrients in as close to the same ratio in which plants use them and at levels not so high that they interfere with water uptake. I know I'm repeating myself here, but this is an important point.

What about the high-P "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. Plants use about 6 times more N than P, so fertilizers that supply more P than N are wasteful and more likely to inhibit blooms (remember that too much P inhibits uptake of Fe and many micro-nutrients - it raises pH unnecessarily as well, which could also be problematic). Popular "bloom-booster" fertilizers like 10-52-10 actually supply about 32x more P than your plant could ever use (in relationship to how much N it uses) and has the potential to wreak all kinds of havoc with your plants.

In a recent conversation with the CEO of Dyna-Gro, he confirmed my long held belief that circumstances would have to be very highly unusual for it to be ever beneficial to use a fertilizer in containers that supplies as much or more P than either N or K. This means that even commonly found 1:1:1 ratios like 20-20-20 or 14-14-14 supply more P than is necessary for best results.

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.

So, If you select a fertilizer that is close in ratio to the concentration of major elements in plant tissues, you are going to be in 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 major 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 that has an impact on the reliability and timing of delivery of nutrients supplied in organic form, in container culture. Nutrients locked in hydrocarbon chains cannot be relied upon to be available when the plant needs them. This is a particular issue with the immobile nutrients that must be present in the nutrient stream at all times for the plant to grow normally.

What is my approach? I have been very happy with Foliage-Pro 9-3-6 liquid fertilizer. It has all the essential elements in a favorable ratio, and even includes Ca and Mg, which is unusual in soluble fertilizers. Miracle-Gro granular all-purpose fertilizer in 24-8-16 or liquid 12-4-8 are both close seconds and completely soluble, though they do lack Ca and Mg, which you can supply by incorporating lime or by including gypsum and Epsom salts in your fertilizer supplementation program. Ask if you need clarification on this point.

I often incorporate a granular micro-nutrient supplement in my soils when I make them (Micromax) or use a soluble micro-nutrient blend (STEM). I would encourage you to make sure your plants are getting all the micro-nutrients. More readily available than the supplements I use is Earth Juice's 'Microblast'.

When plants are growing robustly, I try to fertilize my plants weakly (pun intended) with a half recommended dose of the concentrate at half the suggested intervals. When plants are growing slowly, I still fertilize often, but with considerably reduced doses. It is important to realize your soil must drain freely and you must water so a fair amount of water drains from your container each time you water to fertilize this way. Last year, my display containers performed better than they ever have in years past & they were still all looking amazingly attractive at the beginning 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 what to use as an all-purpose fertilizer for nearly all their container plantings? If you can find it, a 3:1:2 ratio soluble liquid fertilizer (24-8-16, 12-4-8, 9-3-6 are all 3:1:2 ratio fertilizers) that contains all the minor elements would great.

How plants use nutrients - the chart I promised:

I gave Nitrogen, because it is the largest nutrient component, the value of 100. Other nutrients are listed as a weight percentage of N.
N 100
P 13-19 (16) 1/6
K 45-80 (62) 3/5
S 6-9 (8) 1/12
Mg 5-15 (10) 1/10
Ca 5-15 (10) 1/10
Fe 0.7
Mn 0.4
B(oron) 0.2
Zn 0.06
Cu 0.03
Cl 0.03
M(olybden) 0.003
To read the chart: P - plants use 13-19 parts of P or an average of about 16 parts for every 100 parts of N, or 6 times more N than P. Plants use about 45-80 parts of K or an average of about 62 parts for every 100 parts of N, or about 3/5 as much K as N, and so on.

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

Here is a link to the previous posting of A Fertilizer Program for Containerized Plants, in case you'd like to review some of the exchanges.

Another thread that has proven very helpful to a goodly number of forum participants can be found by following this link to information about How Water Behaves in Container Media. You'll find it a fairly detailed discussion about container soils.

Take care. Good luck and good growing!

Al

Al

I am gearing up to try the 5:1:1 mix this year and thought it'd be a good idea to read up on fertilizing as part of the process. :-) I have a couple of questions.

1. With houseplants, how does everyone water until it runs out more than just the little trays? It seems like a lot of work to take the plants outside or to the sink/tub every time you water. Particularly if they're larger plants. I was planning on fertilizing with every watering at 1/4 strength. But, this has me concerned that maybe I should look at a different regiment if I don't want to haul them back and forth.

2. For my (upcoming) outside containers, I was thinking of mixing in some CRF to get through the usually very wet Spring, then when the rain tapers off (or as needed) using Foliage Pro 9-3-6. But, in reading through the thread, it seems that most don't use CRF. Am I better off just skipping it, and if it rains too much, they don't get fed? Or perhaps, go ahead and feed/water even if it's raining?

Thanks for your thoughts!

Alternately, you could fertigate-flush-flush on a weekly or bi-weekly basis, or even water in sips & flush the containers thoroughly on a monthly basis.

Most people think that because a fertilizer might be soluble, that it gets flushed from the soil very quickly. Container media does retain some level of nutrients against rain in plenitude. Usually, it's only a day or two after it stops raining that you'll need to water again anyway, so I've never looked at it as that big of a deal - but there's no harm in using CRFs, other than you lose the ability to withhold fertilizer in the really hot periods.

Q - it's not clear what soil you're using, so I don't know if the Epsom salts is appropriate. You can incorporate CRFs into the soil when you establish your planting, but it's best not to incorporate if you intend to let the soil sit for an extended period or you could experience fertilizer burn.

Al

As far as the CRF, I guess I didn't really know what to expect in watering frequency. I've never used anything like the 5:1:1 before, so, learning as I go. :-) With the peat based commercial mixes I've used, I rarely have to water before mid - late June. :-)

Thanks, again!

Best luck to you guys! I'll be waiting on your results.

Al

Al

As far as "What are you doing to ensure a Ca/Mg supply?", I am posting and asking your advice as to what i need to do :). I would prefer to use up the granular MG fertilizer that i have had for a long time. I will just buy the Foliar pro (I think that is the one you recommend) with micronutrients if that will be significantly easier.

I truly appreciate all the help you provide. I am even passing along this obsession, as my 3 year old constantly asks if we can go check on "our" plants when i get home from work.

Al

For fertilizing cherry trees in Gritty mix. I was planning to mix in the same CRF and use the same MG. Also, i don't know that i can find gypsum to mix in, should i mix in epsom salts? I though i had this all straight after reading everything a few months ago but it seems like in the excitement to get everything planted, i screwed up.

I have 2 cherry trees sitting in my garage waiting to be planted and enough gritty ingredients for one of them. The other may need to go into 5-1-1 for two years or so then into gritty later on (or maybe next spring).

For the cherry in gritty mix - incorporate 2 teaspoons gypsum (easy to find at this time of year - comes in 50 lb bags or 10 lb bags wherever Espoma products are sold) per gallon of soil. Also add (dissolve) 1/4 tsp Epsom salts/gallon of fertigation solution if you're fertilizing weekly, and 1/2 tsp if you're fertilizing less frequently.

Al

The fact is, the plants you describe need fertilizer or a ready source of nutrients. We can't expect the soil to provide a complete range of nutrients, let alone an adequate measure of everything commonly taken from the soil, so NOT fertilizing assures deficiencies - not the way you;'d like your seedlings to start their life, I'm guessing. I've seen the roots of small plants wrapped around granules of CRFs and slow release products as well.

...... another myth dispelled.

BTW - you can burn seedlings just as easily by over-applying an organic source of nutrients as by over-applying synthetic sources. Ultimately, it's the TDS that's going to determine what happens insofar as fertilizer burn goes. It's possible, that if the soil was cool, what you attributed to fertilizer burn was actually ammonium toxicity; a malady that doesn't get ENOUGH blame when soils are cool and urea or organic sources of N are employed because in almost all cases, it goes undiagnosed because we aren't able to make the connection.

Al

Plants seem to be doing great except two flowerboxes of strawberries. the rest are growing great and these two seem stunted. I will post up some pictures in a separate thread.

How come those that understand science always agree that synthetics are best for container culture and understand plants can't tell the difference? Then you get these gardeners that want to look down on those that use synthetics and they do not even understand science?

I am so glad to find this sight, I have learned so much from Tapla.

I've started brewing compost tea. I use a bubbler, so I'm going for max aerobic bacteria, mainly for use on my veggies, asparagus, grapes, and lawn. I'm adding molasses (powder) as well as vinegar to the brew, as per the guidelines found in the compost forum.

Is it a good idea to used it on my container avocados? If so, diluted of full strength?

Thanks
Ken

High porosity grow media and organics do not mix.

I'm new here. I 'stumbled' across the threads on Al's 5-1-1 Mix and Gritty Mix. I read all I could for about a week. I was so excited to get started and to have received a (possible) answer to my problem of my potting mix taking more than a week to dry out and some of my very young plants starting to drop leaves. I just made my 5-1-1 mix today.

5 parts pine bark (mulch)
1 part perlite
1 part miracle grow potting mix

I did not add dolomite at the time b/c I didn't have any at the time I did this. I have since gone out and bought some garden lime(derived from dolomite). It is Espoma brand (I think and it says it's "organic").

My question is:
Can I add a little dolomite to each small pot in the first layer or so of the soil? I do have Miracle Gro liquid fert. in the yellow bottle. It is the 3:1:2 ratio although I forget the exact numbers right now. I plan on fertilizing with that.

My second question is to Al(specifically):
First off, THANK YOU for all that you have shared and continue to share and the help you give and the support you supply to those of us who 'have ears to hear' and want to 'hear' more. Can you explain (again) and step by step for me on exactly how to water my plants? Do I need to water until the water begins to run out and then water again? or water until the water begins to run out of the bottom of the plant and then stop and drain and that's it?

Thanks once again!

Dee

1) Do I need to be very careful about not getting fertilizer on the foliage when I water with the FP 9-3-6?

2) If so, what's the easiest way to water heavily foliaged or trailing plants with a watering can to fully saturate the entire surface of the mix but not get it on the foliage?

Thanks!!!

If you have time (I don't), the best way to water is:
In the first pass, apply enough water to soak the soil, but not enough that any significant volume of water exits the drain. A few minutes later, make another pass, watering again so that at least 10-20% of the total volume of water applied in both applications exits the drain. The effluent should be separated from the soil entirely so there is no possibility the salts you flushed from the soil can find their way back into the soil. Never leave the pot sitting in the effluent.

I really like the 'those with ears to hear' phrasing. It's remarkable how many have their ears closed half the time. ;-)

HM - Foliar feeding is used mainly in agricultural applications when the plant is growing so fast it can't keep up with its own nutritional needs. Usually, it is limited to one of only a few elements. Roots are by far the most efficient pathway into the plant, so much so that you could say that if your containerized plants respond favorably to foliar feeding, there was probably something wrong with your nutritional supplementation program. I know that's not the question you asked, so count it a freebie. ;-)

How important not getting fertigation solution on foliage is will vary by species and the strength of the solution. The stronger the solution, the more likely it will be to blemish foliage. Also, certain plants (those with pubescent foliage, e.g.) are prone to being easily damaged by fertigation solutions. As a general practice, I try hard to avoid it entirely.

I use a water brake made by Masakuni to water. I use it in combination with a brass fitting on the hose end that shuts water on and off with a little lever. I sort of stick it into the plant where there is no foliage and water just the soil, trying not to splash any soil onto the lower foliage.

Al

I have to admit that I've been (through total ignorance) a fertilizing-dummy. Outdoor plants have gotten time release capsules, at least in the spring.
But honestly, I'm ashamed to say, the indoor plant I've had the longest, the peace lily, hadn't been fertilized at all and I think I got it in 2009. A few months ago, before I read enough about plants, I divided and repotted it in MG soil. It took about 6-8 weeks before it decided it was going to stand back up and look alive. --You may recall that I emailed you and said I was terribly worried about it. It happened to start looking alive a day or two after my email so transplanting it into the gritty hasn't been as big a priority... which is good because it took me forever to get the ingredients and I still haven't found a bark that doesn't require a ton of sifting with great amounts of "waste." Of course, I will use the waste as mulch outside and the bark was just a couple of dollars, so excluding the time needed to get what I need, and the lack of time to finish the half-bag of unsifted mulch, it's not bad.

My recent purchase of the FP is my first houseplant fertilizer - up until the last couple weeks, everything was new in MG soil with added fertilizer so fertilization hadn't yet become an issue. Now that it is an issue, I realize how much more I have to learn.

BTW: when I transplant to gritty from an MG soil, do I fertilize with the initial, first watering or wait for the second watering?

I so appreciate your knowledge and willingness to share and educate! You have no idea how much.

It was very etiolated, so I cut the top off to root and the one leaf broke off --- but if it were a full rosette I'd have a difficult time wetting the entire surface of the soil without getting the bottom leaves wet.

Is there a trick to it, or do I just need to be super careful? I have a watering can with a narrow spout.

Of course, that's the 'by rote' method. I'm hoping you take the time to become familiar with all the reasoning that went into fertilizer manufacturers developing their 3:1:2 ratio fertilizers, and why they work so well; but if you don't, it's not the end of the world. There's always tomorrow if the mood strikes you.

Thank you for the kind words. Whenever anyone makes an effort to help, it's always uplifting to know the effort is appreciated.

The plant in the picture should soon start backbudding from around the wound where you truncated the stem. A tip - use a fine twig or toothpick to paint the fresh wound with waterproof wood glue. Cover only to the very edge of the wound, but make sure you cover all exposed cambial tissue. This stops drying of the cambium and keeps it from dying back so far from the wound site.

This is a loose nozzle from a tube of caulking. I heated it and bent it, then threaded it over the spout of my 2L watering can.

It gets me in and out of tight places with ease. If you don't have a lot of plants, you might consider Rina's idea or a contact lens bottle that jets water out in a small, directable stream when you squeeze it. At work, I use a 24 oz condiment (squeeze) bottle I bought at GFS, a food store that caters to those who buy in large portions (restaurants, institutions, parties, large families ....)

Enjoy the day, guys!

Al

I must say though that I am surprised that I'm not having to water as much as I thought. I made some batches of the mix with potting soil(for my plants that like it moist most of the time) and another batch without the potting mix. My bark seems to be mostly finely chopped/ground so I figured that would hold enough moisture without the potting mix for some other plants. I check everyday though for wetness/dryness...sometimes several times during the day, just so I can get a handle on how my plants behave in their individual mix. Thanks once again!

Harriedmom, I'm learning right along with you!!

I'd say that because of the superior aeration of both the gritty and 5:1:1 mixes, it's more than fair to say you'll need to water more frequently than when using nearly any of the more popular commercially prepared soils that have as their base a high % of fine particles - peat, compost, composted forest products .... For some reason, there is a small but vocal group of growers who wouldn't give any recognition to the attributes of any fast draining, well-aerated soils, much less one of the two I mentioned. I know I mentioned this recently - I just hope it wasn't on this thread so I come off as more redundant than I already am at times, but the few who are ever eager to point out they don't like the gritty mix because it doesn't hold enough water, are comparing it to their soils, which from the plant's perspective hold much too much water.

The gritty mix and the 5:1:1 mix hold just the right amount of water ..... to please the plant. Increasing the water retention of even the gritty or 5:1:1 mix by introducing fine particles comes at the cost of reduced potential for the plant, so comparing the convenience of the grower to the good of the plant is a little like comparing apples & oranges.

Those that aren't willing to trade a little more frequent watering for a more vital plant should probably stick with soils like MG et al. Growing well doesn't happen by accident or by luck. It comes as a result of not being afraid to do a little homework, trying something that might not seem altogether conventional at first glance, and not being put off by a little effort or inconvenience - and those are exactly the kind of people I like to surround myself with.

You guys may not see it yet, but your excitement and enthusiasm are self-perpetuating. I share it, others reading your offerings share it and in turn are motivated to follow in your tracks, which yields a second generation and a third ..... of enlivened growers.

Have fun - experiment - ask questions - help others see what you see. That's how these forums work best. If you want to share your thoughts about the contrast in what you WERE doing as opposed to how you feel about your newly chosen path, there's a thread on houseplants about MG soil where you can weigh in if you like. Telling me is like preaching to the choir. ;-)

Best luck.

Al

When I first came on this forum I would have told you that you need a bloom formula to produce fruits. Tapla and others have showed me the real science. Plants uptake nutrients at a 3;1;2 ratio. Just using less will give you what you need. After growing a while you really see whats needed or not. I am so glad to be able to find this information, it has changed my outlook on fertilizers.

Al

I'll tag on another question, if I may: lately, the weather has been HOT....over 100°F frequently,
and over 95°F consistently. We're sitting on a hot week of weather to come, and I haven't fertilized
my plants for more than a week now. How do you fertilize when the weather stays hot in your area?

Josh

I'm off on an adventure in the morning. A visit with my daughter & family, then on to Chicago for some fun at the Midwest Bonsai Show. I'll see you guys on Sunday.

Al

Safe adventures, Sir, and a happy meeting with the fam and the Bonsai Show....
need I say, take lots of pics? ;-)

Josh

So thats what makes the 3;1;3 ratio ideal for fruiting:
If your feeding a plant UP to what it can take in with the 3;1;3 ratio-Using a 1;1;1 you would be giving too much phosphorus by the time you even get close to giving all the N and K needs for full production.

Al

Josh

I have always believed it is the watering solution most important when it comes to container grown plants, right?
Then if I need to lower the pH in my watering solution to lower it from 8.5 which my water supplier provides, if the water supply also has Mg and Ca in it, then why would I still have to lime my 5.1.1 mix if the water already has a high pH and if it did provide these elements?
A bit confused on this.

There are many saying they shouldn't have lime their peat or bark mixes if they are in places like Arizona which supply hard water with a high pH already.

I don't know how to explain this to others. They think that liming their mix will only cause a further problem.
In fact, they ask me why I lime, then use vinegar to lower the pH. They tell me this is contradictory.

Thanks

Thank you!!!!!!!

"Yes, the 5-1-1 mix - due to the variation in bark pH primarily - can have quite
a low starting pH, which is why the addition of Lime is favored to bring the pH up
into the target range, while providing Calcium and Magnesium in the proper ratio.
Once the mix itself is in a range conducive to nutrient uptake, we really need only
concern ourselves with the potential alkaline creep caused by basic tap-water and accumulating
solids from fertilization. Thus, it is a good idea to test one's water and one's fertigation
solution. Indeed, in certain parts of the country, tap-water may not need to be acidified".

Liming is a very good starting point.

Mike

Marc

Thank you Al et al. for the free education and entertaining discourse.

I just received my first bottle of FP in the mail and did a little analysis to see how the contents stack up to to Al's nutrients chart. Two questions popped out at me:

1) Sulfur isn't listed as on their "guaranteed analysis" chart, however the Mg is derived from magnesium sulfate so I'm guessing that means sulfur should be present at a similar ratio to Mg. Is this about right or should I be supplementing the sulfur?

2) I understand the convention of normalizing all the nutrient ratios to the nitrogen content. I also understand the reasoning behind using the 0.43 and 0.83 coefficients for determining the P and K percentages, respectively. What I don't quite get is why we are not doing the same for N. If the FP is 6.1% NO3- and 2.9% NH4+, shouldn't those also come with 0.23 and 0.78 multipliers? That would seem to make sense to me, but I'm sure I must be wrong b/c that would completely throw FP off of the whole 10:1.5:7 ideal.

I just dosed half of my plants so I'm hoping to start maximizing my plants' potentials!

Thanks!
Ryan

As suggested above, maybe start another thread. Sorry to get off topic.

I think it is a great idea, I myself use a similar product. I certainly will never use lime. I'm in the Detroit area and our drinking water is full of minerals and has a ph of 7.8. So in general I want to minimize the amount of city water I use. I try to use rain water, but I often use it all. Many of the plants I grow are acid loving or at least like a PH of around 6.5. In this thread someone mentions using the 5 1 1 mix and all plants are doing well except strawberries. And it's probably the hard water and the addition of lime. A huge mistake! Each gardener has to know all aspects of your area. Here it is not a good idea to add lime. It will raise PH, and the water does enough of that. Any minerals are already present in the water, or can be supplemented in better ways. I add sulfur to most of my plants because of what I'm growing. I only use lime for my in ground lilacs. Al's advice is excellent, but one needs to adjust to the plant's needs. Another example if you want great tasting tomatoes do not fertilize once flowers appear, besides decreasing amount of water.. So this method would definitely produce inferior tasting tomatoes, with smaller yields. As when the plants is slightly stressed it produces better fruit, and more fruit. With fruit trees I would not fertilize anywhere near as much as suggested, and you also want to control water intake. And this is for potted trees or in ground. If you want good fruit, and not watered down yuck, you should know how to water fruit trees.
Corn can now be grown in containers and this regime would not provide enough nitrogen for a decent crop. So this info is a good start, but that is all it is, a start...

I have house plants that are over 38 years old. I bought them in the early 1970's. Mostly cacti and tropical's.
I also grow many berry plants and have fruit trees too. I'm rather new to edible landscaping but have a base of experience from growing potted plants for decades. I grow fruit in ground, raised beds and in pots.

I use Greensense Sul-Po-Mag as a soil additive in new plantings or potting soil, 0-0-23 23% K2O, 11% Mg, 22% S.
You can add to existing plantings too.
I also use as an additive Azolmite, which can be added also to existing plantings but best used in new plantings
Maxicrop seaweed is also used in existing plantings.
For new plantings I always use Mycorrhizae Fungi . Gnarly Roots is a pretty good one with 9 different species to cover all bases.
Numerous fertilizers depending on what plant, as they all have extremely different needs.
Although none of these products will help you at all if you do not know the plants you are trying to grow. None of my cacti get any of these products. Just a simple fertilizer. Good light, good soil, and knowledge of plant needs is all I need to grow beautiful cacti.