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Container soils and water in containers (long post)

Posted by tapla z5b-6a MI (My Page) on
Sat, Mar 19, 05 at 15:57

The following is very long & will be too boring for some to wade through. Two years ago, some of my posts got people curious & they started to e-mail me about soil problems. The "Water Movement" article is an answer I gave in an e-mail. I saved it and adapted it for my bonsai club newsletter & it was subsequently picked up & used by a number of other clubs. I now give talks on container soils and the physics of water movement in containers to area clubs.

I think, as container gardeners, our first priority is to insure aeration for the life of the soil. Since aeration and drainage are inversely linked to soil particle size, it makes good sense to try to find a soil component with particles larger than peat and that will retain its structure for extended periods. Pine bark fits the bill nicely.

The following hits pretty hard against the futility of using a drainage layer in an attempt to improve drainage. It just doesn't work. All it does is reduce the soil available for root colonization. A wick will remove the saturated layer of soil. It works in reverse of the self-watering pots widely being discussed on this forum now. I have no experience with these growing containers, but understand the principle well.

There are potential problems with wick watering that can be alleviated with certain steps. Watch for yellowing leaves with these pots. If they begin to occur, you need to flush the soil well. It is the first sign of chloride damage.

One of the reasons I posted this is because of the number of soil questions I'm getting in my mail. It will be a convenient source for me to link to. I will soon be in the middle of repotting season & my time here will be reduced, unfortunately, for me. I really enjoy all the friends I've made on these forums. ;o)

Since there are many questions about soils appropriate for containers, I'll post by basic mix in case any would like to try it. It will follow the Water Movement info.

Water Movement in Soils

Consider this if you will:

Soil need fill only a few needs in plant culture. Anchorage - A place for roots to extend, securing the plant and preventing it from toppling. Nutrient Sink - It must retain sufficient nutrients to sustain plant systems. Gas Exchange - It must be sufficiently porous to allow air to the root system. And finally, Water - It must retain water enough in liquid and/or vapor form to sustain plants between waterings. Most plants could be grown without soil as long as we can provide air, nutrients, and water, (witness hydroponics). Here, I will concentrate primarily on the movement of water in soil(s).

There are two forces that cause water movement through soil - one is gravity, the other capillary action. Gravity needs little explanation, but for this writing I would like to note: Gravitational flow potential (GFP) is greater for water at the top of the pot than it is for water at the bottom of the pot. I'll return to that later. Capillarity is a function of the natural forces of adhesion and cohesion. Adhesion is water's tendency to stick to solid objects like soil particles and the sides of the pot. Cohesion is the tendency for water to stick to itself. Cohesion is why we often find water in droplet form - because cohesion is at times stronger than adhesion, waters bond to itself can be stronger than the bond to the object it might be in contact with; in this condition it forms a drop. Capillary action is in evidence when we dip a paper towel in water. The water will soak into the towel and rise several inches above the surface of the water. It will not drain back into the source. It will stop rising when the GFP equals the capillary attraction of the fibers in the paper.

There is, in every pot, what is called a "perched water table" (PWT). This is water that occupies a layer of soil that is always saturated & will not drain at the bottom of the pot. It can evaporate or be used by the plant, but physical forces will not allow it to drain. It is there because the capillary pull of the soil at some point will equal the GFP; therefore, the water does not drain, it is "perched". If we fill five cylinders of varying heights and diameters with the same soil mix and provide each cylinder with a drainage hole, the PWT will be exactly the same height in each container. This is the area of the pot where roots seldom penetrate & where root problems begin due to a lack of aeration. From this we can draw the conclusion that: Tall growing containers are a superior choice over squat containers when using the same soil mix. The reason: The level of the PWT will be the same in each container, with the taller container providing more usable, air holding soil above the PWT. Physiology dictates that plants must be able to take in air at the roots in order to complete transpiration and photosynthesis.

A given volume of large soil particles have less overall surface area in comparison to the same volume of small particles and therefore less overall adhesive attraction to water. So, in soils with large particles, GFP more readily overcomes capillary attraction. They drain better. We all know this, but the reason, often unclear, is that the PWT is lower in coarse soils than in fine soils. The key to good drainage is size and uniformity of soil particles. Large particles mixed with small particles will not improve drainage because the smaller particles fit between the large, increasing surface area which increases the capillary attraction and thus the water holding potential. Water and air cannot occupy the same space at the same time. Contrary to what some hold to be true, sand does not improve drainage. Pumice (aka lava rock), or one of the hi-fired clay products like Turface are good additives which help promote drainage and porosity because of their irregular shape.

Now to the main point: When we use a coarse drainage layer under our soil, it does not improve drainage. It does conserve on the volume of soil required to fill a pot and it makes the pot lighter. When we employ this exercise in an attempt to improve drainage, what we are actually doing is moving the level of the PWT higher in the pot. This reduces available soil for roots to colonize, reduces total usable pot space, and limits potential for beneficial gas exchange. Containers with uniform soil particle size from top of container to bottom will yield better drainage and have a lower PWT than containers with drainage layers. The coarser the drainage layer, the more detrimental to drainage it is because water is more (for lack of a better scientific word) reluctant to make the downward transition because the capillary pull of the soil above the drainage layer is stronger than the GFP. The reason for this is there is far more surface area in the soil for water to be attracted to than there is in the drainage layer.

I know this goes against what most have thought to be true, but the principle is scientifically sound, and experiments have shown it as so. Many nurserymen are now employing the pot-in-pot or the pot-in-trench method of growing to capitalize on the science.

If you discover you need to increase drainage, insert a wick into the pot & allow it to extend from the PWT to several inches below the bottom of the pot. This will successfully eliminate the PWT & give your plants much more soil to grow in as well as allow more, much needed air to the roots.

Uniform size particles of fir, hemlock or pine bark are excellent as the primary component of your soils. The lignin contained in bark keeps it rigid and the rigidity provides air-holding pockets in the root zone far longer than peat or compost mixes that rapidly break down to a soup-like consistency. Bark also contains suberin, a lipid sometimes referred to as natures preservative. Suberin is what slows the decomposition of bark-based soils. It contains highly varied hydrocarbon chains and the microorganisms that turn peat to soup have great difficulty cleaving these chains.

In simple terms: Plants that expire because of drainage problems either die of thirst because the roots have rotted and can no longer take up water, or they starve to death because they cannot obtain sufficient air at the root zone for the respiratory or photosynthetic processes.

To confirm the existence of the PWT and the effectiveness of using a wick to remove it, try this experiment: Fill a soft drink cup nearly full of garden soil. Add enough water to fill to the top, being sure all soil is saturated. Punch a drain hole in the bottom of the cup & allow to drain. When the drainage stops, insert a wick several inches up into the drain hole . Take note of how much additional water drains. This is water that occupied the PWT before being drained by the wick. A greatly simplified explanation of what occurs is: The wick "fools" the water into thinking the pot is deeper, so water begins to move downward seeking the "new" bottom of the pot, pulling the rest of the PWT along with it.

Having applied these principles in the culture of my containerized plants, both indoors and out, for many years, the methodology I have adopted has shown to be effective and of great benefit to them. I use many amendments when building my soils, but the basic building process starts with screened bark and perlite. Peat usually plays a very minor role in my container soils because it breaks down rapidly and when it does, it impedes drainage.

My Soil

I'll give two recipes. I usually make big batches.

3 parts pine bark fines
1 part sphagnum peat (not reed or sedge peat)
1-2 parts perlite
garden lime
controlled release fertilizer
micro-nutrient powder (substitute: small amount of good, composted manure

Big batch:

3 cu ft pine bark fines (1 big bag)
5 gallons peat
5 gallons perlite
1 cup lime (you can add more to small portion if needed)
2 cups CRF
1/2 cup micro-nutrient powder or 1 gal composted manure

Small batch:

3 gallons pine bark
1/2 gallon peat
1/2 gallon perlite
handful lime (careful)
1/4 cup CRF
1 tsp micro-nutrient powder or a dash of manure ;o)

I have seen advice that some highly organic soils are productive for up to 5 years. I disagree. Even if you were to substitute fir bark for pine bark in this recipe (and this recipe will far outlast any peat based soil) you should only expect a maximum of three years life before a repot is in order. Usually perennials, including trees (they're perennials too, you know ;o)) should be repotted more frequently to insure vigor closer to genetic potential. If a soil is desired that will retain structure for long periods, we need to look to inorganic amendments. Some examples are crushed granite, pea stone, coarse sand (no smaller than BB size in containers, please), Haydite, lava rock, Turface or Schultz soil conditioner.

I hope this starts a good exchange of ideas & opinions so we all can learn.

Al


Follow-Up Postings:

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RE: Container soils and water in containers (long post)

Just to emphasize the value of Al's writing, I printed his paper out some months ago to keep for the future use of anyone I meet who wants/needs to garden in containers. Wonderfully enlightening and not something easily found--except on GW, of course.


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RE: Container soils and water in containers (long post)

Thanks, Al, for the info. A great post. I think it should be put in the FAQ for the forum.

A couple follow-on questions:

1. What is suitable to use as a wick? How big should it be?

2. How do you do double-potting? Do you put anything between the pots? Any tips/best practices for it?


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RE: Container soils and water in containers (long post)

Thanks Al, for posting this thread! It contains info from several different threads that I have bookmarked. Now I only have to refer to one.

I am a newbie here and am totally sold on Al's approach to soil and drainage (and one of those people filling Al's mailbox with emails!LOL). I've even started mixing my own potting mix according to Al's recipe! I have found that it drains really fast. The hardest part for me has been finding the pine bark in the right size. Most of what I have seen is either in big chunks or shreds. (Al, maybe you could post one of those pictures you sent me that shows the components you use. I printed it out when I went looking and it helped me to get an idea of what I was looking for)

Beckyed, I couldnt find any of the 100% rayon cloth that Al uses for wicks, so I bought one of those mophead replacements the kind that is made up of flat strips of absorbant material.

Lydia


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Sun, Mar 20, 05 at 12:16

Becky - If you were watering with a wick and fighting gravity, the material would need to be absorbent enough to "pull" water the distance between the source of water and the bottom of the pot. Since in this case, we're removing water from the pot, gravity is our friend and we can use almost anything absorbant that is made from something the little bugs (microbes) won't eat up too soon. The mop strands Lydia mentioned above (from synthetic mop heads) work great. I have even used braided nylon as a wick material (ties from citrus fruit bags). The material itself holds no water at all, but the capillary action allows it to drain pots nicely.

If you're using only 1 drain hole, the wick should be small enough so that there is still good drainage of the water that would normally drain without a wick. If you use more than 1 drain hole (I always do, but there really isn't much advantage except as a guard against 1 clogging, or in this case, the other is full of a wick) the wick can fill the entire hole while the other(s) provide drainage of water that would normally drain.

Next question: Double potting can be done a couple of ways. You can use a socket pot, which is a pot buried in the ground. Your pot should nest inside of the socket pot & a portion of the bottom of the socket pot and the space between the two is filled with soil. This method should drain all of the perched water every time, unless the surrounding soil is at saturation level and the water will not flow laterally.

The second method is essentially the same except that the pots are above ground. In order for this method to be effective, the depth of the soil in the larger pot (not the one you grow in) should be as deep as or deeper than the depth of the perched water in your grow pot. BUT - you can add a wick to the large pot and insure that all perched water drains from both pots.

Take note that using a wick accomplishes exactly the same thing as pot-in-pot growing. The biggest benefit of pot-in-pot (for our purposes) might lie in its temperature modifying effects. Most plants roots begin to suffer when actual root temperatures get around 90* F and shut down around 95*. If you grow in dark colored containers, they experience much higher temperatures from solar gain. Aluminum foil, white pots, or pot-in-pot growing all help to moderate the high temperatures. Shading the pots helps a great deal as well. I read that pot-in-pot growing can lower root temperatures significantly - more than 15* f. in some cases.

Remember: Wicking is particularly valuable when we are growing over-potted plants (plants in a pot that is probably too large to be healthy for the roots) and when we first plant our containers. As an example: You might have a 5 gallon bucket with 1 squash plant in it in anticipation of how large that plant WILL be by harvest, or maybe a dozen annuals in a large pot with a root mass the size of golf balls. In these instances, it's likely the soil remains too wet. Roots growing in poorly aerated media are weaker, less succulent and more susceptible to micro-nutrient deficiencies and root rot pathogens such as Pythium and Phytophthora than roots growing in well-aerated media. Anaerobic conditions (without oxygen) do not allow the roots to obtain energy from the respiratory process and encourage disease development. Energy is required for root growth, proper hormone balance and nutrient uptake as well as maintenance of cell membranes and other plant apparati needed for basic physiological processes.

So - You can grow well in a soil that wants to retain lots of water you just don't let it - you wick it. Later in the year, when roots have colonized the entire pot and transpiration is placing extreme demand on roots to provide water - remove the wick. It's almost like having the advantage of growing in a different soil without transplanting.

---------------------------------------------------------------------- - O ---------------------------------------------------------------------- -----

Hi, Lydia! Imagine meeting you here. ;o)
I don't know how to post pics on the forum, but I can mail them for another to post, if you or another reader would volunteer.

Al


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RE: Container soils and water in containers (long post)

Sorry Al, I dont know how to post pics either! Anybody?

I repotted my thyme and rosemary today. Used the above recipe. Water started draining a few seconds after I started watering. They are in 12" pots to keep them from drying out too fast. I lined the bottom with fiberglass mesh, (took the flow-n-grow things out) stuck a wick in one of the holes. I guess they work cause water is still dripping from the wick!

BTW, for anyone in the Austin area, you can get hadite at the Natural Gardener.

Lydia

Here is a link that might be useful: The Natural Gardener


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Sun, Mar 20, 05 at 17:52

I saw your other post, Lydia. You might need to water several times at first or set your pot in a bucket of water to properly wet the peat part of your soil. Peat, when dry, is extremely hydrophobic & difficult to wet.

Al


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RE: Container soils and water in containers (long post)

Al - thanks for your post. Couple of follow up questions if I may.

In summary, you are saying to:
1) don't use drainage sand, rocks, broken clay pieces, nothing
2) use only 1 or 2 drainage holes
3) use your recipe for the dirt

Is that it in a nutshell?

Questions:

1) this wick, does it just go a few inches up the dirt?
2) obviously this container needs to be off the ground, does the wick just hang?
3) for large pots (35gal) would you recommend more holes/wicks? Any other changes for large pots?
4) some guides recommend not mulching within 2-3 inches of the trunks for certain plants - would you suggest not using the pine bark for those plants?
5) I grow mainly tropicals and palms in my containers, any reason your method shouldn't be used in Florida?

I too would like to see a picture of the pine bark size (or just a description). I don't know how to post a picture, but if you email it to me, I will figure it out. I'm a gardening newbie, so a technical issue can be my "contribution"

Thanks


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RE: Container soils and water in containers (long post)

Yup Al! That's exactly what I did! I filled the pot, let it soak awhile in a big tub, then put the plants in. It worked great. Now I just hope my rosemary survives the trauma. I read that they dont like to be transplanted. Sigh!
Lydia


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Sun, Mar 20, 05 at 18:55

Klundy - I think:

Sand is useless as a drainage layer. By all means, use pot shards or something over the drain holes to keep soil from running out the holes. I use insect screening. If your intent is to reduce the amount of soil in your pot, fill the bottom with something nonabsorbant, but don't expect it to improve drainage. It will only raise the level of saturated soil higher in the pot.

Use as many drainage holes as you wish. I have wooden grow boxes that have 20 0r 30 holes in them, not necessarily for drainage, but to increase gas exchange at the rootzone. If you use a wick that sort of plugs the center hole, it's best to have other holes to drain water that would normally drain w/o the wick.

Use whatever you wish for soil, I outlined why I build mine the way I do & what I use. You decide if you would like to give it a try. I hope you do - I think you will like it.

The wick only needs to go into the pot far enough to keep it from falling out

The water needs to drain away from the pot. It can be elevated or set on the ground, where it will be absorbed. If a puddle forms around the bottom of the pot, the wick will be less effective.

"Large pots" of 35 gal isn't enough info. You need be less concerned about drainage in deep pots and more concerned about it in shallow pots. More holes or wicks will not change anything except that more wicks will remove the PWT a little faster - not much advantage there, though.

That recommendation is for 2 reasons. The first is because it can harbor gnawing rodents. The second is it makes for a wet environment against the bark where decay organisms can multiply. The eventual outcome is eventual decay of bark, followed by exposure and decay of cambial tissues, effectively girdling the tree. Roots however, are not effected, so if your tree is planted at the proper depth - with the basal flare above soil line - there is no cause for concern.

I guess I wouldn't call this my idea or method. I just adopted it from different sources, modified it to suit my needs & shared it here. I almost never use a wick because my soils drain extremely fast. I try to design every planting so, in summer, it barely goes a day without needing water. Wicks aren't necessary in that kind of soil.

I grow lots of tropical & sub-tropical trees in containers, too - probably 75 - 100 right now. For those, I use a soil that is at least 70% inorganic. I'll send the picture you asked for.

Al


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Sun, Mar 20, 05 at 19:00

Lydia - plants grown in the ground put on trunk thickness faster than containerized plants. I have several rosemary that would never make it through our winter, so I put them in the ground in spring & move them into a container for the winter. That's two transplants per year. I haven't lost one yet. Stop stressin'. It's supposed to be fun. ;o)

Al


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RE: Container soils and water in containers (long post)

Whew! That's good to know Al! I really am enjoying my new obsession, uh, hobby. But I cant help freaking out sometimes. I guess I am something of a perfectionist and get more than a little neurotic when I am trying something for the first time! Maybe I should get some xanax or something to get me through this first season, ;-). Of course, if I hadnt found Gardenweb, I would probably be a basket case and whould have given up by now. You and everyone else on these forums have been so reassuring and helpful to me. Hopefully, by next year, I should be a bit more laid back! LOL!
Lydia


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RE: Container soils and water in containers (long post)

Al
Last year I put a wik in from the top and drapped it over the the rim of a stone pot because there was only one 3/4 inch hole that kept geting clouged. The rayon wick was long and was below the bottom of the pot. It seems to have worked but it was at the end of the season and now I'm not sure .
Please comment.
Paul


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Sun, Mar 20, 05 at 21:24

I'm not sure I understand what you're saying, Paul. Did the wick come out of the bottom of the pot? Through a drain hole?

One of the demonstrations I've done is to fill a shallow dish full of water & set it on a pedestal inside of another dish. I put a wick in the water and allow it to dangle over the side of the full dish. By the time I'm done talking, the wick has removed all the water from the shallow dish (2 quarts) & drained it into the lower container.

Try it in your kitchen. Fill a shallow dish & set it next to the sink. Put a paper towel in the dish & allow it to hang into the sink, lower than the bottom of the dish. In little time, you'll see the wicking action at work & the dish will drain completely.

Al


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RE: Container soils and water in containers (long post)

The wick did not come out of the bottom but was drapped over the top of the container just as in your demo..
The container is a 4" thick stone birdbath with a 3/4' hole drilled in the bottom. The hole was so long it kept getting cloughed so I thouhgt I'd try the wick trick and it appeared to have worked because the plants lived.


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RE: Container soils and water in containers (long post)

I posted Al's soil mixture ingredients picture over in the soil, compost and mulch forum. Had to crop it a bit to keep it under the acceptable size.

Al do you use this mixture for your tropical trees?

Here is a link that might be useful: Al's soil mixture


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RE: Container soils and water in containers (long post)

Thanks for posting the pic Kevin! Not that I have any pics yet to post (but I am now thinking of investing in a digital camera!), but I wonder if you (or anybody) could post the instructions for posting pics? I cant seem to find any instructions on how to post pics here.

BTW, I also found out something else I might need to get me through this season: Ben Gay! I woke up this morning stiff and sore from all the unaccustomed activity yesterday (I am the last couch potato!). Especially in my legs from running up and down the stairs to empty out buckets of water! I thought it would be rude to just pitch it over the side of my balcony, and I didnt want to clog up my pipes with soil mixture. I didnt think container gardening would be so strenuous (cant spell). I guess it is cheaper than buying a stairmaster LOL!

Lydia


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Mar 21, 05 at 20:47

Kevin (Klundy) - those are only some of the main components of some of my soils. The dark bark at the upper right is the partially composted pine bark I would use for most container plantings that only go a year between repots or a soil change, and is what most of the forum readers would probably wish to use if they decide to build this soil. The other two bark components would be for soils I would want to last longer than a year. The one on the upper left is uncomposted pine bark and the one on the low right is fir bark. The white material is perlite.

I sent you a picture of the soil I use for trees (soil 010). It is the one with three ingredients. Equal parts of pine bark, crushed granite, and Turface - a hi-fired clay granule. There is no peat in that soil. The inorganic parts of this soil allow it to maintain good structure for a long time. It is great for all things woody and very healthy for roots. I grow lots of stuff other than trees in that soil, too.

Paul - a wick, used as you described would not normally be effective. Reason: The wick would have to pull water vertically through the soil above the perched water. Since that soil is not saturated, it would wick the water from the wick before it could drain from the pot. However, since your container is very shallow, it's possible that the soil was completely saturated. In that case, it would work. It would certainly be more effective if it was situated to hang below the drain hole, though.

Thanks for posting the pic, Kevin. ;o)

Al


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Mar 21, 05 at 21:00

As long as there aren't any big chunks of roots or rocks, Lydia, just flush it. Our bonsai group repotted 30 - 4" pot Ficus into bonsai soil last Thursday. All the old soil & debris was flushed w/o a problem. ;o)

Al


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RE: Container soils and water in containers (long post)

  • Posted by Andy_E CA 9 Sunset 14 (My Page) on
    Tue, Mar 22, 05 at 10:43

Al,

Great article, well-written and very understandable.

I would think your mix presents a challenge when it comes to repotting. Specifically, isn't it difficult to get the roots distributed throughout the new mix in such a way as to give them sufficient contact with the medium? How do you handle this?

Also, one thing that follows from your description of wicking is that terra cotta pots should provide wicking of the PWT similar to a real wick. Since they are highly porous there is an enormous amount of surface area so capillary action should be high. The evaporative nature of the process should also make the pot a bit cooler in summer.


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Mar 22, 05 at 12:56

Hi, Andy. I'm not sure I understand. Are you talking about potting up to a larger pot?

Terra-cotta does wick water away where, say plastic or ceramic pots don't, but its benefit lies in evaporation after water migrates through pot walls. With a wick you actually get a flow of water exiting the pot.

I use lots of terra-cotta & only prefer home-made wood grow boxes over it. And, you are correct in that terra-cotta pots, because of the cooling during evaporation, are easier on roots during hot weather. You'd also be surprised at how well plants do in the perforated baskets (like a colander) that aquatic plants are usually grown in. The added aeration really helps.

Al


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RE: Container soils and water in containers (long post)

Al

Home Depot has what is described as Scottsman's Landscape Mix. It mostly consists of pine bark chipped much finer that pine mulch. My question is would you recommend this for the pine bark in your recipe. Also, what are your thoughts on using silicone gels to hold water around the roots?
James


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Mar 22, 05 at 16:07

Hi, Jim. What else is in it? Any peat or sand/soil. I've bought pine bark under many names - soil conditioner, 100% southern yellow pine bark, pine mulch, 50-50 mix, etc.. If it's pine & mostly in small chunks it's probably fine. Did you see the pictures Kevin (Klundy) posted? Does it look like any of those bark components?

Hydrophilic gels or water absorbing polymers, can hold up to 150 times their dry weight in water when saturated. They're made from starches or acrylic polymers and are easily incorporated into soils. After the granules absorb water, they swell and assume a gel-like consistency. As the gels swell, they tend to maintain an open pore structure in a mix that already drains well. A mix containing even a small amount of gel will increase in volume as the gel swells. Of course, gels also increases the water-holding capacity of a soil, although a portion of the water in the gel is held so tightly that it is not available for plant growth.

My estimation is that if your soil is well aerated & drains well, they can be effective at extending intervals between watering, but if your soil drains poorly or is lacking aeration, their use will have additional adverse effects on root (and thus, overall plant) health. In other words, it's bad enough to have a soil that allows three or more days between waterings without trying to extend it to 4 or beyond.

Al


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RE: Container soils and water in containers (long post)

Lydia (Catwomn) - pics aren't allowed in the container forum which is probably why you can't find instructions. You have to go to a forum that allows pictures. Then when posting your message, you first have to click the "preview message" button. On the preview screen you will have 2 new fields. One for the file name of the picture from your computer, and one for what you want to call it in the forum. For example, Al's picture was soil7.jpg and I called it "Al's soil".


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RE: Container soils and water in containers (long post)

Al, OMG thanks for the info about flushing the water. I am scared to do anything that will cause problems in my apartment as apartment mangement types can be very venal these days and will use any excuse to charge you extra! There were some bits of vermiculite and perlite floating around but there wasnt anything big in the nursery pots. So next time I will flush and my back/legs thank you!

Also, another question about pine bark. You have said you use 1/4" to 3/8" inch bark pieces. I was wondering, for trees in bigger pots (like 15 gal or more) could you use bigger bark pieces? Once I repot my bay, I am hoping to keep it in the pot maybe 2-3 years and thought maybe bigger pieces would hold up longer. I am thinking about using a higher ratio of inorganic stuff too for better drainage (they are too heavy to put in a plant stand high enough for a wick to be much use) and using water retention crystals instead of sphagnum to keep from having to water more than once a day. What do you think?

Kevin, thanks for the info about posting pics. I wonder why pics arent allowed in here? Of course I dont have anything to post just yet, but I have a feeling that by the time the season is over, I will have invested in a digital camera.

Lydia


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RE: Container soils and water in containers (long post)

Al,
Thanks for the info. I will go to Home Depot tomorrow and see what the ingredients are for the landscapers mix.
James


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RE: Container soils and water in containers (long post)

Hi Al,

This is great information that you are sharing here. I have a few citrus trees that are in pots. They can use better drainage. I think I will stick a wick half way up the bottoms of those pots to improve the drainage once it stops raining.

Regarding the potting mix recipes, can pumice be used instead of perlite? Are they about the same thing? Will drainage be improved inside the pot if the bottom of it is also lined with an inch or two of pumice?


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Mar 22, 05 at 21:39

Lydia - The larger the container, especially taller containers, the denser the mix should/can be. The reason is the level of saturated soil is constant in all containers as long as you use the same soil. If you have a container that is deep (say 3 ft) All water will drain from the large pores (macro-pores) and the only water in the top 9/10 (approx) of the soil will be that retained in the smaller (micro) pores. A denser soil in a tall container will hold more water & still provide drainage. I think supplying this info might be starting to split hairs, though. As long as you have aeration, you can easily compensate by watering more often after roots colonize the soil.

For long term plantings, a combination of the Haydite you have along with pine or fir bark and crushed granite is a very good choice.

Paul - if you're reading this, Haydite is a suitable substitute for Turface for your tropical trees.

Al


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Mar 22, 05 at 21:43

Kal - yes, you can use pumice instead of perlite, they are close in performance, but you will see no improvement in drainage as a result of layering pumice on the bottom of the container.

Al


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RE: Container soils and water in containers (long post)

  • Posted by Andy_E CA 9 Sunset 14 (My Page) on
    Wed, Mar 23, 05 at 1:32

Al,

My comment about repotting applies whether it's potting up to a larger pot or just replacing the soil. When repotting a plant that has been in regular potting soil, the rootball maintains its own structural integrity. It "holds together". Even if I trim off a substantial portion of the existing roots around the outside, there are enough roots in contact with the soil towards the center of the ball to provide water transport to the plant until new roots grow into the new soil.

However, when I have repotted plants that were in a loose mix like you describe, the roots had nothing to hold them in place after removal from the pot. When I repotted (in a similarly loose mix) I had to work pretty hard to get the roots distributed evenly both around around the plant and vertically in the new mix. Since the old roots where not tightly integrated with the new mix I had to water several times a day at first or the plant would dry out.


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RE: Container soils and water in containers (long post)

What is Haydite and where can you buy it?


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Mar 23, 05 at 15:11

Andy - That's an interesting point. Often roots in container culture provide structure for the soil, especially when you are growing woody material. Often you'll even find badly root-bound nursery material with leaves appearing healthy enough. Frequently, if you're lucky enough to have roots colonize the container, the roots themselves will provide air pockets as the soil breaks down into fine particles & washes out the drain hole with watering. Some plants even do fairly well in these conditions. If you grow any of the tropical Ficus, you'll find this to be true.

There are several ways to tell if your plant is due for a repot, but I'll save that for another time. I don't have difficulty at repot time, Andy. Almost all my deciduous plants and perennials get bare-rooted and root pruned while dormant. Evergreens get all of the soil removed from half of the root-mass & the largest roots pruned. I hold the plant with one hand & work soil into the roots with a chopstick or nylon tool I make especially for the chore. With woody material, roots are treated much like branches - crossing roots & those growing back toward the center of the root-mass are pruned. After the first root-pruning, everything actually stays pretty neat and manageable. ;o)

Kal - Haydite is a ceramic (baked clay) particle that retains its shape and holds nutrients, water, and air very well. It is a great soil ingredient for trees or woody perennials and cacti or succulents. It is similar to another product called Turface.

Al

Here is a link that might be useful: If you follow me, I'll take you to the Haydite page. ;o)


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RE: Container soils and water in containers (long post)

First, let me thank Al for sharing his extensive knowledge about something all of us container gardeners need to know about. Second, you can post pictures on this forum, and I'll post one to illustrate.

If anybody wants instructions I'll have to email you separately because to show it on the post will produce a photo.

I have a question. I've had some plants in their soil for 5+ years. Hostas, for example, and I've never done anything to the potting soil I used (Pro-mix which has a lot of peat content). I can't repot, because I'm somewhat disabled at the moment, so am worried about my perennials (I do only balcony gardening -- no ground available). What can I do to help preserve them till I have my shoulder joint replaced this winter?

I do use Vermont Compost to replace the top inch or two, but that will do nothing to reduce the likelihood of root problems at the PWT level.

Judith


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RE: Container soils and water in containers (long post)

"Use as many drainage holes as you wish. I have wooden grow boxes that have 20 0r 30 holes in them, not necessarily for drainage, but to increase gas exchange at the rootzone."
---------------------------------------------------------------------- --
This is the concept that I am most interested in. I would think that this would be a significant advantage that container growing would have over growing in the ground. Are growth rates similar to hydroponics when you increase gas exchange at the rootzone? ...or is the soil mass too dense for it to make a significant difference? I was considering drilling as many holes as possible in the bottom of my containers yet leaving enough material to maintain structural integrity, lining the bottom of the containers with stainless mesh, then elevating the containers on wire racks to allow airflow into the bottom of the container. I would also probably add a *really thin* layer of coarse perlite at the bottom to allow more air in (not for drainage purposes, of course).

Whuddya think? Worth the trouble?


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RE: Container soils and water in containers (long post)

It appears that haydite is expanded shale--this is readily available in many areas of Texas, both in bulk quantities and bagged. Bulk is much cheaper, but you will generally have to buy at least 1/2 cu. yd. The bagged version is marketed as "Tru-Gro"


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Thu, Mar 24, 05 at 7:27

Brown. Yes, good idea I don't know if it was on this thread or not, but I recently mentioned that growing in the baskets that aquatic plants come in (esentially like growing in coarse screen on all side of the plant) yeilds amazingly healthy roots. I often buy plastic-ware at dollar stores that has hundreds of holes in it, sort of like rectangular colanders, to put plants I'm developing for bonsai in. I use such a coarse mix that the bark quickly blocks holes enough to keep soil in, but allows air to circulate in the root mass.

Remember, in container culture - the more often you have to water the more air is getting to the roots. Each watering pushes old gasses from the roots & pulls in a fresh charge of air - a very healthy state of affairs.

The more earation - the more root growth - the more vigorous the part of the plant we're most interested in - that's the top, of course.

Thank you for helping me out with the Haydite info, JD.

Al


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RE: Container soils and water in containers (long post)

Al,
Are the healthy root systems on plants grown in "colanders" due to air root pruning (in addition to gas exchange around roots)?


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Thu, Mar 24, 05 at 10:08

Technically, NO. Passive air pruning of roots simply limits their length & makes for a more compact root-ball, something often desirable in keeping plants compact (bonsai). Air pruning per se doesn't make roots healthy, but the added aeration and drainage of the container that promotes passive air pruning does.

Al


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RE: Container soils and water in containers (long post)

Al, thanks for the link to Haydite. I can get Turface locally but I am not sure about Haydite. They are much bigger than Turface too which is probably better for drainage?

Does anyone know how much Haydite cost?


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RE: Container soils and water in containers (long post)

Al earlier mentioned that dry peat is difficult to hydrate. Aquarists boil peat to wet it properly. Boiling large amounts might be difficult, and it's a little smelly, but pouring boiling water on it also works well.

I just pour boiling water into a container already containing the peat, and it sinks to the bottom in few minutes.

Hope this helps!


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RE: Container soils and water in containers (long post)

Al: do you have a post or picture of how the wick should be positioned?

I don't know if it should start about 6" down in my 12" deep pot, and then go out the base, or start maybe 8" down and lead up to the surface?

do you have a brand name for the material you have been using as wicks?

empirically, I have decided that to grow tomatoes (my current hobby/obsession) you need at least 12" of dirt below the surface of the container.....now I am starting to see from your material why this may be true!

also, I see why using some big pots last year for tomatoes, they were totally unsuccessful, and the soil seemed to go sour! I think the drainage didn't work!

Michael


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Fri, Mar 25, 05 at 18:22

No pictures, but just position it so it sticks up through the center drain hole a couple of inches into the soil and extends a couple of inches below the pot bottom. If you only have one drain hole, make sure the wick isn't obstructing it. Later in the season, if you find your soil is drying too quickly to suit you - remove the wick.

The brand name of the material I use is "Magicloth". It says, "Super absorbent man-made chamois" on the package. In the package, there are 8 large cloths about 12 x 18 and a mop. I just cut strips of the material & use as needed. The material is 100% rayon, but other brands of synthetic mops & chamois will work as well. The price sticker says $10, but you can find smaller packages or just mop-heads for much less.

Al


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RE: Container soils and water in containers (long post)

tapla, you mentioned on your first post that "It works in reverse of the self-watering pots"

I have a question, actually 2:

1) If the water has a tendency to drain with this soil, (I'm assuming the capilary action is not strong enough to bring the water level high enough to be effective, hence lower the PWT), how is the water going to be drawn up high enough for small plants to survive? Sorry, I be dumb when it comes to gardening, hence the black thumb of death!

2) Can this receipe work with vegetables in earthboxes?

Thanks for a wonderful post and discussion,
Ken


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RE: Container soils and water in containers (long post)

I have checked prices on haydite/expanded shale/Tru-Gro. Garden centers sell this product in bags for $9.99 a cu. ft., while landscape material companies sell it for $40-$45 a yard (27 cu. ft.) The landscape soil comapanies I have contacted (SBS soils and Living Earth Technology in Dallas) will sell 1/2 yard quantities, but no less. In other words, this material seems to be affordable if you are using a very small or very large quantity. For any "tweeners" this means breaking the bank for the bagged product, or being stuck with a pile of rocks. I have no idea why the price difference would be so huge--it's all the same product made right here in Dallas by TXI. In contrast, I have seen pine bark mulch both bagged and bulk for about $1 a cu.ft.

Here is a link that might be useful: TXI's Tru-Gro page


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Sat, Mar 26, 05 at 9:26

Hi, Ken. In a container, the water that is most "free" or most readily drainable, is the water in larger pores between particles in the portion of soil near the bottom of the pot. This is the water that drains when using a wick for drainage. The water that is attached to soil particle surfaces and captured in micro-pores in soil particles remains because it is too tightly held. This includes the tightly held water above the saturated layer, too.

A wick makes the free water in the saturated layer of soil "think" the pot is deeper, so it moves down the wick until only the free water is drained. The benefit of this is it drains macro-pores in soil at the bottom of the pot & makes that environment suitable for root colonization.

A container full of dry soil, with a wick extending into a water reservoir, will moisten the soil in the entire pot. Here's why: The particles of soil themselves have a great attraction for water. Where soil particles touch and the thousands of tiny pores in the organic portion of the soil are the most powerful in capillary attraction. Remember, the cells in the portion of your soil that was once living (bark, peat, etc.) were once mostly water, and water readily finds its way back into these dead cells. This strong capillarity is how giant sequoia trees pull water 300 feet into the canopy, so an 18" pot should be a snap. ;o) While the wick provides a means by which the perched water can be drained, it also provides a bridge between the reservoir & the pot. Once the water reaches the bottom of the pot, the strong capillary pull of particles will pull water through the rest of the pot.

You can do your own experiment by filling a soft drink cup with soil & inserting a wick. Allow the wick to dangle in a reservoir. Come back later, & the top of the soil will be moist. You only need to be sure the wick is absorbent enough to pull water high enough to contact the soil. This process could take an hour or several hours, but eventually, the entire volume of soil will be moistened.

If you use it, this type of watering can cause excessive fertilizer salts build-up, so the soil should be flushed regularly to remove it. Same holds true for earth box type containers.

Al


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RE: Container soils and water in containers (long post)

Hi Al

About the potting mix: many of the media here are made from Pinus radiata bark and bits.

Some break down to become very humusy and support healthy plant growth for longer than the three years. Not lush, but healthy.

Other mixes, that initially look the same, tend to dry out, keep their initial structure, grow mycellia webs, and the poor plants die young - under the same gardening conditions. They are extremely difficult to rehydrate, too. If they're dunked, mix and plant shoot to the surface like water bombs.

What would you recommend to use as a surfactant on these soils? A proprietary soil wetting agent, or something from the kitchen cupboard? Or a soaking with warm water, followed a while later with another? I haven't found a method I'm happy with yet, and hope you can advise.

For Lydia: rosemary's a bit like lavender in the way it roots in the ground. Old ones are difficult to transplant. In containers, when you are changing soil and root pruning annually, there are plenty of young roots and the shock isn't so great.


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Sun, Mar 27, 05 at 21:36

Hi, Vetivert. You're lucky to have this tree so plentiful where you are. We have very few specimens here & those that remain are infected with pitch canker, which leaves them weak, so bark beetles are also a major problem. Anyway - a story for another time.

Rewettability of container soils depends in part on our not allowing them to go below a certain threshold of soil moisture. When the water content of pine bark is allowed to drop below 35% (by volume) it becomes difficult to rewet. However, this figure depends on how advanced is the state of decomposition of the soil particles. Peat in soils shows similar characteristics. The obvious answer here is not to allow soils to dry to below these thresholds or - water more frequently. I've read your posts & know you are an experienced gardener, so it's likely this info is not helpful to you.

If you have learned to recognize the problem batches of bark, perhaps constructing your soil so it is initially higher in peat content than usual for a pine soil. The peat will act as a water retaining component in the soil. As the peat begins to break down into fine particles & wash out of drain holes in the second & third years, the cellulose in the bark should be well on the way to breakdown, making for greater bark porosity and so better wettability.

Although there are many surfactants & surfactant/polymer combinations to enhance the wettability and water-holding capacity of container media, the effectiveness of the surfactants decreases over time, requiring additional applications. I've never needed to use them, so I've done little research on their use, but of some additional consideration is the fact that some of the wetting agents are phytotoxic to woody plant materials.

Double watering is an effective way for me to be sure important plants don't end up with dry areas in the soil where portions have become hydrophobic for one reason or another. During the heat of summer, I often water containers & then, about 5 minutes later, give another thorough soaking. Another method would be to water from above, but also allow plants to remain in a saucer of water for a period to take advantage of capillarity. With this regimen, you run little risk of salt build-up.

Perhaps partially composting the bark you intend to use for a year before using it?

Don't know if there is anything here of help to you or not. Hope so, though.

Al


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RE: Container soils and water in containers (long post)

Thanks for the prompt answer, Al. Appreciated.

When the bark has been 'flaked' - as you'd use for planting orchids - that seems to break down well, with enough fines to hold moisture.

However, if the material is 'chipped' like sawdust, it has the tendency I mentioned.

Earlier today I was helping my mum in her garden. She had bought some soil conditioner a couple of years ago - 'fish and bark'. When it first came it was a rough item. No fish bones, but the sawdust was still identifiable and it was hungry in the garden. Things did not thrive.

Two years in the bag later and it's a different story. Beautiful!

So an answer might be to add some powdered blood and bone, damp well, and leave it in a bag under that patient hedge at the bottom of the garden.

Thank you again, Al, especially for the kind words. Sometimes I don't actually feel like an experienced gardener.

PS P.radiata is a principle plantation forestry species here - but the grand old 'wolfy' ones on the farms, along with the macrocarpas, are the ones with Presence.


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RE: Container soils and water in containers (long post)

  • Posted by shirl36 zone 5 Illinois (My Page) on
    Fri, Apr 1, 05 at 18:26

Al...about your soil recipe.....I am real anxious to mix up a batch of potting medium by your recipe....today I found all I needed, but have a concern about the pine bark... you say "pine bark fines".....I take fines to mean a fine texture....all I could fine was pine bark and pine bark mulch....the mulch looked to me it would work comparing it to the picture of your soil mixtures above...
The clerk did not know what I meant by fines, said the two was all they had....do I need to look further for fines?

I appreciate all your knowledge you post...it is so helpful to the novice.....I know all feels the same way....
I have printed this thread out....sit and read it word by word over and over.... Again a big THANK YOU!! shirley


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Fri, Apr 1, 05 at 20:50

Hi Shirley. I'm soo glad you find the info helpful.

Pine bark fines are like what you see in the upper right of the photo & what I usually use for plants other than trees or shrubs. They are usually partially composted. Does what you have look like the pic? If so, go to it. ;o)

I couldn't get the bark mix I've used in the past this year. The wholesaler has chosen a mix with small chunks of pine bark, other woody material, and peanut shells, instead. I'm anxious to see how it performs. Earlier this evening, I mixed (in a wheelbarrow) and bagged about 150 gallons of soil for our MG club to sell at an upcoming garden event. Tha'salotta soil! ;o)

Thanks for the nice compliment.

Al


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RE: Container soils and water in containers (long post)

  • Posted by Andy_E CA 9 Sunset 14 (My Page) on
    Mon, Apr 4, 05 at 1:26

Al,

Out here in California all I see available is redwood bark, no doubt due to the local availability. Any issues with using that instead of pine bark?


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Apr 4, 05 at 7:15

It sort of depends on the size of the particles. If it's partially composted and particle size is fairly small, it should be fantastic. Redwood bark is highly suberized & will break down very slowly. If it looks like the material on the upper right of the pic Kevin posted, you're in good shape. If it looks more like the uncomposted materials posted, pine & fir bark, the soil will be very fast & you'll need to add extra peat to hold water.

Al

Here is a link that might be useful: Some components


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RE: Container soils and water in containers (long post)

Hi y'all,

I'm baaack! Have been really busy lately and havent had time to post. But now I have gotten the hang of my software, my out of town company left sunday, and I have been running around the last 2 days getting ready to finally do some more potting. Yesterday I finished mixing up about 18 gal of Al's potting soil. And now I have a problem.

I was told that Austin has alkaline water. Al's recipe calls for adding lime, so I asked him about it. He recommended testing my water instead of the soil and if the pH is above 7 not to add lime. Well the only water pH testers I could find were for testing pools or aquariums but they tested for all kinds of other things and the range for pH was very narrow. So I just bought a Rapitest soil test kit at Lowes. (I couldnt find much info about soil test kits so I didnt know any better) The soil in my existing pots came back slightly acid, so I went ahead and added the recommended amount of lime to my mix. Then I tested that soil and it tested the same. Something made me decide to try an experiment. I put just the lime in the test vial and it also turned out the same. So I just blew $11 bucks and still have no clue about the alkalinity of my soil mix. This morning I tried a search on testing water and found some info in the Hydroponics forum (Duh!). So I went to a local hydroponics store and got a water pH tester. Low and behold, my water tested waayyy over 7! More like 9 or 10! I added some lemon juice to the water and sure enough it tested very acid so I know that this test is reasonably accurate.

So now I have 18 gal of mix that is probably way to alkaline. The various things recommended are sulphur, more compost, and more peat, but how much? The directions on the bag of lime says how much to add depending on the soil pH so I imagine the directions for sulpher will be the same. So what do I do now? Should I dump the mix I have and start over? I hate to waste it and was hoping there was something I could do to to salvage it. Help!!

Lydia

BTW, I have some advice for anyone who is gardening on a balcony. Mix small batches at a time and use gloves! It probably isnt that hard to mix a large quantity in a wheelbarrow using a shovel, but of course I dont have the equipment or room for that. I bought an 18 gal roughneck tub for mixing and storing. But I had no idea how hard it is to mix that much using just my hands and a trowel! The last batch was less than 10 gal and wasnt that difficult, but 18 gal is a whole different ballgame! Plus the hadite skinned my knuckles pretty good when digging around the sides of the tub. I had put on some rubber gloves but my fingernails popped through at the tips. So before I mix my next batch, I am gonna get some gardening gloves!


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Apr 6, 05 at 22:52

For those having water supplied by a municipality, you only need to call your local water treatment plant to find out what the pH is. They can also tell you alkalinity levels.

What have you been up to Lydia? Haven't heard from you in awhile. ;o) Sorry about your predicament. The soil will probably be OK, even if not ideal. High pH in soils ties up phosphates, iron, and manganese, but trying to micro-manage container soil pH is an exercise in futility. I guess you could add some iron sulfate, which would lower pH and provide additional iron, but that's probably going too far without testing & it's probably not worth it for a couple of bushels of soil.

The soil would be fine for most veggies and great for figs, if you have a mind to try them. You could also screen it through 1/8 inch hardware cloth & throw the fines with the lime in it away. A tablespoon of vinegar in your watering can would be ok to try as well. A drag, huh?

I hope you fare well.

Al


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RE: Container soils and water in containers (long post)

Lydia--use the mix you have. I have been adding lime to my mixes, and using commercial mixes with lime added for several years. My West Texas water is extremely hard and alkaline, probably worse than yours. I have decided not to use any lime this year, but my results have been satisfactory in the past. Don't add lime the next time you mix some potting soil and compare the results.


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RE: Container soils and water in containers (long post)

Thanks Al and jdwhitaker for your reassurance! Jeez, I know I shouldnt freak out so much but I cant seem to help it! I will go ahead and use what I have and maybe add a little more compost to the top (I cant face trying to mix it any more). I dont want to screen it cause I also have some micronutrient stuff that would probably be screened out too. Plus I dont have a soil seive. And trying to figure out how to get the pH just right without a soil test did seem futile, but I thought there was some secret recipe or technique that people with alkaline water must use.

I have some chives and thai basil, and supposedly they can tolerate higher pH levels so I took some of the mix and added some commercial potting mix I had from last year (more peat). Added some more compost and potted them in that. Didnt drain as fast, but they all need moist soil so I figured it wouldnt matter too much. Plus they are in smaller pots and would be easier to repot or replace if need be. But I wanted to get some advice before did the bay.

jdwhitaker, do you grow any acid loving plants? Do you do anything in particular with them? I have some things I want to try that like acid soil.

So okay, the bay is going into a new pot with this stuff tomorrow. And when I mix the next batch, Not only will I mix a small batch (and use gloves), I will leave out the lime and see what happens. I have a bunch of other herbs and stuff I still need to get so I should be able to compare.

Thanks again for your help guys! And now....Onward through the fog! LOL

Lydia

PS. Al, I have been running around like a chicken with my head cut off this last couple weeks. I have been trying to get my gardening program set up, and my girlfriend from Seattle was here visiting until Sun. I was gonna recruit her to help me repot the bay, but we didnt have time. Started mixing on Mon, but ran out of hadite and peat so I had to go back and get some on Tues, then went running around trying to find something to test my water/soil. By the time I got finished running around and mixing, it was too late to actually do the potting. Sigh! Not only am I obsessive-compulsive, I am also not terribly organized! LOL!


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RE: Container soils and water in containers (long post)

--jdwhitaker, do you grow any acid loving plants?

I have just planted two azaleas in large containers (half whiskey barrels) using Al's basic recipe, except I left out the lime and used expanded shale instead of perlite. This is my first attempt with an acid loving plant, and I expect good things. Container growing is an excellent way to grow these plants, since our soil is alkaline as well as our water.


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RE: Container soils and water in containers (long post)

Al, what is your opinion of professional growing mediums?

I was browsing at a store that sold Metro-Mix, which I had heard of from one of the state Extension websites. There were some types that were anywhere from 30-45% Sphagnum peat moss and/or Coir that the company considered to be their premium mixes. Their basic mix (Metro-Mix 300), though, seemed to have ingredients that would give the properties you look for in a container soil. It was 30-40% Vermiculite with pine bark listed as its second ingredient. It also contained peat moss, perlite, processed bark ash, dolomitic limestone, and a wetting agent.

Would a mix like that suffice for those of us who want to grow in containers, but don't neccessarily want to make our own mix? It was $13 for a cubic yard of the stuff. Does that sound outrageously expensive. Anyone have experience with these premium growing mediums?

Thanks for any input. Scott


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RE: Container soils and water in containers (long post)

Well, it's done! The "Bay Repotting Project" is now complete. My bay tree is now resting comfortably in Al's Mix, in a light colored pot with 3" of light colored mulch on top. I have pruned it and shaded it as best I can. I have it on a low rolling plant stand that is too low for a wick so I didnt use one.

Unfortunately Al, the bare root pruning will have to wait til the next repot, cause I couln't get it untangled enough to get all the dirt out. But I sliced it into quarters almost up to the top and spread the root tangles over a mound. Decided to give mycorrhizal fungi a try so there is some of that mixed in the soil and sprinkled on the roots.

But Lord! What a job. I feel good about getting it done, but I am exhausted! I certainly had no idea what I was getting into when I told my friends I would love to adopt their bay and thai lime trees! LOL!

Now that the bay is out of the way, next up is lemon thyme, lemon grass, mint and sage. But they will have to wait til tomorrow!

Lydia


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Thu, Apr 7, 05 at 23:11

Hi, Scott. I'm not sure what you mean by a professional growing medium. If it just says that on the bag, it doesn't mean that professionals would grow in it, but it sounds like it would be much better than some of the other mixes that are very popular with container gardeners. You can't go too far wrong if you always try to guard the porosity of your soil. I think there is little question that maintaining air in the root zone is the main hurdle for container gardeners.

"Container capacity" is the amount of water that remains in a container after it is fully saturated and allowed to drain. When containers are at "capacity", there should still be some pores that are large enough to allow water to drain from them & be replaced with air. If you buy a soil that will maintain its structure and provide some large air pores, you're on the way to some great container plants.

With a little effort, we can control amounts of water, sun, nutrients, even temperature by providing shade, but poor aeration is the most difficult condition to overcome. In short, if you think it will drain well & hold air, it'll probably be a very good choice.

Hi, Lydia. I was thinking about you while I was repotting trees earlier tonight. Glad you have that chore behind you. When you repot root-bound trees, you can make the chore a lot easier if you use a limb saw & cut the bottom 1/3 - 1/2 of the root mass off first - right through soil & everything. Then take your pruners or old wire cutters & prune out the largest roots you can reach. Then, you can poke at the remaining soil with a dull chopstick to remove additional soil.

Most plants have a relationship with mycorrhizae, some of them are host specific, meaning the particular species of mycorrhizae only forms a symbiosis (mutually beneficial relationship) with specific plants. The soil that remained on your bay tree was already inoculated with mycorrhizae, making an additional inoculation unneeded. If it wasn't, mycorrhizae is air born & will soon colonize suitable soils w/o inoculation. If you bare-root a plant during a repot, just mix a small amount of old soil and chopped up roots to the fresh soil. This is all the inoculation you'll need. Thought you might like to know that.

Take good care.

Al


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RE: Container soils and water in containers (long post)

Well, I finally got everything planted and my balcony halfway situated. Once I potted up everything, I had nowhere to put the pots! I had some plant stands but too many pots. I ended up buying a wire shelf unit to put my pots on, but then realized most of them were sun loving herbs and wouldnt get enough sun on shelves on the back wall of my balcony. So I now have herbs in pot rings, and window boxes hanging from the outside of the railing, my bay and some other things on plant stands inside the railing. And I have swept up the clutter and brought by chaise lounge back out. Sunday afternoon I just sat on my chaise lounge with a book, looking up occasionally to smile at my plants! :-)

But I digress....Al, I have been noticing that the new pots dont seem to be draining quite as fast as the first ones I potted with your mix and they seem to hold water longer. The first time I tried your mix, I used it for thyme in a 12" pot. It drained very fast and even with that flow-n-grow thingy in it, the water meter would go from wet to moist very fast (almost as soon as I stopped watering) and would go to dry within a day or so.

These new pots dont drain quite as fast and it seems like it took a week or so for them to read dry. In fact I thought my water meter wasnt working right cause they were still reading moist about halfway down (and these are all herbs that like things pretty dry). The top felt pretty dry to me so I watered them anyway. In some pots the wicks were dry, but still reading moist near the bottom.

Yesterday I drenched everything with compost tea, and let them aborb it for awhile. Today, the rosemary is still a little wet at the very bottom, but the rest of them are reading wet much higher up in the pot. One is still wet about halfway down.

None of them look like they are suffering (at least not yet), so maybe its not that big of a deal (and I am not freaking out this time LOL!), but I was just wondering why the water retention and drainage would be different. I used the same recipe and the same batch of mix. Is this a PWT thing (new pots are all 8" and rosemary is in 12"). If so, why the wicks would be dry but the soil still moist?

Another thing I noticed was that this second bag of pine bark I just bought seems to have a lot more variation in the size of the pieces than the last batch. Some of them are pretty big. Will that cause a problem with drainage eventually? You said that large particles mixed with smaller particles will fill in the spaces between the larger ones? Right now I have only used it for the mix for my petunias in a windowbox, (not the pots that I was talking about in the previous question), and since they are annuals, I am not gonna worry about it now, but wondering for future reference. You have said you use pieces that are 1/4" - 3/8". Even with the picture, I have trouble judging the right sizes (my visual-spacial skills suck!). I am thinking about getting a soil seive, cause figuring out size of the bark pieces is the hardest part for me. What do you think?

This is nothing urgent (cause everything looks okay so far), its just "One of those things that make you say hmmmm..."

Lydia


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Apr 19, 05 at 16:15

Container gardening isn't like baking a cake, where everything has to be measured carefully, or you run the risk of it flopping - so relax. I think you're stressin' again over naught. ;o)

I notice frequently, that two bags of bark are often quite different in their water holding ability. Those bags whose contents are a little further along in the composting process usually hold more water than bark that is uncomposted or slightly composted. Also, both peat and pine bark become hydrophobic (water-repellent) when moisture contend drops below about 30%, so it is important the initial watering is a very good soaking.

The wick will only remove loosely held water. That is, water held in macro-pores or the bigger potential air spaces. Even with a wick, poor container soils can retain enough water in micro-pores to cause root problems. The smaller the soil particulate size is, the more water the soil will retain and the more tightly it is held.

About the soil sieve - You don't need it unless you grow lots of stuff in small containers (1 or 2 cups up to a quart). I do sieve all my bonsai soils, but don't bother with it for my garden plantings. You're making this too hard, Lydia. ;o)

Take care, my friend. Talk to you soon.

Al


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RE: Container soils and water in containers (long post)

Well thats good to know, cause I dont want to have to repot anything before next year! I guess I will be glad of the extra water retention when summertime hits!

Thanks,
Lydia


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RE: Container soils and water in containers (long post)

hmm, here's a part of the original post I don't get:

"If we fill five cylinders of varying heights and diameters with the same soil mix and provide each cylinder with a drainage hole, the PWT will be exactly the same height in each container. This is the area of the pot where roots seldom penetrate & where root problems begin due to a lack of aeration."

Most plants I buy or grow have holes in the bottom of the containers for drainage and I typically see a large volume of roots in the soil at the bottom. So much that they swirl around and seem to have no problem at all surviving in the area called the PWT.

So, why the statement about roots seldom penetrating into this area?


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Thu, Apr 28, 05 at 6:53

The PWT is still there, but as roots colonize the entire container, the plant or plants use the water contained in the PWT rapidly enough that it doesn't present a problem. With small plants and undeveloped root systems it can be a problem.

Perhaps I should have written "... where roots are often reluctant to penetrate ..."

I recently purchased a "potting soil" to use in a demo/talk about container gardening. I filled an 8 inch pot & allowed it to drain for a full day. When I dug down into the soil, I discovered it was fully saturated so that water would actually puddle in a cone shaped hole at a depth of only 1-1/2 inches from the soil surface. This is the area I was referring to, but you are correct, this does not occur in all soils. I'll change the wording if I post or share the article again. Thanks. ;o)

Al


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RE: Container soils and water in containers (long post)

Hi all, I am new here (it's been a couple of years since I was on here) and getting ready to start gardening on my new balcony. I've read through the post and appreciate learning about the science behind the drainage, etc.

My question is, I went out to Home depot and Walmart and can only find some of the ingredients for the soil mix. I couldn't find "pine bark fines" but they did have soft-wood mulch. Is this the same thing? If I can't find the bark can I use something else? Also, I couldn't find the "controlled release fertilizer". Is there another name for this? And also, the micro nutrient powder. Is there another name for this?

I don't know if, in the States, you have this brand of mix that I was looking at but it was called a professional mix and contained sphagnum peat, perlite, lime and controlled release fertilizer. Don't know if this would be comparable to your mix as it didn't say how much of each was in it. It was $9.37 (Cdn) for 2.5 cu.ft. I know it isn't very economical.

Any suggestions would be appreciated. Nancy.


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Thu, Apr 28, 05 at 20:23

Hi, Nancy
Wood mulch is a poor choice as a container soil component. Conifer bark has a Carbon to Nitrogen ratio of about 300:1, while wood mulch products have a C:N ratio of around 1,000:1 - problematic in containers.

I've used fir, hemlock, and pine bark in soils, all with very good results. Often, conifer bark is sold as mini nuggets or soil conditioner. In our neck of the woods, I've found it at Meijer and Menard's, as well as at wholesale nursery suppliers and some local nurseries. If you send me an e-mail, I'll send a pic of what to look for. Partially composted is best, but if you can only find it uncomposted, that will work fine, too. Buy some extra (if you can find it), poke a hole in the bag & wet the contents. By next year it will be partially composted.

The controlled release fertilizer (CRF), or timed release, is sold under various trade names, but "Osmocote" is probably the most recognizable name over here. I'm betting you guys have a similar product if not Osmocote. The CRF isn't really necessary. You can do just fine by fertilizing with your favorite concoction, but it is pretty important, for best plants, to get something with the minors (micro-nutrients). I use a Schultz soluble product called Micro-max Granular nutrients. It is very good for plant health. It is quite expensive, though. I think I paid about $75 US for a 50 lb (23kg) bag, but it goes a long, long way. If you can't find fertilizer with the minors in it or the micro-nutrient powder (in small packages) you could add a small amount of composted manure. I used to do this, but found it a source of weed seeds & it usually slows drainage.

None of this stuff is so absolutely necessary that you can't grow without it. If all you can get is the peat mix, just use it - millions have used it for years. Maybe add a little extra perlite. Keep your eyes peeled for the pine bark though, so you can at least try it some time soon. I'm very sure you will not want to grow in peat based soil again. I have sought out sources for dozens of different components for the various soils I build, but I have settled on pine bark as the best choice for the primary organic component of most of my soils. ... hope you eventually find it. ;o)

Good luck.

Al


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RE: Container soils and water in containers (long post)

Al, I think you may have just answered my question in the post above this one, but what about using 'non-commercial' wood mulch i.e. going out to the forest and collecting some nicely composted wood from a rotten log?

Alternatively, what about a)conifer forest litter (partially rotted needles, bark, leaves etc) or squirrel feeding sites (chewed up cones)?

Would rather go for a hike than buy stuff out of a bag..

Thanks, G


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Fri, Apr 29, 05 at 17:36

Hi, G.
If it was my own soil, I think I would skip the rotted wood, pine needles, and leaves. The rotted wood, if you can harvest it the way I think you're thinking, is probably too advanced in its state of decay to dependably hold its structure through a full growing season. The leaves would probably compress quickly, slow drainage, and reduce aeration, and the pine needles, though they might retain their shape for a season, would offer little in the way of aeration. Some uniformity in particle size and an irregular shape are good physical characteristics of container soil particulates.

If you have any of that extra energy to spare, how about collecting an extra bag or two of the squirrel pine cone chewin's for me? I think they would be superb as a container soil ingredient, though a little tedious to collect. ;o)

Al


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RE: Container soils and water in containers (long post)

Heh, actually, the squirrel chewin's are the easiest thing to collect, provided you can find them. We used to call them 'squirrel's garbage heaps' when we were kids, and they are literally a big pile of chewed up cone scales, often on an old stump. I think the ones we used to see in BC were mostly douglas fir cones chewed up by red squirrels (the little guys). I'm in Alberta now and it's a little farther to the bush, but I'm going to keep an eye out when I'm biking.

G


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RE: Container soils and water in containers (long post)

Al, thank you for this very interesting subject, I read everything about how water operates within container soil, and I love the science of it!

I hope you can help me with my tomato plants, I am new to gardening in general but I have a dozen heirloom tomato plants that are about to be hardened off and go outdoors in containers.

I was going to buy 12 of those rubbermaid totes for containers, but after reading your info, thought they would be more wide than high, when taller containers would be better. I was going to use 18 gallon totes. But now, to get the depth, I will look for wastebaskets or something, because they would be deeper. If I use taller containers, which should provide more available soil to the roots as you said, would I still have to stick with 18 gallons or could I go a bit smaller?

Next question, before I read your posts, I bought bags of "container mix," to put my plants in. The ingredients listed are organic compost, spaghnum peat and/or composted bark, perlite, slow-releasing plant food and a wetting agent that allow the soil to hold water. But it doesn't say how much of each ingredient is in it. The main problem is of course, that the particles are not like your home made mix at all, no large particles, just a fine soil. It does drain quickly in the small pots I'm using now. When I transplant to the larger containers, would it improve the quality of this mix, IF I added a larger amount of pine park mulch as is in your recipe? From what I understand of it, this may not be a good idea because I'd be mixing small particles with large, instead of all uniform size particles... If adding the pine bark isn't a good way to go, I guess I'll just use the container mix, I bought lots of bags as the nursery they were from went out of business and I got them at a good price.(2 cu. ft. bags).
Hope you can help me, thanks again for the neat info.
Cheflara


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Thu, May 26, 05 at 9:56

Shallow containers are fine to grow in, but you just need to watch how you water them. Wicking is very effective on removing the saturated layer from shallow containers, but I wouldn't call your 18 gal selections too shallow anyway. I guess what I would suggest is: Initially, make several drain holes in the container bottom by melting them through (this makes a stronger hole that drilling) with a heated nail or a soldering iron. Insert a wick through the drain screen, up into the container at least 3 inches. This will help drain the lower part of the container. After your plant matures, you may find it needs the extra water the wick(s) remove - simply remove them. If you decide to use waste baskets, remember that your 'maters will produce lots of foliage, which will act as a sail. Your waste baskets could topple easily with stem breakage the result, so guard against toppling.

Much of what I offer in these forums are suggestions to improve growing techniques. Because I offer a recipe to a mix that is far better than commercial mixes for container gardening, it doesn't mean that you can't grow in another mix. I just don't happen to like the drainage/aeration of commercial mixes in the long haul. Initially, they seem fine, but as the composted products & peat break down, they cannot help but have a detrimental effect on drainage. I keep harping on drainage, but we should pay closer attention to adequate drainage/aeration than any other aspect of container culture. It is the key that unlocks the entry door to good container plants. This is especially true of beginning container gardeners. Good drainage has a tendency to forgive overwatering sins, while slow drainage magnifies them.

If you can find pine bark in the appropriate size, it would be an excellent idea to mix it about 1:1 or even 2:1 with what you have. Add about 1/3 cup garden lime to each cu ft of soil. It adds valuable calcium.(I bought 30 cu ft of bark in appropriate size this spring for my containers and repots. I went back for 50 more bags just this week to use as mulch on my gardens, and the size of the pieces had changed. They were OK for mulch, but much too large for containers.)

Catchy name, Lara. You have me wondering if your name is Lara & you're a chef or if it's a play on the name of the schefflera plant?

Al

Here is a link that might be useful: some soil components


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RE: Container soils and water in containers (long post)

Al, thanks for your help with my tomato/container/mix questions! This is great, I can't wait to get my plants in larger containers and outdoors. I didn't think about the tipping factor in using wastebaskets instead of totes, so I'll go with the totes, a cheaper way to go anyway I think.

I'll get some wicks for the totes, and some lime too. Along with these, I'll be off to find what seems to be, according to many above posts, the rather elusive pine bark mulch.


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schefflera, cheflara, tomayto, tomahto

Al, to your last question, I use cheflara as a play on the schefflera plant,- it's a simple yet beautiful plant I think. I'm not a "Lara", but enjoy cooking!


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RE: Container soils and water in containers (long post)

Very interesting discussion. I'm a visitor from the Orchid Forum and we grow a majority of orchids in bark and spaghnum, sometimes with the addition of sponge rock (perlite). Although a different root system it gives thought as to how well the media actually dries near the bottom of the pots. Many of us grow in baskets and bare root. Retaining moisture, for any length of time, is death to most orchids. The orchid mixes sold in stores sound very similar to your homemade mix. The bark mixes do not contain the spagh, which we add separately if needed. It makes me think that an orchid type mix might work for my regular container plants. Very good discussion and explanation. One question. If the bottom of the pot remains damp, why isn't the moisture absorbed by the dry media above? I understand the point about gravity, but just as a dry sponge touching a wet puddle, the water is absorbed upward. Why wouldn't the soil above absorb the wet below?
Jane


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RE: Container soils and water in containers (long post)

Great Thread.... I got here from Tomatoes and stayed all night. I will be potting up a few more now with experimental wicks and coarser mixes for a comparison. I have witnessed the PWT waterlog especially in older mixes from last years pots, so wicking sounds like the cure. And I have ammended my garden with pine bark (once through the shredder) for years with great results. I'll be adding it to some container maters tomorrow. Thanks again.


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Jun 1, 05 at 16:02

Sorry it took awhile to get back to this thread. I was at the World Bonsai Conference in Wash DC for nearly a week. It was wonderful - saw the National Arboretum, too.

Jane - the height that water can be drawn upward by capillarity is related to the size of particles and the size of the pores in and between particles. Your orchid mix holds (almost) no water in the macro-pores (the pores between the soil or media particles), only in the micro-pores of the particles themselves. Soil composed of fine, irregular sized particles has fewer, sometimes almost no macro-pores, so holds much more water. How high the saturated water column (PWT) in a soil will be is determined by a sort of antagonistic relationship between gravity & the capillary pull of the soil. When the upward pull of capillarity = the downward pull of gravity, the macro-pores make the transition from being occupied by water (in the lower parts of the container) to being occupied by air (in the upper parts).

Now: IF you were to put an orchid pot in a container of water 1 inch deep, the water would move upward through the media from micro-pore to micro-pore, eventually saturating the individual particles at the pot top, but (nearly) no water would occupy the large pores (macro-pores) between soil particles.

The direct answer to your question is: Capillarity pulls in all directions, not just up. If the bottom of the container is damp, and capable of holding more moisture, it is trying to absorb more water, just like the soil particles above, but it has the added help of gravity, so the water stays put. Now, set the pot in a container of water container so the bottom of the soil is completely saturated and the capillary pull of the lower soil is negated (satisfied, so to say). This allows the now stronger capillary pull of the soil above to defy gravity and pull water upward. The reason you don't see it working is: you water & make the media damp, but not saturated. The capillary pull is stronger than gravity so all the particles hold on to their water. Again, if you were to saturate the bottom particles, the surplus water will move upward.

I use huge amounts of fine fir bark in 1/8 to 3/8 size in my bonsai soils. It is a great component & lasts longer than pine bark. Its drawback is its expense, & depending on where you live, its availability. I had a message in my e-mail from a friend who was just in Chicago, saying he had picked up enough to last me through next years potting - made me very happy. ;o) It's probably going to drain too quickly for the taste of most container folks if used in soils, unless you amend it heavily with other stuff - then what's the point? ;o)

Good luck - glad you dropped by.

Al


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RE: Container soils and water in containers (long post)

Thank you Al. What a fascinating discussion. I printed out this entire thread to read it more carefully. It certainly clears up many questions I've had related to watering.
Great Work!

Jane


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RE: Container soils and water in containers (long post)

Just did a search on this forum for "soil" and this thread was first--and what a thoughtful discussion it is! And in the nick of time, as I'd potted some small annuals in a saucer-shaped pot, after carefully poking the drain holes into it, only to discover today that the soil was awash.

"Did they revoke the laws of physics?" I asked my sister. This well written description of gravitation flow potential and capilarity has restored my faith in science. I just tucked two wicks into the pot--we'll see how it goes.

Thank you, Al/Tapla and the rest of the contributors to this discussion!


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RE: Container soils and water in containers (long post)

Al, I took your advice and used a variation of your pine bark mulch and soil mix I already had, put in the wick in the bottom of 8 totes and all I have to do is add the lime.

My 8 heirloom tomato plants adjusted to the soil very well.
My daughter saw a bloom on one of them today. It really helped cost-wise, because it stretched the use of my container mix. I have bags of pine bark mulch(mini nuggets was the best I could find in suggested particle size)and the container mix left over I can use for other projects. Looking forward to the first fruits!
Anyone else out there using Al's soil and how are your plants doing, if so? Now if I can just keep the birds and the critters away.


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RE: Container soils and water in containers (long post)

Al, thanks for all the knowledge you have shared. The wick is a brilliant idea that have never seen before. A couple of questions if you are still following this thread.

Have you seen any research comparing the rate at which sphagnum peat breaks down vs. pine bark? If pine bark is so superior in this respect, why are the U.C. and Cornell mixes heavily reliant on the peat? Why is peat so predominantly used by commercial growers even though it is relatively expensive? I know the use of pine bark has grown significantly because it is a cheap and abundant byproduct in certain areas of the country, but I would still guess that the overwhelming majority of commercially grown plants are in predominantly peat media. Why? Also, most everything I could dig up on peat mentioned its slow rate of decompositon as an attribute. How fast does it actually break down in a container?


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Sun, Jun 26, 05 at 15:07

Peat is mainly cellulose, while bark products are a mix of cellulose, lignin, and contain good amounts of suberin, a lipid that inhibits microbes in their cleaving of hydrocarbon chains. I can't quantitatively say how quickly peat breaks down, because it depends on a number of factors, among them are temperature, moisture content, soil N levels, the decomposition rate of the other soil components, available O2 (a condition of aeration or soil porosity) etc. I can say that it breaks down faster than conifer bark products. In support of this, I would relate a couple of anecdotal observations that may be interesting. First, soils that I have used in the past that were peat based would rarely make it through one growing season without extreme reduction in percolation speeds, indicating compaction, and medium shrinkage was always quite high - sometimes around 25%, indicating particulate breakdown. With bark soils I see good percolation/drainage/aeration, often for two years & in some cases (if I get lazy about repots) 3 years - and shrinkage seems to be about half of what I see in peat-based soils.

The second observation should answer the question about commercial uses. Sphagnum peat that comes in bales is highly compressed and nearly doubles in volume when screened. I know this because I screen it for use in hypertufa & when I build soils, I push it through a 1/4 inch screen to break up large chunks. Compressed peat by the cu. ft. is a little more expensive than pine bark, but once it's screened or broken up to incorporate in soils, it nearly doubles in volume, making it less expensive than bark by volume. Another consideration is it's largely free of soil pathogens & useful for new plant material. Initially, it retains its volume & aeration, making it a good choice for bedding plants & material that is kept in greenhouses for relatively short times. If you notice, most perennials & almost all shrubs & trees are grown in some mix of bark and/or (if the material will tolerate it) clay. Bark is used in this application because of its ability to retain its structure for a substantially longer time than peat.

I'm not altogether sure that I answered all your questions, but I think I got most of them.

I have a friend in a nearby city who is an experienced MG and long time container gardener. I gave her several cu. ft. of bark-based soil for use in her containers this spring. I'm going to send her a link to this thread & see if she would like to comment on anything in particular. She may or may not respond & I haven't discussed this thread with her other than to tell her I would send the invitation.

One last thing: Thank you for the kind words to Jane, Cheflara (still think that's a cool name), and Galileo who posted immediately above.

Al


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RE: Container soils and water in containers (long post)

Thanks for the invitation, Al, I'll gladly offer a couple of comments on this topic.

I've been making my own soil mix for several years, always focusing on the water retention part. Using Al's recipe for containers was an experiment I decided to try for two reasons. I compost, he doesn't and he offered to bring me some of his yard waste rather than put it on the curbside. I was disappointed (sorry, Al) to find the material mostly consisted of enormous root balls. Not ideal for my compost, I like to see a rapid breakdown, but in terms of plant health, these were the best root systems in containers that I have ever seen. Secondly, I listened to his soil talk, and although I always "knew" roots need air, I was finally convinced it was of vital importance.

This spring I used Al's soil mix for my containers, and made more of a similar nature. I must confess, I have never seen so much growth so early in the season. Moreover, my local gardening friend here and I bought the same plant at the same time (Fuchsia magellanica), both plants are growing in part shade. While her Fuchsia hasn't developed much since she planted it, mine is now full of buds and starting to bloom.

One great advantage of the fast draining soil is that I never need to worry about how much water my containers are getting. Overwatering has always been a problem on my shady deck. It'll be interesting to see how this experiment develops over the summer.


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RE: Container soils and water in containers (long post)

Just a question about my tomatoes in their containers. . .I am using Al's soil, and my plants are looking beautiful and plenty of fruit is on them all! The only question I have is that, because the plants are in the containers, the lower leaves are resting on the soil mix and they look sort of more textured and slightly yellow. The rest of the leaves on the way up the plant are fine. Could this be just from splashing them from the water jug when I water? If so is this ok or should I remove the bottom leaves completely?


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Jul 12, 05 at 14:25

If other leaves are deep green, it's probably natural senescence (aging) or a light issue if new growth is shading them. Leaves that are fungus affected (soil splashing on them) will almost always be mottled or show sharp contrast between necrotic & living tissue until entire leaf dies. If other leaves are light green, look to lack of N, it affects older leaves first, while deficiencies of sulfur, copper, and iron affect young leaves first. Magnesium shortage shows usually as inter-veinal yellowing.

If leaves are yellow, it indicates the plant has metabolized or translocated chlorophyll to other plant parts & the leaves would be of no benefit to the plant. You can remove them, or wait for the plant to shed them.

Al


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RE: Container soils and water in containers (long post)

Thanks again, Al, from your description it looks like these leaves aren't getting the sun or are just getting old.
Cheflara


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RE: Container soils and water in containers (long post)

Al, would you reveal the identity of the Micro nutrient powder you use and where in the world you find it? I have been searching the net, but am totally confused by all the sales pitches that I find. Composted manures I understand, but having trouble sorting through all the sales hype on the other stuff. Would I be wrong in assuming that the powdered form is mineral and would last longer? You can email me direct, if you like. Thanks!


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Thu, Jul 14, 05 at 18:26

Hi, Millie. What I use is Scott's Micromax micro-nutrient granules, and it is in mineral form. I've only seen it available in 50 lb bags. I buy from a nursery wholesale company who will only sell to you if you have a tax/business license & Fed ID # & set up a credit account. It's in the neighborhood of $80/bag + ship. You may be able to find another supplier with added info to your search from the link I'm providing.

There are other products that will deliver the minor elements efficiently. The seaweed emulsions and a product called Earth Juice are a good method of supplying them (see Home Harvest site). I'm not sure who makes it, but one of the major fertilizer manufacturers (Schultz, Scott's, Peter's ...) is now marketing a fertilizer that they say contains the minors. I think that would be just the ticket for lots of container growers.

I probably haven't helped much, unless you can use 50 lbs. of nutrient powder. ;o)

I didn't want it to seem like I bumped my own thread, so I'll add a tagline to this reply & take a minute to thank Britt (AlcesB), who responded to my invitation to comment a little way up the thread. I didn't know if she would, or what she would say, but I was pretty sure it would be favorable as she seems quite happy with her container planting's performance this year. She has a lovely wooded garden, chock full of wildflowers, and a shady deck area that she does some really neat things with in the way of container plantings. Thanks, Britt.

Take care.

Al

Here is a link that might be useful: Micromax


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RE: Container soils and water in containers (long post)

Al: Minor detail. In the formulation for the soil mix that you give at the beginning of this thread, there is the ratio of 3:1:1 for pine bark, peat, and perlite. This ratio is not maintained for the big and small batch recipes and there are differences in this ratio between the batches. I realize that these types of formulations don't require high degrees of precision. Please comment on these differences in the ratio. Thanks.
agmet_al


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Jul 20, 05 at 17:55

Oops! The actual mix I use is the big batch recipe, which is almost a 5:1:1 ratio of bark:peat:perlite as the primary ingredients. The small batch, of course is 6:1:1. The general recipe at the top should have been 5:1:1 instead of 3:1:1. You're right in that you only need to be in the neighborhood to get a good soil out of the ingredients. It still would work very well as a container soil, but might drain too quickly to suit some in the dry or hot areas. I hope any that might have used the 3:1:1 ratio as the basis for building a soil aren't hissing at me if they need stand over the containers with a hose more often than they prefer. ;o)

Sorry for the inconsistency.

Al


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RE: Container soils and water in containers (long post)

Just a note to say thank you on behalf of all of us for all that Al does to help us. He is so kind and patient and helpful that I know we are all extremely grateful.
We all thank you Al for being such a good sport and such a great help.
Betsy


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RE: Container soils and water in containers (long post)

  • Posted by farkee 10 B South Fl. (My Page) on
    Thu, Jul 21, 05 at 22:35

Thanks for the explanation as to why addtional drainage material in the bottom of a container can actually be a detriment.

Several years ago, I read that it was no longer considered good advice to add drainage material (pot shards, rocks, etc) to containers. I got all in a huff and thought THAT CAN'T BE---we have been told to add it in every book and article. I got two containers , two tomato plants and decided to experiment and PROVE them wrong--one had just potting mix, the other , layer of rocks and shards and then potting mix. I could not believe my eyes--the one without drainage aids DID SO MUCH BETTER. Probably 3 times the size in a very short time. Now after reading your post about the concept of PWT, I can finally understand the results of my experiment. Thanks for the info.


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RE: Container soils and water in containers (long post)

  • Posted by dawng 5 Canada (My Page) on
    Sat, Jul 30, 05 at 19:43

Al and others: thank you so much for this excellent discussion and info.

My question - have any of you Canadians found any pine bark fines? I can't see to find anything even remotely close. Would appreciate sources if you have any!

TIA!

Dawn G.
Ontario


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RE: Container soils and water in containers (long post)

Al, you have said that you normally repot most of your plants every 1 to 3 years.

Question? What do you do with spent your spent container soil? Does it go into garden beds? Compost piles? Can it be re-used in containers by adding some bark fines and perlite to freshen it up? If so, can the fine roots in the old soil simply be broken up or chopped up, or should the soil be set aside to let the roots break down before being re-used.

I'm curious because I've been container growing some veggies, and I'd like to get rid of some of the spent plants and get some new plants in for a fall crop.

Thanks, Scott


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Aug 9, 05 at 17:16

My thinking on reusing container soil: I usually don't do it. This year though, I planted pansies in 3 containers that still had the old root-mass fully intact. I just scuffed up the top of the soil & planted w/o any further ado They are growing strongly - even now, in all this horrendous heat. Qualifier: This is in a bark based soil that was highly aerated to begin with. I wouldn't have done it if it was a commercially prepared peat soil.

I think soils don't break down at an even rate. In other words, if the life of a soil is set at two years. It would probably be good for the first year, see 25% of its structural failure in the second year, and 75% of the collapse in the third year; and that would be loaded toward the end of the third year. The same is true of a soil whose useful life is only 1 year. If we mix used soil with "some fresh stuff" - say 50/50 - it rejuvenates it somewhat, but half of the soil is well on the way to total collapse.

I'm not being critical of reusing soil. Economics dictate it in many cases, and some folks can't stand to throw it on the compost pile as long as they think there's life in it. So be it. Adding pine bark and perlite to a used, peat based soil would definitely be preferential to adding more peat when viewed from a drainage/ aeration perspective, and pine bark based soils retain their structure at least twice as long as a peat based soil, possibly even three times as long - depending on watering habits (N supplementation frequency also has a large impact on organic soil breakdown rates).

BTW - All my old rootballs are spoken for. See post by AlcesB, about 10 replies upthread. ;o)

Al


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RE: Container soils and water in containers (long post)

Al,

In 2006 I will be doing more container gardening, after success with tomatoes last year, using your soil mix or something close to it. I wondered if you have ever planted a white egret flower (Habenaria radiata)in your soil mix, or used it in bonsai pots. I love the looks of this flower, but from some research I've been doing here and at other sites, it seems to be difficult to grow. It is considered a terrestrial orchid, and people say it is more of a bog plant. Some suggest alot of spaghnum moss and granite sand as the mix to
use. I have not found the plant itself for sale, but I can order bulbs to be shipped in March. If you have any advice in the matter, I'd appreciate it!

Cheflara


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Sun, Jan 29, 06 at 21:33

Hi, Cheflera. I was wondering if this thread would drop off the end before someone bumped it up again. ;o)

If you want to grow a "special" plant, why not build a special soil for it? I have not grown this plant, but from the little research I did before answering, I think it would grow almost perfectly in a mix of 2/3 Turface or 1/8" - 1/4" pumice to 1/3 pine bark. If I was growing it, I would only use 10% bark, but I'm used to watering every day. The mix I suggested would provide the drainage the plant needs & still hold reasonable amounts of water. If you find you need to water too often to suit you, you could add a wick & dangle it in a reservoir of water & it would self water. Your job is to keep it watered, provide the right light & figure out the ideal fertilizer program. Once you get it started, I'd be happy to help you pick out a perfect bonsai container for it.

I've used photos of these plants to illustrate that a soil with no organic component at all can produce perfectly healthy plants. The larger Portulacaria afra is about 7 years old from a cutting. The little guy in the acorn cap is about a year old in the photo. Both are growing in 100% Turface.





Al


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RE: Container soils and water in containers (long post)

Al,

Glad you could answer some of my questions regarding the egret flower, I think I'll take a "bold" step and order the bulbs in March and try to grow these plants. I will try the Turface/pine bark/fertilizer mix. I hope to keep up with watering, but I forgot about the wick idea, I may use that...

Thank you also for the pictures of your bonsai, they are quite beautiful. The acorn idea was really neat, I showed it to my daughter as I knew she would like it because she likes to "plant" different plants on driftwood and the tree in our yard. If I do get the egret plant going, I'd like to know what bonsai pot you think would complement it.
Cheflara


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substituting for sphagnum peat

I'm having trouble tracking down peat in the right form. It's either in expensive small bags or inexpensive giant cubes that don't fit in my car and would probably be too heavy for me to lift anyway. Can I use composted peat? I can get 30 or 40 lb bags of that which are manageable.

I'll be growing veggies in containers, rather than long term perennials if that makes any difference.
Flip


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Fri, Feb 3, 06 at 16:43

Sphagnum peat is usually readily available in quantities as small as 1 cu ft at places that sell plant material. You can also find it at a ridiculously high price (I just noticed you said this), sifted/screened, in smaller bags by the soils and soil components. If, by composted peat, you mean reed/sedge/Michigan peat, it has no place in container culture.

Al


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RE: Container soils and water in containers (long post)

I'm going to see if I can get a nursery to order me sphagnum peat in a manageable size. Everyone has the tiny bags and quite a few have the 3.8 cubic feet bags, but nothing in between. I went to one place today, tried to lift the giant cube just to see if I could, and felt like I should be building pyramids with it.

Re the composted peat: I don't recall if the bag listed the ingredients. All I remember for sure is "composted peat humus". I'll steer clear. Better safe than sorry!


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RE: Container soils and water in containers (long post)

fliptx,
The big box stores should be getting in their supplies of peat, pine bark, etc. very soon. They commonly have sphagnum peat in 2 cu. ft. bales, which should be more managable for you.

Jason


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RE: Container soils and water in containers (long post)

tapla,

I read your post several months ago, and came back today to search for the post. I was thrilled to see that there are new responses. If you have time, I have a question I would like to ask.
Last year I planted a couple of plants in some plastic planters and put in the front of my house. At the time, I didn't think they would live because it is pretty hot in this location. Soooo, I watered them every day, and used a lot of water. They always seemed dry, so I would water more. They did die, like I thought they would, but when I pulled them out of the pots, there was water puddled up in the bottom of the planters. Obviously, not well drained, and I overwatered.
Now for the question, there is not enough room in between our house and drive for both evergreens and flowers, so we are building cedar planters. Because we have a drip system in this area, I thought I could possibly not kill the flowers in them. (One can dream) I was interested in your mix since I clearly have a problem with overwatering. My question is: How much does climate play a role in drainage? My area is very hot, (Dallas area). I don't mind watering more often, but water prices here have gone up and there is a drought and talk of water rationing. I also don't want to keep killing plants due to poor soil drainage, and my inability to know when to quit watering. Any suggestions.
One more thing, I have spent hours reading the original post and all the responses. Thanks to you and everyone else who have spent their time giving such great information.


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Feb 7, 06 at 16:50

Thank you for the kind words, Maggie. ;o)

How much does climate play a role in drainage?

The real answer to the question is "none", climate doesn't affect drainage unless it gets so cold that water freezes, but I know you're looking for other information. Cultural conditions have a substantial impact on how quickly water is removed from the soil. Plants use more water and more water evaporates from containers when temperatures are hot and it's windy, so soils that hold more water can be easier to grow in under those conditions.

I'll explain. If you read through the thread, you are aware of the PWT that occurs at the bottom of containers in most, but particularly in heavy soils. This is probably never a good thing, but in some cases, it is necessary. You may want to grow in a very open and extremely fast draining soil that is exceptionally healthy for roots, but you may not be able to. People that work, or people that are not willing to water daily or even twice a day must use a soil that retains enough water to get plants from watering to watering. The problem with that, is the PWT. Roots begin to die very quickly when deprived of air, and the finest roots are first to succumb. When a portion of the container remains saturated for long periods, a portion of the roots die. When the plant uses enough water or enough water evaporates so that air returns to the roots, roots begin to regenerate. This is very taxing to the plant. If you water too frequently, and a portion of the container soil remains saturated indefinitely, that portion of the container becomes and remains uninhabitable to roots.

I mix soil a wheelbarrow at a time and return it to the bags the bark cam in to store, so I always have plenty on hand. I use it as a basic mix and add and subtract ingredients as I mix them for particular plants and containers. Container size and what it's made of (what the container is made of - I grow many plants in terra-cotta and wood boxes for the increased aeration, over and above the open soils I use) also impacts what I mix. I make a guess at what soil mix is appropriate for the plant material and will go a full day between waterings in the container I'm planting, in the hottest part of the summer, and with the plant material (in the container) all grown up. ;o)

You'll find that container soils that require more frequent waterings will almost always produce the most robust plants, as long as other cultural condition are equal. The reason is that they hold more air and have a lower PWT, making the entire container hospitable to colonization by roots.

If that didn't answer your questions, don't be afraid to ask again.

Good luck.

Al

I just thought of something else. In container culture, root temperatures play a significant role in water usage. Most root systems begin to shut down when actual root temperatures reach 90* F. or so. When this occurs, stomata close in an attempt to keep the plant turgid (prevent wilting), so soil temps also play a role in how quickly water is removed from soils.


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RE: Container soils and water in containers (long post)

Al,

Thank you so much for your quick response! Plus, it was exactly what I wanted to hear. I have no problem watering at least once a day, or twice when very hot because the planters we are building will have a drip system that runs off our sprinkler system. We can set the timer to just water those stations. Yeah.... no more soggy plants.

My DH has built a prototype planter out of cedar. We are not planning on lining it. I do want to paint them though due to a matching issue with the other wood out front. Do you see any major flaws with this plan so far?
Also, I was planning on using PW (proven winners) from a local nursery. I really like the combinations they have on their web site, mixing grasses, with flowers, and vines.

I do have one more question though.... Since these planters will be the focus of the front of our house, they need to look good year round. It could get very expensive buying enough plants for these things every season. I was thinking of planting some perennials in them, and when fall or winter comes, moving to a raised bed by the side of my house. Then transplanting back to the planters the following season. Also, in the winter, I wanted to put dwarf evergreens in them, again, using the side yard for a holding place during the summer. Will this work?

Thanks again for taking your valuable time to answer my novice questions. Denise


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Feb 7, 06 at 20:45

If you limit your perennial choices (the dwarf evergreens are perennials, too) ;o) to plants hardy to zone 6, you can save a step or two. You could also plant the evergreens in separate containers & move them to the planters (bury pot & all) when herbaceous plants fade. One thing to consider is the often short bloom time of perennials in comparison to annuals.

I think Gardengal is a zone 8 expert who's very good with plant material. I'll ask if she could help here with plant material suggestions. In meantime, perhaps others will offer suggestions as well.

Al


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RE: Container soils and water in containers (long post)

Again, Tapla, thanks for your quick response.

I didn't even realize perennials had a shorter bloom time. I usually just plant annuals in pots. So then I should be able to plant grasses and vines that last longer, and replace just the flowers between spring and summer. Grasses here are considered annuals anyway.

I never thought about keeping the evergreens in pots and burying them. That should work great! I really wanted during the Christmas season to plant something that looked like small Christmas trees that I could light up during the holidays. I would think this would work for them as well.

Again Al, you have given me such great information, and so many things to think about. I have mentioned to some of my real gardner friends your potting mix. Now they want the information Thanks so much. Denise


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Feb 8, 06 at 21:56

Denise - there are many, many perennial grasses you could grow in zone 8, and for "Christmas trees", consider Picea glauca albertiana 'conica' (dwarf Alberta spruce), or one of the upright junipers like J. scopulorum (foliage doesn't "bronze" in winter). If you will be summering the "Christmas trees" in anything but full sun, an upright yew might be appropriate. Taxus cuspidata capitata or Taxus "Hicksi" (Hicks Yew) might be a consideration.

Al


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RE: Container soils and water in containers (long post)

Al...could you elaborate on chloride damage?


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RE: Container soils and water in containers (long post)

Sorry for coming into this a bit late - after the deluge of the last few weeks, we have just jumped head first into spring and I got real busy real fast!!

Denise, acknowledging that your zone 8 climate is not the same as mine, I don't think that you should feel limited by what you can include in your new planters. Anything that grows in the ground here in my zone 8 can be expected to grow as easily in containers, given a few considerations. FWIW, most of my container gardens are year round, permanent plantings in that they winter over easily - the only exceptions may be some more semi-tropical items that will need winter protection.

Plant selection should be wide open in zone 8. Because your summers are obviously a lot hotter than mine, you might consider plants that will tolerate a lot of heat. In fact I'd consider that to be more of limiting factor than worrying about their hardiness in winter. Container soils can heat up significantly in summer and if soil temps approach 90F, you will notice significant damage to your plants despite frequent watering. I'd look first to plants that are xeric in nature - these tend to be better adapted to the heat as well as droughts. Some items to consider would be plants with Mediterranean origins - rosemary, lavenders, thymes, lots of salvias, euphorbias, most anything with gray, fuzzy foliage. You could look at hebes for smaller evergreen shrubs, a number of dwarf conifers (pines, junipers, etc). Sedums, stonecrops and other succulents should do well also. And I wouldn't hesitate to use grasses - many will thrive in these conditions and a good many are evergreen as well (fescues, blue oat grass, New Zealand sedges, even NZ flax or phormiums). In fact a lot of plants originating from the southern hemisphere would be excellent choices - Australia, New Zealand, Tasmania. These more permanent plants, which I tend to choose for foliage and year round durability, can be supplemented with more seasonal color from tough annuals or more showy perennials - you can simply plant these in their containers within your larger container and change them out as they fade or the season progresses.

Just re-read some of Al's previous comments and see he already mentioned the heat-root factor - great minds think alike :-)) I would also add that the larger the container, the less this becomes a serious issue, as there is more soil mass to insulate the roots.

Hope this helps and gives you some ideas on what to include in your new planters.


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Thu, Feb 9, 06 at 12:22

Breasley - probably, but give me some direction. Are you referring to plasmolysis (as in fertilizer burn), the effects of chlorides (ice melting compounds), chlorine in water, etc?

Al


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RE: Container soils and water in containers (long post)

Al... in your original post in the 4th paragraph, you said "yellow leaves are the first indicators of chloride damage" referencing wick watering.


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Thu, Feb 9, 06 at 20:37

As water is used by plants and as it evaporates, it leaves solutes (salts, specifically) in soils in increasing concentrations. Hi concentrations of soil salts can/will make water uptake by plants difficult or impossible. Water will not pass through cell membranes when the level of solutes in soil water is higher than in water bound within cell walls. In extreme cases, water is actually pulled from cells, even though roots might be awash in water. As water is pulled from cells, plasma is torn from cell walls and cells collapse, causing tissue death. This is termed "plasmolysis" and commonly called fertilizer burn, though it can also be caused by naturally occurring metal salts dissolved in the water you supply plants. It is much less likely to occur in well aerated soils that are watered from the top as water passing through the soil dissolves and washes accumulated solutes from the drain hole as it exits container.


Al


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RE: Container soils and water in containers (long post)

gardengal,

Thank you so much for all the wonderful suggestions. As this project has progressed, I have started worrying that planters this size, and 7 of them, it would cost a lot of money to maintain. So the ideas of evergreen grasses, and small conifers and replace the blooming flowers only, will not only look good, but save me a small fortune.
I love the tip to look for gray, fuzzy foliage. That's not the kind of thing they put on the tags at the nursery, and will be very helpful to steer me in the right direction.
I do plan on painting the planters. Originally, I loved the idea of having a black door, and painting the planters to match. Not to worry though, after reading these posts, I will be painting them beige. I do have a lot of trees on my property, although this area is on the west side of my house, it should be the best of both worlds, some shade to cool off the area, but enough sun to get flowers to bloom. I hope.

Thanks again for taking the time to give such a well thought out response. I have been going back and reading all the posts on this site. I have learned so much. Denise



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RE: Container soils and water in containers (long post)

Thanks Al... I'm starting to see things your way!


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RE: Container soils and water in containers (long post)

Hi Al,
You are such a great mentor to us I am going to reward you with more questions. These questions are mostly directed towards your Turface: turkey grit: pine bark (1:1:1) soil less tree mix that I plan to use for growing Ficus carica (edible fig) trees in large pots. 1) Im still not clear on the function of the turkey grit in this mix. Since the Turface is irregularly shaped and has lots of porosity and the grit has no pore space, why not just use 2/3 Turface and 1/3 pine bark and get the benefit of the greater surface area and lighter weight of Turface? 2) I have read a great number of your very insightful posts in various discussions and I still need clarification on the use of the terms pine bark, pine bark fines and composted pine bark. You mention that the composted bark is used in mixes for plants growing in it for 1 yr or less and uncomposted bark is used for longer term growth mixes. Do I understand correctly that bark fines are composted bark? 3) Is the pine bark (or fir bark) mentioned in your Turface, turkey grit, pine bark mix uncomposted? 4) Is there ever any toxicity problems when using uncomposted pine bark or has this only been attributed to cypress bark and cedar? 5) When using uncomposted bark you mentioned that it takes 2 times as much nitrogen to balance the nitrogen sequestered by microbial decomposition of part of the bark components. How much Osmocote (14/14/14) do you use per cu ft do you add to the mix containing uncomposted bark? 6) With the use of uncomposted pine bark, do you water with a fertilizer containing a higher proportion of nitrogen than is usually used in container gardening situations? 7) At what point in the life cycle of the soil do you no longer need to over compensate for the nitrogen? 8) What kind of wood do you use for making your grow boxes and do you treat it with anything? 9) How long do they usually last? 10) If I may ask, from what business in Chicago does your friend get you the fir bark? 11) Is there a practical way that I can measure total porosity and air porosity of potting mixes?

Thanks so much for your help Al!

Nathan


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Feb 15, 06 at 18:09

Hi, Nathan. I saw this before I left for work & thought "No way can I answer this in a few minutes".

The Turface is a great product for use in most soils, but few want to pay $8-9 for 50 lbs. One reason I use granite is, it's about half the price. The main reason is I like soils that require frequent watering. Soils that are watered daily or every other day, get a fresh charge of air each time you water - something that roots really appreciate. The granite provides about as much aeration and drainage as Turface, but holds insignificant amounts of water. I probably said that my basic soil for woody plants is 1:1:1 - bark:Turface:granite, but I regularly change that mix to suit individual plants. E.g., if I was potting an Acer, I would probably add an extra pint of Turface and a quart of bark to a gallon of that mix. For Juniperus, I would probably add a quart of granite to a gallon of mix. If you start adding larger quantities of Turface, you'll need to be sure fines are screened out. Even Turface that's too fine can turn Macro-pores to micro-pores, just like sand or compost.




I use terms "pine fines" and "partially composted pine bark" (at top) interchangeably. Pine bark (at left) might look like what's in the photo. This is about as large a product as I use - a little finer is better if you can get it. Either product will work well in container soils, so long as you recognize that the fines will tend to hold more water and less air, and the uncomposted product will require more frequent fertilization. I do usually use an uncomposted bark, fir (at right in photo) or pine in woody plant soils. I prefer the partially composted bark in soils for herbaceous plantings & veggies, but again - either will work.

I'm not trying to get anyone to grow in exactly what I use. I often say, "This is what I do" or "This is what has worked well for me." When I get specific questions like yours, others might get confused because I direct answers to an individual. I often point out disadvantages of using particular soils or components, but always expect that many will reject what I offer & continue about their business. I'm most interested in talking with those that are dissatisfied with their medium(s) or are already convinced that there is something better out there. ;o)

I have never encountered what I even considered might be toxicity problems from plant metabolism by-products in conifer bark, but my growing experience has only included pine, fir, and hemlock. I was recently on a question/answer panel for a garden group. and one of the other participants revealed info from a just-completed study that indicated that those plants grown under cypress mulch fared poorly in trials. Because of probable phytotoxicity issues, I would not consider using it in soils (in fact, I'm finished with using it as a mulch as well).

I'm guessing at using twice as much N in soils that have uncomposted bark vs. partially composted, but I'm close. I use a high N controlled release similar to Osmocote to get plants started, but don't rely on it. I think I am using a German brand of controlled release fertilizer I buy in 50 lb. bags. The formula is 19-5-8 with minors. While plants are active, I usually fertilize with a full strength solution of a balanced blend (20-20-20, e.g.) plus a full strength solution of 5-1-1 fish emulsion in the same water at same time. This varies by plant, but at least 75% of the woody stuff I'm growing get something like this. The flowery stuff gets a different program with more P. Can't answer the question about when soils stop needing extra N. Too many variables. You can get a rhythm in your fertilizer program by using the balanced blend as long as older leaves are nice & green. If you notice a lightening in older leaves, or a move to yellow, more N is required. After awhile, you'll know intuitively.



Here are some grow boxes I use for small trees for bonsai. They're made from scraps & crating lumber we get various things in at my business. They're untreated & last about 5 years.

I'll be seeing my friend at a bonsai meeting tomorrow night. I'll ask where he gets the fir bark & get back to you. On the bag, it says Vita-Bark - Fir bark for Orchids. It's packaged by Shasta Forest Products, Inc. in CA. Size is 1/8-1/4. I pay about 13.00 for 3 cu ft.

To measure soil porosities - I left this as an answer to a question on another forum:
"Your questions: Let's start with a dry media. It has two kinds of pores. It has the very tiny pores that are in the material itself. Some are microscopic and some are a little larger. We have to include the tiny spaces that are formed between soil particles in this category as well. These tiny pores are called micro-pores and hold water so tightly it is largely unaffected by gravity. Then, there are large pores, formed in the spaces between larger particles and particles that don't fit together well. These are macro-pores. The sum of these two types of pore space is the Total Porosity of the soil and it is measurable. Total soil porosity in container soils should never be less than 50% if plants are to grow to best potential - 75% is much better. If we wish to know the Air Porosity of the soil (how much air it holds), we can measure that as well. Air porosity in containers should be at least 25%, with 30 - 40% being better.

To measure porosity: It can be done by weight or volume - I'll use volume here. A) Close/cover drain hole and measure the volume of the container - record. B) Dry enough soil to fill container, + a little extra in oven until completely dry. Fill container to rim & lightly tap on counter or ground to settle. Refill to rim with soil) C) Fill soil-filled container with water, being sure all particles are completely saturated. It might take an hour or more when soil is completely dry. Measure & record how much water it took. This measurement is total pore volume. You should see water glistening at the top of soil. D) Remove the drain hole cover & catch all water that drains. Measure & record.

To calculate % of total porosity:
Divide total pore volume by container volume & multiply by 100.

To calculate total air porosity:
Divide aeration porosity by container volume & multiply by 100.

You can calculate the water holding porosity by subtracting aeration porosity from total porosity."

Phew! I hope that answered most of the questions?

Good growing.

Al


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RE: Container soils and water in containers (long post)

Al; thanks thanks thanks! I'm sorry I made you repeat so much of what you have said in the past but I just needed some clarification on a few of these issues. Thanks for sharing the easy to understand soil porosity method.

I can't wait to kick the peat habit and to try out some of your soil mixes and ideas. Well I just got my new pepper and tomato seeds in the mail and I better get my thermostats, heaters and fans checked out in my hot bed and all of this going for spring.

Happy growing to you too.

Nathan


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Feb 15, 06 at 20:52

Nathan - For the fir bark:

Oak Hill Gardens
37W550 Binnie Rd
West Dundee, IL 60118

(847) 428-8500

Al


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RE: Container soils and water in containers (long post)

Thanks Al.

I live only about 45 minutes from Oak Hill Gardens and I will be giving them a visit soon. I'm curious to work with the legendary fir bark.

Thanks again.

Nathan


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RE: Container soils and water in containers (long post)

Has anyone tried this product from ESPOMA
I just got two bags thinking it was similat to Profile, but is was slighlty larger and gray gravel like.

Al I mixed it with some Profile, Grit and small pine bark chips to make the conifer soil.
The bag says it does retain moisture - not sure how much.

Here is a link that might be useful: Espoma


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Sun, Feb 19, 06 at 21:28

Their (Espoma's) description could easily be describing Turface, so the products sound interchangeable. Espoma does up some beautiful packaging & puts fairly common stuff in them. Fired at 2000* is hot enough to insure it's a very stable product (won't turn to mush). I bet it's as good as or possibly better than Turface, and slightly larger is better in containers.

Al


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RE: Container soils and water in containers (long post)

It is larger in size that Turface -
It is also cheaper - 27 lbs for 9.99
The profile/turface is 40lbs for 29.99.

I combinned the Espoma with the turface and the grit - then the mini pine bark. This should work well for the conifers-


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Feb 20, 06 at 15:28

When I buy a pallet (40 bags), I get Turface delivered to my home or business for $7.97/ 50 lbs. By the 50 lb bag, it sells for about $8.50.

I'm going to buy a bag of the Espoma stuff, just to see what it looks like. For others reading this and who might wish to make their own houseplant soil, the Espoma product Plantman is describing, like Turface, should be absolutely great in your soils, including those for cacti/succulents.

Al


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RE: Container soils and water in containers (long post)

Hello, Al-

I have been busy trying to find the equivalent of chicken grit and Turface here in Europe, after the discussion of soil mixes in the maples forum - with, until now, limited results: the size of chicken grit here is smaller than BB size sand (about half), for instance, and is made of calcium carbonate. (Smaller poultry, I guess.)
There are however a number of products that are used for soil improvement of golf courses, parks, etc. Do you have any thoughts about synthetic media? I found expanded polystyrene flakes (called Styromull) and ureaformaldehyde foams (Hygromull)- the former improves drainage, the latter holds water. They are used in pots, as well.

Any thoughts about lava granules?

Finally, I remember you saying that the sharp edges of chicken grit improves root ramification. In other words, that this is not harmful but beneficial. Can you elaborate?

Thanks for all the generous info.


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RE: Container soils and water in containers (long post)

I have tried to read all the info on this thread and others and have confused myself greatly.

I know I shouldn't re use my old Pro Mix from last year. But may have to because of financial reasons. What can i add to it to make it more viable?

Also I just throw the mix in the container and do not create a drainage layer. Do I really need a drainage layer? I have read that some just put a layer of styrofoam peanuts on the bottom. Will this help?


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Mar 1, 06 at 17:46

Schusch - I'm sorry. I don't know how I could have missed your post. I thought the thread stagnant because it had "dropped down". It's likely that the soil improvers you can find will make good soil additives. Lava granules in 3-6 mm are very good. They will be more expensive than perlite, however. I'm not familiar the plastic foams, but as long as they are not phytotoxic, there is no reason they cannot be used as an amendment or component. I would decide based on the physical attributes.

I grow some plants in all synthetic media - no organic component at all. I even use chemical nutrients on them with very good results.

Fine rootage promotes finer branching - I do not know why, but bonsai practitioners are very aware of this reaction. Sharp and irregularly shaped soil particles promote root branching. First generation roots or the fine roots are the container work horses. They do all the important work and will even provide adequate anchorage for the relatively small plants we grow in pots. May I answer your question with a question? Does it make good sense to have your container full of fine, beautiful, useful, efficient rootage or with fat, ugly, lazy, useless roots. (I bet you hardly noticed how I tried to influence the answer). ;o) This is also why proper root pruning when repotting woody plants is key to vitality and longevity (another day).

Weebay - If you find you need to reuse your mix from last year, it's not a crisis. I don't think it's best, but lots of people argue with me & think it's fine. If you can find some fine pine bark, you can mix it 50/50 with your old soil. Add an appropriate amount of perlite, and you should come up with a very usable soil.

You do not need a drainage layer for good drainage. They do not promote drainage, only do they raise the level of saturated soil in containers. If you think your soil is holding more water than you wish, use a wick to drain the excess until your plant requires water at least every two days. Soils that remain saturated for too long kill roots and sap energy when roots rejuvenate. There is much mention of this throughout the thread.

Al


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RE: Container soils and water in containers (long post)

Thanks, Al-
I remember you mentioning that irregular but also sharp edges encourage finer rooting. It made sense, then I read about roots on carniverous plants that sharp edges could hurt the roots. Which is why I asked.

I recently discussed - via email - adequate soil mixes with two of the main maple growers here in Europe. When I told them I'd use bark piece sizes of 5-15mm (1/4 - 3/4 inch) they both encouraged even bigger sizes, one mentioning at least an inch. One of them mixes pine bark half with perlite and (unspecified) loam. Why the bigger size? When do the sizes get too big? I got the impression that they seem worried about keeping the mix cool in the summer, as much as good drainage.
They also discouraged peat, as you have, in containers with bottoms. In Europe peat is still used a lot in commercial soil mixes - one needs to find ecologically sound gardening brands to find non peat mixes. I talked to a representative of one of the more serious 'alternative' soilmix business in Germany (by serious I mean that trying to get away from peat is only starting, and sometimes the material used encourages disease and other problems, if of inferior quality). He recommended a special mix they do that has composted bark, wood chaff, cocofiber and cocopeat. This seems typical for 'alternative' mixes. Do you have any experience with those? The person (himself a grower, not only an employee) also mentioned having to add more nitrogen, since cocofiber/peat fixes it more. Any thoughts?

Thanks.


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Thu, Mar 2, 06 at 14:21

Larger soil particulates means larger soil pores which means superior aeration which means a very healthy rhizosphere which means sound rootage which means a vital plant is likely. Loam is a term that varies greatly from location to location To the Japanese, loam is volcanic rock that collects on volcano sides. It is often specified by color. I'm not sure what you call loam, here, it is equal parts of sand, silt, and clay - I consider it inappropriate in containers. I believe that in the UK, loam is compost or humus, so you can see it's difficult to judge its appropriateness in containers unless we know what we're talking about. Back to the particle size. Bigger is better, but bigger is also more work. As air porosity sneaks up past 40%, your soils will really require frequent watering - maybe twice or three times daily, depending on relationship between plant/container size. I grow in soils that are even more porous than I recommend here & try to build them so each plant requires water daily in the hottest part of summer.

You mentioned temperature - an important consideration in all container culture. High temperatures (over 90 - 95* F. or 32 - 35* C.) inhibit root metabolism and extreme temps kill roots. Neither are good, and the latter sets up conditions for rot organisms to multiply later after temperatures return to an appropriate range. Shade containers when possible & grow in white or light containers when you can. Partially burying your containers is a good strategy too. Roots will run into soil and any PWT will be eliminated by the wicking action of the soil. Pot in pot growing also can be utilized to remove the PWT.

I just don't like peat in volumes of more than 10-15% in containers for herbaceous material (flowers/foliage display plantings) and don't use it at all in my soils for woody plants. The plants just display much better vitality in the primarily bark mixes or in the case of woody plants, a mix of 1/3 bark & 2/3 inorganic parts. It's the added air in the bark mix. Sorry - I don't buy into the non-renewable resource peat thing.

About this: He recommended a special mix they do that has composted bark, wood chaff, cocofiber and cocopeat.
It's not as important to choose soil components, based on structural soundness, for plantings that are to last only a season as it is for plantings you'll have for two or more seasons between repots. I left this reply on the bonsai forum in answer to a question about using Coco shell mulch is a soil. It could easily have been offered as info on the soil(s) you're trying to develop:

"Those that grow in containers generally do not depend on the media for nutrients; rather, they look to the nutrient supplementation program they have in place. If your soil is supplying substantial amounts of nutrients, it is being attacked structurally by microbial activity - it is breaking down. The organic portion of bonsai soil components are carefully chosen to retain structure for the intended life of the planting. Conifer bark is a widely chosen and readily available soil component. It retains its structure for several reasons: It is highly lignified - decay organisms break down cellulose much more quickly than lignin, making bark a much better choice than sapwood chips e.g. Conifer bark is rich in suberin, which is a lipid that helps bark resist decay organisms by making it very difficult for them to cleave hydrocarbon chains. Suberin is often referred to as "natures water-proofing for trees", and its presence in greater abundance in conifer bark is also why we generally prefer conifer bark to that of deciduous genera.

To determine how valuable the CSM might be as a soil component, you might research the ratio of lignin:cellulose as compared to conifer bark. It almost certainly does not contain suberin in the amounts that conifer bark does. My guess is that it will not retain structure over the long term near as well as conifer bark."

There are many things that affect the amount of N needed in soils. Plant material, porosity, watering frequency, in what state of decomposition the soil particulates are in, and the resistance of the soil parts to biotic activity can all play a part. Generally speaking, soils made with fresh bark and those made with organic parts that contain a higher percentage of cellulose and/or a lower percentage of lignin than conifer bark will require more N in the nutrient supplementation program.

Al


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RE: Container soils and water in containers (long post)

Thanks again for the elaborations. I need study your response more.

I was indeed thinking about placing the 3 or 5 gallon pots in larger pots, both to shield them from the sun, as well as aesthetic reasons. I thought about filling in with pine bark. So you are saying if I place at least the lower part of the plastic pots in more soilmix that would help even if the holes are obstructed thereby. You are saying the water would exit anyway because of the wicking action of the surrounding soil? (May be I am asking a question that has been addressed elsewhere?)


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Thu, Mar 2, 06 at 20:04

It is probably referred to above, but the practice is called "pot-in-pot" or sometimes "pot-in-trench" growing. If you think about it, the extra pot with soil, or the trench makes the water in your container "think" or react as though the container is actually deeper. In the case of the PIP, the water in the PWT moves from your container down to occupy the bottom of the extended container, leaving your soil drained. In the case of the trench or just partially burying the pot, the water in the PWT would be wicked from the soil in your container to dissipate into the earth. In order for this effect to work, the capillary pull of the lower soil plus gravitational pull must be more than the capillary pull of the soil in your container. It should work for all but those soils that hold water so tightly we should not be trying to grow in them.

Al


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RE: Container soils and water in containers (long post)

Hey Al,

1)You mentioned adding liquid kelp preparations as a micronutrient source to your potting mixes, how do you feel about incorporating kelp meal as a long acting source of micronutrients? I'm reluctant to buy the regular big bag of Peter's STEM micronutient product (25 lb)and can't seem to find a smaller size anywhere.
2)Would it be useful to try to balance the increased need for nitrogen from the use of bark products by blending in feather meal? It is supposted to be a 4-5 month slow acting nitrogen source.

By the way, I'm not an organic fanatic. I only care about what works.

Thanks.
Nathan


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RE: Container soils and water in containers (long post)

Al, Is pine bark mulch different from fine pine bark? I wanted to make a small batch of soil according to ur soil recipe.

Nila


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Fri, Mar 17, 06 at 17:54

Hi, Nathan. I have to admit to being unfamiliar with the Peter's product you mentioned. I'd like to read up on it, so if you have a link or can direct me to where I can find something on it ... I looked & couldn't turn up anything interesting after about 10 minutes. Sorry.

I use fish and seaweed emulsions along with chemical fertilizers - I'm results oriented as well. I think that it's difficult to beat chemical fertilizers in containers for fast and effective results. I still use organic fertilizers, but they require biotic activity to break them down into elemental components the plant can use. The problem is: In containers, we cannot (maybe "should not" is a better phrase) depend on the boom/bust populations of micro-organisms being there when needed. Containers are generally much less hospitable to biota than mineral soils. Wide variance in temperature, moisture, and nutrient levels all impact soil organism populations. That said, I don't think I would depend on feather meal as a source of N in containers. Applications are easy, as is controlling concentrations with any one of a # of readily available fertilizer products.

Nila


The product at the top is partially composted pine fines. It is sold as mulch, soil conditioner, pine fines, aged pine bark, and under other names. I just found some in Troy (near Detroit) for a person that contacted me through GW (she doesn't know it yet, though - I still have to write her to let her know). Lots of places will have it in the spring. Pine bark mulch can be any size, but the bark on the left is probably approaching the upper limit (size) of what most of you would like to grow in. Need more help?

Al


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RE: Container soils and water in containers (long post)

Lowes has big bags of soil conditioner and/or landscapers mix. The brand is "Scotchmans". It pretty much looks like the partially composted pine bark in Al's pic. I didnt buy it because it is in big bags and I dont have room to store it on my balcony (plus I have to carry everything up 3 flights of stairs!). So you might want to check it out. That is the closest thing I have seen to the composted pine bark.

I potted all of my perrenial herbs in Al's mix last year. When I pulled one of them out of the pot recently, it had big strong roots all the way down to the bottom of the pot. I am sold on Als potting mix!

Lydia

BTW: A big "shout out" to Al! How ya doin? I havent been posting much but I check out this thread whenever it pops up. I made it through my first growing season and am about ready to start my spring planting!


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Fri, Mar 17, 06 at 20:16

I have been noticing some of your posts lately & have been wondering how you are faring. I thought that you'd forgotten me. ;o) Thanks for the vote of confidence, Lydia. You've come far in a year. Good job! Good Luck!

Al


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RE: Container soils and water in containers (long post)

Hello Al and everyone else too;

Al you know we cannot forget you. You are the godfather of container gardening and potting mixes. Whenever I am working on my container projects, I often ask myself "what would Al think of this or that?" I still haven't actually grown anything is your potting mixtures since I was a latecomer (2006) to this thread and Spring has not yet sprung here in South Wisconsin. I fact, just yesterday I finally found a local source of Gran-I-Grit. I am very curious to hear from everyone (such as katwomn59)who has contributed to this thread as to what kind of triumphs and setbacks they have had in using Al's potting mixtures.

Al, I made a false assumption on the Peter's Professonal S.T.E.M. (soluble trace element mix). I was on a citus container discussion thread http://forums.gardenweb.com/forums/load/citrus/msg071031588697.html
and they were using the Scott's-Sierra (Peter's) S.T.E.M.
http://www.scottsprohort.com/_documents/tech_sheets/H4078STEM.pdf
which is available in 1 lb quantities from First Ray's Orchids. However, in comparing the 2 trace mixtures, the Micromax that you use has 6% Calcium and 3% Magnesium whereas the S.T.E.M. does not contain any. This is probably due to the inclusion of dolomitic lime (calcium and magnesium carbonate)in the Micromax which would contribute Ca and Mg in about a 2:1 ratio. They do have all of the other trace elements in common but in different ratios. The S.T.E.M. is a water soluble product whereas I presume the Micromax is not due to it containing the dolomite.

This leads me full circle in my quest to find Miocromax in less than Al's industrial-sized packages. Has anyone found any souces of smaller bags of this product? Maybe this is an opportunity for some enterprizing person to start buying big bags of Micromax and to cut them down to 1 lb bags for sale to us little people.

Thank you Al.

Nathan


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Hardwood fines or pine bark

Al....

I have found "hardwood fines" at a local Lowes. They also have pine bark chips that appear to look like the product on the right side of your photo. Which would be best for a large container where the media is changed yearly? Most of the ready made container soils have composted forest products, peat and perlite in them ....do you recommend adding more pine bark to the mix or does this only apply to made-from-scratch media?


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RE: Container soils and water in containers (long post)

I found pine bark fines at Lowe's too, but the brand wasn't Scotchman's. I suspect the issue may be one of different "house brands" in different areas. Anyway, the fines I found here in Western WA were in a green-and-white bag, 2cuft for about $3, and displayed near the other bark mulches.

Kristin


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Sun, Mar 19, 06 at 10:45

Nathan - I don't want to have that kind of influence. ;o) Once you guys see the importance of air in container soils, you have the important stuff to build on. The rest of what I contribute is kind of unimportant individually, but might amount to something collectively. I've made some very special friends as a result of my time spent at GW, and I appreciate every one of them. Thanks for the nice comments.

I was unaware that the STEM product was available. It sounds intriguing. I will ask grower friends about their possible knowledge of it and report if anything turns up. Because it is soluble and can be applied frequently in small doses, it has potential to be even more effective than MM nutrients. We'll have to see. I wonder how well it stores? 25 lbs is not too much for me, but it would be for most hobby growers. I have a wholesaler in GR, MI that lists it for just under $50/25 lbs.

If you need a small qty of Micromax, I can put you onto a source - mail me.

ZZ - I would tend to stay away from the hardwood mulch, no matter how appealing it looks. It breaks down quickly & loses it's structure. Heat build-up (composting) can be an issue too.

Yes, you can usually improve a prepared/bagged soil by adding a good portion of pine bark to it. Those that reuse their soil from year to year would probably also benefit from excluding the compost, sand, and peat in favor of the bark as well.

Kristen - You already know that I think you'll do very well & be pleased with your efforts. I admire your enthusiasm, it's catching and a tremendous asset that will only help you convince your plants that they should do their best growing for you. You remind me very much of Lydia, who has posted to this thread many times. ;o)

Thread is winding down, but it's been great fun. A very dear friend pointed out how unusual it is to see a thread go so long and be free of any strife. You guys are great. All take care.

Al


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RE: Container soils and water in containers (long post)

Hello!...I am glad I ran across this thread because I am just getting prepared to put a soil mix of some kind into twenty large, deep plastic pots for outdoor container gardening(they are beautiful, Italian made relief patterned Faux Terra Cotta that I picked up very reasonably a couple years ago) I have a large amount of something called "Organic Compost" made by Soilprep at www. soilprep.com I bought it at my local Dollar treee Store for a buck a bag!(.5 Cubic Foot)...its made of "A medium/coarsely textured compost, rich in humus, and derived from various woods and forest products". I guess I am supposed to mix it 50/50 with regular topsoil, but my local soil is full of rocks and weeds and weed seeds. I am wondering how I can use this particular product in a potting mixture that will support the growth of many various types of flowers and plants? I want to grow annuals and perennials(some from seed, maybe a couple of container roses, some veggies and herbs, etc. Can I mix it with regular bagged potting soil instead of my rocky, weedy topsoil?(at what ratio?..and what else would I need to add?) I also found Blue Ribbon D.E. premium Cat Litter(made only of Diatomaceous Earth)..it says on the bag it can also be used as a "Soil Conditioner-mix with garden and potting soils to increase moisture retention".....would this be good or bad to add to my Compost/potting soil mix? I have Osmocote and can get lime if neccessary to improve my mixture. Any thoughts would be appreciated before I get started filling my TWENTY pots!....cost is an issue and because I have so many to fill, I am trying to do it smart, but without breaking the bank..thanks for any advise!...GardenLove


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Mar 20, 06 at 17:54

Hi GL - I went to the website & couldn't find out much about what your bagged material is made from. I suspect it is a mix of a wide variety of wood products that includes leaves, bark, and sapwood that has composted for a year or so. If you need to use this for economic reasons, there are probably ways to work with it to give you a soil you might be happy with. Is there a way you can send a photo of a handful of the mulch so I can get an idea of the texture - maybe even the content of it? I always mention that any sapwood and non-conifer tree bark is going to make some nutrient and possibly some structure problems over the course of a grow season, but I might be wrong.

You won't need the DE. It's much too fine for any soil use other than as a surface applied mechanically acting insecticide. Best to leave the garden/topsoil out of the mix, too. I'm thinking you might need some pine bark, some sphagnum peat, and some perlite (all pretty inexpensive components) to build a soil. You can e-mail me if you wish (if you've forgiven my errant e-mail). ;o) Or we can do it here.

The description of your home on your member page is impressive - sounds beautiful. Others might want to have a read. Good luck.

Al


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RE: Container soils and water in containers (long post)

Al, I wasn't able to find pine bark similar to the one u have showed in the photo, the pine bark mini nuggets looked like the left one in ur picture, so what else can i use? can i buy these and use it for next yr? I will look out for it in other nurseries and garden centers.
Nila


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RE: Container soils and water in containers (long post)

Hi Al, and everyone here...

I'm fairly new to this forum and am enjoying learning more in preparation for this spring and summer.

I plan on making a big batch of your soil mix this month (my son is a Turf Grass Agronomy major, so Turface should be easy to come by :). I wondered if there is anything in particular I should do to help with moisture-retention? I am in Memphis (z7), and the main problem I have in the summer is frequent/quick drying-out of my containers.

Thanks so much for sharing your expertise!

~Andrea


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RE: Container soils and water in containers (long post)

  • Posted by anney Georgia 8 (My Page) on
    Mon, Mar 20, 06 at 19:23

southernheart

Put water gels in your planting mix if you want to water less often, and try the soiless mix recipes that have been posted in this thread. Just google "plant water gels" and you'll see many descriptions and brand names of them.


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RE: Container soils and water in containers (long post)

No Al of course I haven't forgotten about you! For various reasons, I have been spending less time on the internet. I still check out the various threads. But after getting through my first growing season, I am more relaxed. I have learned a lot and I dont freak out over every little thing and send panicy emails or posts like I used to LOL! I remember you telling me not to stress so much and gardening is pretty much trial and error. And I have seen for myself that you were right!

It is finally last frost in my zone, and I am poised to start my spring planting. This year I am planting all my perennial herbs in cocopeat and coconut husk chips (CHC). Everthing did really well in the pine bark mix but as I mentioned before, I had a hard time getting the pine bark in manageable quanities. Plus most of my herbs like dry conditions so I had a problem with the rewetting issue. So I have switched to CHC (but still using your recipe!). Everything was growing just fine, but I got a spider mite infestation and trashed most of my plants towards the end of summer. I replaced the thyme and sage and potted them in the CHC and cocopeat. And they seem to be doing great. It is more expensive and not easy to find in some places, but I got the cocopeat at a hydroponics store (and was actually cheaper than regualar peat). The CHC I got from a local orchid supplier. I think it will work well for me in this hot climate. The CHC drains really well and stays pretty loose. There is no problem with rewetting and it is supposed to hold up even longer than pine bark.

It may not be practical in large quantities. It is not cheap and probably not readily available everywhere. But for people who dont need large quantities, have a tendency to overwater (like me!) and are growing perrenials that need both dry conditions and good drainage and aeration, I think it is worth trying. The biggest hassle is the washing and rinsing necessary to get rid of the salt.

I know you are able to get pine bark, etc in cheaply and in bulk, and you know it's properties, but if you ever decide to experiment with CHC and cocopeat, I would love to see what you think!

Lydia


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RE: Container soils and water in containers (long post)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Mar 20, 06 at 21:48

Wow - I see this thread has shifted to high gear. The soil I make is not a guarantee that all will go perfectly. It is just a blend that has shown to reliable retain its structure for a full growing season and in most cases two. The other soils I mention incidentally that contain the Turface, Haydite, pumice, crushed granite, etc., are soils I use for woody things that may go extended times between repotting. In every case, it is the soil aeration and drainage that are my first consideration. There are too many physiological issues to contend with (root-rot aside) for me to consider growing in a mix that doesn't drain or hold air. THAT is the most important thing anyone can take from this looong thread. Lack of air in the roots is most often responsible for things even as seemingly removed as insect infestation and fungal attack - lowered defenses (energy) due to compromised vitality.

It's not necessary to use the mix I do to have good vitality in plants. I always hope you will find a way to try the soils I use because it they make your job easier and minimize mistakes, but all are not willing to go through so much trouble to find the ingredients. Keep your eyes peeled for the bark, it's worth looking for and using, but don't worry so much if you can't find it.

There are lots of good tips upthread from others, too. I like to water frequently, so I have no use for the polymer crystals, but I know they work to extend watering intervals - that from Anney and others (I'm sure you saw that, Andrea? Welcome to the forum, too btw). Lydia is a year into her gardening adventure and looking for ways to improve on what she was using, tailoring soil(s) for specific needs. Cheers on you, Lydia - and I will try the chc's on some plants this year.

Good growing.

Al


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RE: Container soils and water in containers (long post)

Thanks so much to both anney and Al for the advice...I will definitely use those, also!

~Andrea


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RE: Container soils and water in containers (long post)

Hi all,
For those who may doubt Al's wisdom, on drainage, aeration and PWTs (you haven't forgotten PWTs from last year already have you?), I performed an experiment and was amazed by what I saw. I filled a large styrofoam cup with 1000 mL (about 1 quart)of Turface MVP which ends up being 6.25 inches deep in the cup. I saturated the Turface to it's top with water and allowed it to sit a day and then added more water to top it off again. I then poked several small holes in the bottom of the cup and allowed the water to run out until no more came out of the holes. This only took about 15 minutes since Turface is very fast draining. At this point 265 ml of water ran from the holes in the cup. I then used a pair of very pointed forceps to shove a rayon wick up into the Turface through the bottom of the cup and immediately a small stream of water ran down the wick and an additional 80 mL drained from the wick. Most of this within the first hour afterwards. This shows that Turface MVP has an air space of about 35% just as the manufacturer claims. The interesting thing though is that I calculate that the added 80 mL of water if left standing in the pot would leave the bottom 1.8 inches of the potting medium totally saturated. Most roots could not grow or survive long in this saturated zone as it would be a very unhealthy low-oxygen place for them. Turface is a highly porous and fast-draining medium. Although I haven't tried it yet I'm sure that the same experiment performed with a peat based potting media would have much worse results. With the PWT and the saturation zone being much higher in a pot filled with this much finer medium. This may just be a re-hash of what many of you already know but it is fascinating to see the physics of it operating right before your eyes.

Good luck everyone.

Nathan


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RE: Container soils and water in containers (long post)

Al and Nathan, I hope that you don't mind my sharing a humorous story about Turface, that really highlights your points and underscores how respected a product Turface is in the industry.

My son is a Turf Grass Agronomy major at a large Southern university, and did an internship last spring/summer at one of the major league baseball spring training facilities in Florida. Turface is used for excess water on the fields that occurs during rainstorms, especially those "popcorn" showers (downpours) that occur frequently in Florida. It has helped prevent many a game "rainout" due to its effectiveness. It takes many bags of Turface to do this (for one game), which can become a bit pricey---so it's a protected commodity in the baseball industry.

During one sudden torrential downpour, the Grounds Crew quickly pulled the tarp over the infield, and then took cover in the visiting team's dugout to wait out the storm. The Turface bags were kept to the side in the visiting dugout, near where the Grounds workers were standing. The visiting team's pitcher had a bad inning just prior to the rainstorm, and came into the dugout kicking and throwing things, as they sometimes do. As he looked for things to use to vent his frustration, he eyed the bags of Turface to the side, and the Grounds workers caught his glance, and could tell that he was tempted to kick them, also. They immediately, in *unison*, said "don't even think about it!". Throw your glove, knock over some bats, kick the bubblegum containers over, but don't mess with the Turface...unless you want to take on the Grounds Crew... :)


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RE: Container soils and water in containers (long post)

What a fantastic thread. Iowa Jade from the Rose forum drew my attention to it.

I'm about to pot up a huge container and will attempt to follow the advice. Some questions if I may.

I am generally happy to water every day but for times of going on holiday etc and having to leave my poor plants in the care of an uncaring non gardener I will also be continuing the use of water retaining gel crystals unless anyone thinks that's a definite no no. Having just done a recce of the local homebase (I guess that's like the UK version of Home Depot). I think the mini bark chips they have are about 1/2" is that ok size wise? I have some vermiculite in the back of a cupboard at home which has been sitting there for years would it be possible to use some of that along with perlite (as a part perlite replacement) to use it up or would that be a bad idea? I couldn't find any plain peat at my store would all purpose compost be ok or would that be very bad? I have previously believed (and I'm not certain entirely where my beliefs came from) that using a part compost/peat based product combined with a loam based product and manure was a good idea. Some stuff planted that way (thirds of each) seems to be just fine but I'm always on the lookout for improvements.

I can't wait to try the wicking. I've never been particularly comfortable with the idea of drainage matter at the bottom of pots. As I grow space hungry clematis as well as roses I've always thought they would probably prefer more soil to grow in.

Thanks for all the input everyone. It has been very illuminating.


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dwarf citrus in pots

Hi Al,a lot of interesting information here.
I have been trying to grow dwarf citrus for ages and keep on
drowning them in variuos potting mixes.They tend to drop their
leaves and twig die back and then snuff it.I live in Auckland
new Zealand and we get a lot of rain through winter.I have
tried chc/peat at 4 to 1.I have tried chc/coir and 4 to 1
and they have still remained too damp.I know now as well as
staying too wet they are not getting enough air in their
roots. I was thinking of doing one of two things
1.potting in pure 1/2 inch chc chips in a tallish pot,i am
concerned about shock from transplanting from a tight medium
from the contaner mix.
2.Transplanting into a coarse free draining orchid mix.
It doenst go over 26 c here in summer and the mix must drain well.Any advice would be much appreciated,cheers


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