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Container soils and water in containers (cont.)

Posted by jdwhitaker 7TEX (My Page) on
Sat, Mar 25, 06 at 21:39

Al's original post has reached the maximum of 150 replies, and I think this discussion should continue. I'll start the new thread with a reprint of Al's (tapla's) treatise on container soils and water, and end with a link to the original thread...


CONTAINER SOILS AND WATER IN CONTAINERS
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

Here is a link that might be useful: Container soil discussion 1


Follow-Up Postings:

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RE: Container soils and water in containers (cont.)

JD...thanks for doing this for us. This thread is an amazing warehouse of knowledge, isn't it? Good questions and an incredible exchange of information. Al...thanks from all of us!

Dorie


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Sun, Mar 26, 06 at 13:25

Scheesch - thanks you guys. I don't know what to say. The truth is, as the thread wound down, I was hoping there would be enough interest for someone to want it to continue, but I didn't think I should be presumptuous enough to repost it myself. The e-mail that this thread has generated keeps me pretty busy, but I really enjoy it. I have "met" some very interesting and good people - some participants & some who lurk & only wrote off forum. Many have written to ask if it would continue. I said I wouldn't repost, but feel free if you wish.

Thank you JD, for the kind words (e-mail) and for posting it again. I mentioned this before, but I think it is so nice to have a thread so long that has some disagreement, but no rancor. I guess it goes toward the proof that you guys on the container gardening forum are the best. ;o)

And thank you, Dorie. As you know, your encouragement & friendship means a great deal to me. I have great respect for your knowledge and your willingness to share. You are, without doubt, one of this forum site's greatest assets.

Al


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RE: Container soils and water in containers (cont.)

Can this thread be listed in the FAQ's for this forum? I think a place of permanance would be in order. I learned a great deal from reading it. Thanks for all the information!


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RE: Container soils and water in containers (cont.)

Geez--Ok, I was up til midnight reading the original thread and then printed off the whole thing--over 90 pages, and then went through 2 pots of coffee this morning re-reading it and taking copious notes. I'M ADDICTED. I just kept saying-"-Wow--this Al is amazing." I think my husband thought I was having an on line affair til he looked at my 90 pages and laughed. "only YOU would find THAT stuff so exciting!"
I'm glad I'm not the only one! Thanks, Al!
Debbb, Oregon


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Sun, Mar 26, 06 at 20:44

Ok, that's enough thanks you guys. Let's get back to garden talk. You're embarrassing me. ;o)

Debbb, I answered your e-mail, but I think your husband returned it - unopened. Seriously though, it wouldn't go through. That's been happening alot lately through GW. Wonder what's up with that? Send it again with your address & I'll resend the reply - OK? 90 pages, huh? - he's probably right. ;o)

Al


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RE: Container soils and water in containers (cont.)

The bark stuff I have found is called soil conditioner and it's very fine (not really many lumps at all is this ok to use?


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RE: Container soils and water in containers (cont.)

Hi Esthomizzy,

If you go back to the original posting for this thread, you will see a picture posted by Al of various barks. If your bark product looks like one of those you may have the right stuff. I think Al frowns on products that are too fine such as certain peats and composts since they clog up the pore space, hold too much water, drain too slowly, impede air movement and break down too rapidly. I hope I'm summarizing Al correctly.


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Mar 28, 06 at 16:46

Some of you guys are attaching way too much importance to "what Al thinks" - seriously. I just try to put info here for you to use or reject as you see fit, according to how things work for you. Hopefully, some of what I write will help put words to what problems you've already seen in containers and help you to avoid repeats or even new potential issues. I suppose I pretty freely express opinions here, but I'll try hard not to frown on certain practices. ;o)

I think I would decide on what Esthomizzy's found, based on whether it is primarily conifer bark or if it's "hardwood forest products", which might be anything. I would be happy to have found it if the former, and would maybe use it as garden mulch if the latter.

Al


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RE: Container soils and water in containers (cont.)

The stuff I have looks like the top one in the soil picture so I hope that's ok because it's too late to abort now. I'm just about to park the last plant in it :) 200litres or so - so far and my back is killing but it will all be worth it I'm sure :) just stopped for a tea break.

I'll post a picture of my hard work tommorrow if I can find my camera.


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RE: Container soils and water in containers (cont.)

I'm usually found yakking over in the Fig Forum (hi, Al!), but this thread is just what I need for asking a specific about the fired-clay soil conditioners that go by brandnames like Turface MVP, Schulz Clay Soil Conditioner, etc.

I did research in my area (Indy metro) this morning locating a source for the Turface and did find one, but it's clear out on the northwest side (going to mean nearly 1 1/2 hours round-trip for me). While doing a 'Net search on Turface, I came on a thread in bonsaiTALK forum which discussed it and alternative (cheaper) products, including something called OilDri, found at Sam's Club and Walmart (so the poster said). Sounded very cheap (about $4-$5 for a large bag at Sam's, not quite as inexpensive at Walmart, maybe same price for ~10 lbs.) Color is yucky gray, but ability to act as a fired-clay (and permanent) soil conditioner is equivalent to Turface at about half the price. Also mentioned are equivalents in cat litter (seriously!) called Biosorb or similar, found in bulk at pet supply stores, and of a decent particle size.

Can anyone here comment on whether they've used these to add to their container soil, and if there's any negative to it, other than maybe being unattractive color-wise in a potting mix? If I can find similar things locally, it'd save time and money rather than hiking a considerable distance to the only Turface distributor in town that I could locate (though they said in a few months time they are moving to within three miles of my house!). And if there's no appreciable difference between this and something like the Schulz product (allegedly even more pricey for the 50# bags), then maybe OilDri or the high-level cat litter is the way to go. Comments appreciated, as I have a ton of fig plants to repot before the weekend, they are breaking dormancy fast!

(p.s. I think Al's original post should *definitely* be in an FAQ spot in the GW forums - he is a blessing of information, and a dear friend :o))

Sherry


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Mar 29, 06 at 17:59

Esthomizzy - we'll look forward to the pics.

Hi Sherry. So nice to see you here! ;o)

I don't use color as a determining factor in choices of soil components, even in bonsai soils. If I need a plant to look pretty, I can top-dress while it's in the spotlight. The potential problem with oil-dri, and cat litter is that it is used as a very temporary product. I know of cases where the product was fired at temps too low for the product to be durable (retain structure) in soils. In these cases, it reverted to the clay it was made from - not a good thing. You'll see this kind of "it's good/it's bad" banter on all the bonsai forums.

You may be able to find suitable substitutes like Haydite or pumice (small lava stone) more readily? Let me know if I can help more here - please. If I lived closer, you'd have what you need readily available. ;o)

YBIC&PA


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RE: Container soils and water in containers (cont.)

I'm so glad that I found this (and the parent) thread in time for spring! I live in an apartment and only have a few houseplants so far, but I'm looking to expand my gardening experience starting this season. Understanding root-soil-water interactions in containers has not only been fascinating, it has also given me a degree of confidence as I proceed with my fledgling explorations.

I do have a question about the use of a wick in containers. As I understood it, the container either needs to be elevated from the surface, double-potted, or placed on unsaturated absorbent ground/soil for the wick to work effectively, right? Here are my questions:

-- Most of my pots are going to be on a concrete patio. What are some of the common methods and/or devices that can be used to elevate them off the surface enough such that the wick can trail down?

-- With the advent of warmer weather, overheating is soon going to be a problem with my containers. Most of my pots are terracotta. If I am to double-pot them, what material(s) should the outer pots be made of, ideally? Also, what should I put in the space between the two pots? As an alternative, will wrapping the pots in foil help lower the temperatures, or will the benefits be offset by the foil blocking the evaporative action of terracotta? Can I wrap them in something that can be moistened (rope/thick cloth etc.) at peak heat or will that lead to adverse effect on aeration?

I realize I've asked a lot of questions here. Being a newbie seems to be the culprit :-) However, I'd appreciate any guidance I can get!

Thanks,
Anchita


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RE: Container soils and water in containers (cont.)

Hi Sherry,

I also went through a big quest to find Turface MVP in my area (Chicago/Milwaukee). I finally got in touch with a Profile Products (Turface' parent company)salesperson for the area. He was very helpful and emailed me a list of distributors in my area. I'm thinking there may be more in your area than you know about. You might try calling Profile at 800-207-6457 and have them put you in touch with their sales guy. Sorry I can't remember his name or his number.

As far as the Turface price goes, if you can find it, around here it sells for about $10.00 per 50 lb (about 1.3 cu ft) when you buy it one bag at a time as I do. If you need a smaller amount (20 lb) and want to pay, any well-stocked water gardening supplier and even some Walmarts carry a Schultz product (made by Profile Products) sold for growing aquatic plants that is the same thing as Turface but it costs about 5 times more than Turface MVP. If I come across the sales person's contact info I'll send it to you.

Good luck.

Nathan


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Fri, Mar 31, 06 at 18:02

Anchita - you sure you're a beginner? Your questions show that you are paying close attention or know more than you let on. I'm impressed. ;o)

You have how wicking works understood correctly.

Anything that elevates them a few inches will work. 2x4, 4x4, bricks/blocks/pot feet, etc

You also understand the science of keeping container soils cool. The foil will interfere with evaporation, but it will reduce relative heat gain by about 75%, so it would be a good, though possibly unsightly, thing. Wrapping them in cloth or rope to be moistened would work, as will shading the pots. Double potting is good too, and pea stone is a good fill material. If possible, during hottest times, water at mid-day.

Al


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RE: Container soils and water in containers (cont.)

Hi Al,

Thank you for your response. Exactly what I needed to know :-)

Finding gardenweb has been such a blessing for me. And most of what I've "learnt" about container gardening, especially about soil-water dynamics, has been from your posts (and the ensuing questions/responses/threads.) I've been lurking here for a month or so, and have been doing some intensive reading... It has been fascinating, and hopefully my gardening will benefit from it.

This weekend, I'm off to find the ingredients for the soil mixture you've suggested for containers, and then it is partial root pruning (for my houseplants) and re-potting.. And, well, some new plants :-) It is so much more exciting when you know not only the how's but also part of the the why's!

Thanks again,
Anchita


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RE: Container soils and water in containers (cont.)

Hi everyone,
Al, I was reading about growing media on a bonsai (Bonsai Nurseryman)website
http://bonsainurseryman.typepad.com/bonsainurseryman/2006/02/science_and_soi.html
and the interesting opinions and observations of Brent Walston. Brent has observed that in using the lighter and more aerated mixes results in larger heavier roots than when finer less aerated mixes are used which he sees as resulting in finer less robust roots. I think a lot of his experience is with maples which is right up your alley. Is there anything in brents views that you disagree with or would comment on and have you observed similar phenomena. It is an interesting article that you, with your voluminous knowledge of the field, may already be familiar with.

Nathan

Here is a link that might be useful: BonsaiNurseryMan: Science and soils


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Sat, Apr 1, 06 at 19:40

I have been a customer of Brent's for a good number of years & have read everything he has published on his site. I have learned much there and respect his knowledge and opinions. I also know him through conversations on other forums. I saw nothing in the entire article I disagree with that's worth mentioning. Even if I did, I would be disinclined to question Brent's methods as he makes a living growing plants in containers, and I am a hobbyist. ;o)

PS - Brent grows an amazing assortment of plant material in containers, maples being only a tiny %. You will do yourself a great service if you pay close heed to what he puts forth.

Al


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RE: Container soils and water in containers (cont.)

  • Posted by ralnac MTprairie z4/5 (My Page) on
    Sun, Apr 2, 06 at 21:30

I keep wondering whether my idea to grow in a container with no drainage will work, and if you all have some suggestions for a soil mix for a boggy type plant.

I have three beautiful old steel milk cans, which for obvious reasons I don't wish to drill holes in. However, a one-gallon plastic pot like perennials come in fits handily into the top.

I was thinking maybe I could grow something like elephant ears that, from what I have gathered, would be happy in a boggy/wet situation. If I set a pot in the top of the can, I must fill the bottom of the can with something so it won't topple over in the wind, i.e. river rocks. I was thinking maybe I would run a wick from the container down into the rocks and fill the bottom with water as a reservoir and have a self-waterer. My concern with the above scenario is that a big plant like elephant ears will still topple over if there's only a gallon sized pot setting in the top of the milk can. Would be probably be better to plant in more soil, directly in the can. However, then I have a drainage issue. These plants do like it on the wet side, from what I can gather.

Any thoughts or ideas how I can use my 3 milk cans and what soil would do?


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Apr 3, 06 at 16:52

I don't feel comfortable enough to offer much advise. There is a fine line to maintain in bog containers between aerobic & anaerobic conditions. If no one else offers aid, perhaps you might ask on the bog garden forum.

Hint: There are several plants referred to by the commom name "elephant ears". For best advice, nail down plant you're asking about by offering its binomial name.

Al


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RE: Container soils and water in containers (cont.)

Dropping back in here quickly (I've had my hands literally full with fig repotting), thank-you's to Al and Nathan on replies about Turface and other similiar soil amendments - does anyone know relative weight/volume of something like Turface (when wet) compared with pumice (lava stone) or Haydite, in a container? I'd rather have some of the moisture and nutrient retention of those components, compared with Perlite, but need the containers to weigh less where possible when creating custom-blend potting mixes, just because the pots larger than 15" diameter can get heavy to lug around. Definitely want to hear of sources local to me in the north-eastern Indy metro area (I'm in Noblesville, north of the city), for any distributor carrying these within a short-range drive.

Really liked the link to Brent Walston's article, btw. I was confused to read, however, that he states being reluctant to use much vermiculite in his mixes, because of it breaking down into something more like clay over time - I thought it was a heat-exploded mineral-type soil amendment and stayed fairly inert? anyone know?

Anchita, I'm glad you brought up the foil-wrap question for your pots, I was thinking to do the same thing and maybe even use some on top of the soil to reflect light back up into the figs and baffle too much rain soaking in (make a perforated moisture barrier), though it would look a little space-age-y and the neighbors might furrow a few brows :). Does anyone know if contact paper sticks to plastic containers?! I thought of that as another means to reflect heat away, but it might not be economical or any more attractive. How cheap is burlap, and would that work as a general "drape" for being able to keep the pots wetted down and cooler? Thanks for everyone's great questions and input, I definitely keep learning as I go along here, the wealth of knowledge is much appreciated.

Sherry


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RE: Container soils and water in containers (cont.)

Regarding the pot-cooling issue, I'm thinking of another way of double-potting, which would probably be more like "basketing." I found some really cheap plastic baskets that should fit the outside of most of my pots, with some space to spare. I was wondering if filling this space with mulch would work? I'll try to post a picture of this arrangement later. Any thoughts/suggestions about this would be much appreciated.


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Apr 4, 06 at 18:17

Anchita - that sounds like a really GOOD idea. If the baskets are woven to allow air through, and ESPECIALLY if they are white or light colored ... You really have something there. Filling with mulch or gravel will allow evaporative cooling to help cool pots - PLUS the shading and reduced solar gain from the light color will be very helpful. When you get this set up, you should start a new thread with a catchy lead-in to attract more attention. Cheers on you & your resourcefulness!

Hi Sherry. ;o) I wanted to make some calls today, but got involved in something this afternoon. The Perlite is going to be about 1/10 of the weight of other water/air holding mineral components. Turface and Haydite will be close in weight:volume ratio & pumice slightly lighter volume:volume compared with the others. I agree with Brent on the vermiculite thing. It breaks down and compacts. I've used it to start different seeds in and have witnessed it lose 75% or more of its loft after a few waterings.

From talking to you on other forums & in e-mail, I think you could forgo the use of mineral components other than perlite on all the containers you'll partially bury & still be ok for 3 years or so because of the wicking effect of the soil. Even I would do that for containers destined to go in the ground as it reduces drainage to a non-issue, practically speaking.

Al


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RE: Container soils and water in containers (cont.)

Finally finished (well a week ago but I couldn't find my camera for a bit as I'd cleverly hidden it down the back of the sofa in case we get burgled).

Hooray it's only taken a year to get this sorted (I needed building box help from my significant other and he's very particular about things to the extent of things taking a very long time but being built to his exacting standards). I'm looking forward to sitting on my deckchair and looking at my flowers this summer.

Image hosting by Photobucket


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RE: Container soils and water in containers (cont.)

Al,
You are a great source of info on soil mixes and water wicking, and I very much appreciate your input.

However, I think you have overlooked a critical factor in your conclusion that a drainage layer is useless for drainage.

You mention the PWT, but every layer of anything in a container will have a PWT, even the rock layer for drainage. It will effectively be zero. The overall PWT for a container is the combined PWT of the components. In this way, the rock layer at the bottom DOES lower the PWT of the soil mix above it, because it is a combined effect.
For example, if you mixed the rocks into the mix the PWT would be affected, and the fact that the layers are separate makes no difference.
Try this--make two containers, one with a drainage layer and one without, with the soil mix the same in both, and a hole in the bottom of each. Put your wick hole at the bottom of the container along the side at the same place in each and see which drains more liquid. The one with the drainage layer removes more water. (Make sure that the wick is positioned at the bottom side of the pot, inside the layer of drainage rock.)

What you are assuming about the PWT being the same with or without the DL (drainage layer) is that the soil is against a solid barrier, such as the bottom of the pot, when in actual fact it is against the rock layer which is porous.

Having said all this, I think your wicking system is brilliant, and I in no way mean to insult you. I am an engineer and this sort of thing is just what I do!
AJ


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, May 3, 06 at 20:33

Hello, AJ. I don't make the assumption that soil above a drainage layer is against a solid barrier. Placing a water retentive soil atop a drainage layer causes water to "perch" above the drainage layer. I also cannot agree that mixing the drainage layer into the soil must appreciably affect the ht of the PWT.

Experiments: A) Imagine starting with a soil that retains a 6 inch PWT. Now, layer 6 inches of it atop a 3 inch drainage layer of marbles or ball bearings and saturate the container. The lower part of the container will drain freely, while the 6 inches of soil at the top of the container will remain almost entirely saturated. Not enough water will drain from it to make enough difference that you could call it effective. In effect, you have only changed the location of the perched water in the container to a higher position.

B) If the perched water table was equal to the combined parts, we could guarantee excellent drainage in any soil by mixing in, say marbles, which have an effective PWT ht of zero. Obviously, if we mix equal volumes of marbles and a retentive soil that has a PWT of say 10 inches, the PWT is likely to remain at 10 inches.

The o/a size (and shape) of the particulates and the uniformity in size of the particulates is far more critical to drainage than just combining amendments that drain well with those that don't. Drainage layers don't have enough "wicking action to pull water from the saturated layer above. Only when the capillary pull of the drainage layer approaches that of the soil above, does the water move down. At that point, the soil above and below are essentially the same in water retention and porosity, so it actually is a homogeneous soil from top to bottom.

You need only look to geologic perching of water in clay or silt that rests atop sand or scree to see actual additional examples/evidence of the physics involved.

I may not have needed to detail this. I'm assuming you mean drain hole when you said wick hole? If not, the physics involved change, which is what makes the wick so effective.

There is an older thread, linked to in the original post above, that is maxed out. There are additional examples of this effect scattered throughout it.

The bottom line is, drainage layers offer no help in correcting soils that are too water retentive. Their value lies in the fact that they reduce container soil volumes, which reduces total volume of water in the container, not in improving drainage. It would still be far more effective to use more soil w/o the drainage layer, wick the unwanted water from the container, and later, stop wicking as the planting matures and more water is needed. For maximum plant vitality, it is important that air returns to soil quickly. Fine roots die soon after being deprived of O2, regardless of where the saturated layer is in the container. It then saps energy from the plant to replace lost roots.

I would also suggest that if any feel a drainage layer is needed, a close look should be taken at how appropriate the soil in question is for use in containers.


Al


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RE: Container soils and water in containers (cont.)

  • Posted by spmimi z6 (brooklyn) (My Page) on
    Wed, May 3, 06 at 23:19

for al, and anyone else, i have a couple of questions but i would like to preface my post with a big wow as i've been fascinated by this post (and the original post previous). i thoroughly enjoyed reading the science behind the art, and the well thought-out arguments in the debate. i have had relative success with my indoor houseplants for several years now, in the sense that my greenery always elicits many ooohs and ahhhs from family and friends who visit. what they don't know (and what i refuse to admit to them!) is that the reason my greenery looks so nice is because i routinely throw out plants i have killed by overwatering!!

so there, i admit it - i have killed my share of plants by overwatering, even the so-called "easy" plants. i own my responsibility for having a heavy hand, but i am also starting to think that perhaps my soil is too heavy and compacted, especially since i rarely re-pot. on the other hand, i have used the same commercial brand of soil for all my plants, and some drain much more freely than others (with the corresponding longer survival rate). at any rate, after reading through this and other posts, i am ready to take the plunge for bark!!

so i just have a couple of questions...

1. all my plants are small, no larger than a 10" container. are there are any concerns for transplanting in a bark-based soil? any tips or things i should be careful about? although i am excited to try this, i am still a bit anxious.
2. what if i recently re-potted a plant, say about 3 weeks ago? will it be too much shock to transplant again? do i need to wait until next spring for that?
3. because this is new for me (and for my plants), i wonder whether or not i should do the wick as well?
4. and if anyone is reading in the nyc area, if you have any suggestions for locations/brand of pine bark fines, please let me know!

any responses are much appreciated. for whatever reason, i always figured containers were just little miniatures of what is found in nature and that soil is soil and extra compost is good for everything. i am only now beginning to understand the difference between gardening with containers compared to digging in the earth. it's been wonderful learning from all of you!


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Thu, May 4, 06 at 9:47

1) You'll need to stay on top of watering. Well aerated soils that drain quickly dry quickly. Also, lots of fertilizer is carried out the drain hole. Here's the best way to water containers (houseplants included): In two steps, first lightly water your containers. Make another round and apply enough additional water so that about 10-15% of the total volume applied to that container escapes from the drain hole(s). Discard that water. This method allows most of the fertilizer to remain in the container for plant uptake, but still dissolves and flushes any accumulating salts from the soil.
2) If plant shows reasonable vitality, it should be no problem. If the plant is strained or severely stressed, I would wait. Though it is often suggested that houseplants be repotted when they are quiescent, I have found recovery to be infinitely quicker if they are repotted just before peak growth is expected. This is particularly true of trees grown indoors (tropical/sub-tropical).
3) As long as you're building a soil, build it so it doesn't need a wick. Wicks should be considered remedial for poorly built soils or for use as a way to get water into the soil (from a reservoir), instead of removing it.
4) Hopefully, you'll get response here. If not, I probably can chase up bonsai contacts in clubs there who will have the info. It may take a few days, though - they'll all be repotting evergreens now. ;o)

Al


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RE: Container soils and water in containers (cont.)

  • Posted by spmimi z6 (brooklyn) (My Page) on
    Thu, May 4, 06 at 17:40

thanks al. i really look forward to trying this new soil out this weekend (as long as i can find everything!)

just a couple more questions if you don't mind...

1. i understand ph on a very basic level for purposes of what particular types of acidity/alkalinity certain plants prefer. however, i am not sure why does this soil mix that you prepare need lime added to it? and with that in mind, how necessary is the lime? for instance, if i don't find lime this weekend, can i still go ahead with the mix or is there something crucial in this component?
2. when i transplant, should i try to get rid of all the old peat-based soil from within the root ball? i don't want to create this defining line of old soil and new soil composition; then again, i don't know how important that is. if i should try to go through the roots, how is it best to do this? besides a basic pulling through the edges of the root mass with my own hands before planting something, i've never really dealt with the roots before.

i know often this topic becomes a one-man show, but i do appreciate your patience and input!

cheers.


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RE: Container soils and water in containers (cont.)

  • Posted by spmimi z6 (brooklyn) (My Page) on
    Thu, May 4, 06 at 22:48

i'm sorry.... still one more question!

and also btw, i found the answer about the lime when i re-read that old long post (it adds calcium).

i'd like to make the mix this weekend but i'd rather use a seaweed elmusion rather than something from scotts, however i'm anticipating that i might have to order online.

so my question is whether or not i can mix the other ingredients (bark fines, peat, and perlite) and add the lime and micro-nutrients after i've planted? or is there something about adding all the ingredients in the initial mix that is superior in some sort of manner?


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Thu, May 4, 06 at 23:07

Spmimi - the lime is a valuable source of Ca & Mg, two elements almost always short in container soils, particularly the Ca, which is crucial to cellular well-being. Some/most fertilizers contain these elements, but often not in sufficient amounts. Oops - just saw that you got the answer to this already.

Difficult to answer how to treat roots of individual plants except on a plant by plant basis. Much depends on how the roots are structured. Many houseplants have very fibrous roots that can be dealt with by cutting a portion of the bottom off of the roots. Then, with a scissors, cut pie shaped wedges so that about 1/3 of the additional rootage is removed. At next repot, cut more wedges in a different place. At third repotting, remove wedges that contain the last of the old soil. This is a good way to keep many plants continually rejuvenated. Not something you're likely to see in a houseplant book though. ;o)

Sure, you can mix your soil and and scratch lime & micro-nutrients into surface soil later. Any controlled release fertilizer will perform best when incorporated into soils, rather than broadcast atop of soil.

Al


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RE: Container soils and water in containers (cont.)

Not sure if I am 'intruding' or not by posting this, but there are multiple ways of getting trace nutrients into potting mixes.

Lime adds calcium and dolomitic lime adds magnesium as well. The potential drawback of lime is that a few plants are very sensitive to it and it raises ph. In a container the ph rise isn't terribly significant over the long term unless you grow blueberries in containers like me ;-)

Some other ways to ensure your containers have ample micronutrients are:

Greensand: Primarily potassium, but it's also loaded with trace elements. It is considered very slow release.

Alfalfa meal: Primarily nitrogen, but it's also loaded with lots of trace elements.

Kelp meal and worm castings do not contain high amounts of the 'big 3', but contain nearly every trace nutrient. Additionally worm casings contain substances that stimulate plant growth. (I just started a worm bin to 'make' worm casings at home. It's fun)

Compost: Not high in any nutrient, but usually contains a lot of trace nutrients. Al doesn't like compost in containers due to it's small particle size.

Last, but certainly not least as far as calcium is concerned, egg shells. Leave them dry in the sun a couple days and then powderize them and sprinkle onto the potting mix and scratch in.


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RE: Container soils and water in containers (cont.)

  • Posted by spmimi z6 (brooklyn) (My Page) on
    Fri, May 5, 06 at 0:40

okay, remember when i said i only had one last question? i should have known that wasn't true!! but i think this is truly it! ;)

and of course, username, the more input the better so please don't feel like an intruder!

believe it or not, i just got back from a midnight shopping trip at lowes! and here are my last questions...

1. i know there's always a discussion about what "fines" are in the sense that there's nothing sold in a big bag called "pine bark fines" so people get confused about the nomenclature. after reading this and other posts, i came to understand that what is meant by this term refers both to the conifer source (e.g., any conifer would be okay) and to the particle size (e.g., no big nuggets). what i did buy was "cedar mulch", which i hope satisfies my (hopefully correct) assumption for a conifer and for the correct particle size (it looks the same as that posted pic example, just a different color because of the cedar). am i correct???

2. i am also of the understanding that the micro-nutrients are necessary for this kind of mix because of its very nature of being "soil-less" relatively speaking. lowes didn't have earthjuice, so i will have to get it from another source later on. however, i saw on the earthjuice website they have a separate general fertilizer and a micro-nutrient fertilizer. in the question of application, do you alternate the two or for simplicity sake, feed both at the same time? this is a new science for me as i have never used fertilizer before.


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RE: Container soils and water in containers (cont.)

  • Posted by spmimi z6 (brooklyn) (My Page) on
    Fri, May 5, 06 at 16:21

i wish there was an "edit" function, because i don't mean to create a whole new post... i just wanted to clarify about the cedar mulch i bought yesterday. i understand the need for fines to be based on particle size, so i thought the mulch would be okay since it is shredded finely (no nuggets) probably no more than 1/2". however, i have also read about the need for it to be "partially composted" and if i am understanding it correctly there is a difference between size and its composted nature. you can shred something smaller but that doesn't mean it has broken down compostically-speaking. so what gives? is my cedar mulch okay? i know this ain't rocket science, but even if i do use something different, i'd at least just like to know what its potential impact may or may not be.

sorry so long!


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RE: Container soils and water in containers (cont.)

I live in downtown Toronto and today I went looking for the ingredients Sphagnum Peat Moss and Pine Bark.

Canadian Tire on Yonge had lots of different mulch bags but none were "Pine". They had mostly "Cedar" mulch and "mulch" of unknown origin. So I didn't buy anything except a 2.2 cu ft of Sunshine Professional Growing Mix with ingredients resembling Al's mix! (peat, perlite, crf, dolomite lime, wetting agents) that cost $15 plus tax CDN.

The reason I didnt' buy the cedar mulch (nuggets or mini-nuggets) is I remember something about cedar being toxic in some way. Maybe I could be corrected on this!

I went to Sheridan Nurseries and it was similar story: cedar and fir mulch but no pine mulch. One employee said you can't grow in pine bark it's too acid and doesn't hold water but I didn't have time to explain, I went looking for the Loblaws at Lawrence Ave. Lo and behold they had vast quantities of pine bark mulch of the "No Name" Brand for $8 per 56 Litre bag.

From looking at the contents, I think it's precisely the perfect size and material. It looks a bit like on the photo posted earlier in this forum - the darker bark at the top - except it's not as dark, and it has lots of 1 inch gold-colored toothpick-size pieces of bark.

Now I will mix this pine bark with the sphagnum mixture, 6 to 1 ratio, and replant my plants in this. They are currently in 100% cheap garden soil that's hardenend and compacted. My 18 inch tomato plant looks healthy but worries me that she bent all the way down on its side last night, so hopefully she'll regain strenght in better soil!

Charles


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RE: Container soils and water in containers (cont.)

  • Posted by spmimi z6 (brooklyn) (My Page) on
    Sat, May 6, 06 at 22:43

well, if that's true, then i'm in some doo-doo because i re-planted everything this afternoon :(

i did some googling, and found that there are reports of the toxicity from cedar... but also from fir, redwood, pine and other barks. then again, it may all be a question of relativity and the acids in cedar are more toxic than the acids found in the other conifer woods. i can post links for anyone who cares to read the references.

well, it be great if anyone else had some clarification on this issue?

i'm foreseeing a busy re-re-planting for me next weekend! :(


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RE: Container soils and water in containers (cont.)

I have read that cedar is toxic, but I don't know if it is toxic to plants or just bugs/bacteria. I mean the reason why folks choose cedar for wood contacting the soil or outdoor furniture is it resists rotting due to whatever is in it that repels the rotting organisms.

If you have some links handy I would enjoy taking a look at them to better understand what it is about cedar that gives it the preservative effect.

I was going to caution you against using the cedar mulch, but stopped when I realized I really didn't know if it was toxic to plants. I have heard it is bad stuff to use, but I hear lots of things ;-)


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RE: Container soils and water in containers (cont.)

  • Posted by spmimi z6 (brooklyn) (My Page) on
    Sun, May 7, 06 at 11:35

well, the minute i hear something i don't know about, google becomes my best friend (after all, research is what i do). however, the science of toxicity is not in my repetoire, so although i can access various different papers and arguments, i have a more difficult time in the analysis of the findings.

since i have several links, i will have to cut/paste into my post rather than link directly....

pdf that speaks of the toxic acids within all bark (including pine, fir, redwood, etc) - http://www.lecooke.com/Nursery/Bareroot Care/toxic planting mediums for bareroot.pdf

descriptive that claims only cedar bark is toxic - http://www.ext.vt.edu/pubs/nursery/430-019/430-019.html

paper that argues cedar is not toxic - http://www.puyallup.wsu.edu/~Linda Chalker-Scott/Horticultural Myths_files/Myths/Allelopathic wood chips.pdf

and there are others, but these are the most concise. in all my readings, there is a 100% consensus about the allelopathic toxicity of black walnut; but as you can see from the one link, a little less consensus about cedar and its affects.

on one hand, i've been using cedar mulches on my perennial native gardens and have not experienced any negative effects (at least none that i can attribute to the cedar).

on the other hand, this is cedar in direct contact with the roots, which i may suppose have a different kind of affect, if any.

so i guess i'm at a point where i'm thinking... if some but not all folks think cedar is bad, then should i assume that the benefits of being more safe than sorry should outweigh any possible complications from re-potting twice in one week (e.g., any transplant shock issues)?

i know i'll have to make my own decision, but what are the thoughts here?


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RE: Container soils (addendum)

  • Posted by spmimi z6 (brooklyn) (My Page) on
    Sun, May 7, 06 at 11:56

is there any edit your old posts function here that i am missing?? i'm sorry to clog up this post!

but i wanted to answer your question about what is that makes cedar so rot-resistant. from my readings, cedar contains the oil methyl thujate, which gives it the preservative feature.

you will also see that thujaplicin is an acid in cedar wood listed as toxic. from my rudimentary chemistry education from years ago, i have to assume that the two are related, however someone please correct me if i'm wrong.


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RE: Container soils and water in containers (cont.)

Thanks for those links, I will take a look at them.

My initial concern regarding cedar in a potting mix wasn't so much direct poisoning of the plants, but potential poisoning of the bacteria in the mix which assists plants with growth and vitality which may lead to reduced performance or other issues. Again, I really don't know. Just talking out loud.


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RE: Container soils and water in containers (cont.)

Al,
AJ here! I thought I had checked the box on the post page to notify me of new posts to this thread, but apparently not! I finally checked back today and found that there have been LOTS of new posts!
Thank you for your reply. I will check my experiments again--maybe it is the mix I am using? I don't use a rock layer to improve drainage in a poorly-draining soil, I use it along with a good soil mix. I still saw more drain with the rock layer at the bottom, and I did mean "wick" hole and not drainage hole. I will try things again. I know you are MUCH more knowledgable about container growing than me (or pretty much anyone else!), so I take a lot of value in your opinions.
I am getting ready to go pot some tomato plants in my 5 gallon containers (way too small, really, but all I have). I am going to try your soil mix, as soon as I can figure out what you use for micro-nutrient mix---I know it's in one of your posts, I just have to find it!

Thanks again, Al!
AJ


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, May 15, 06 at 20:56

Hi, AJ. I use Micromax granulated nutrients by Scotts. There are other sources of nutrients that work well. Seaweed emulsions are good, Earthjuice is too. There are more and more fertilizers coming out that guarantee they contain all the minors. Another product I intend to try is STEM, a soluble source of trace elements.

Let me know if you wish to try the Micromax and do not have a source for quantities less than 50 lbs (around $80). I can put you onto a place that offers smaller amounts.

Take good care.

Al

Here is a link that might be useful: Micromax


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RE: Container soils and water in containers (cont.)

  • Posted by spmimi z6 (brooklyn) (My Page) on
    Tue, May 16, 06 at 11:13

hi al - i have a question if you don't mind. i know that you aren't one given to speculating conjecture without seeing the stuff first hand, but i am going to try to pick your brain anyhow! ;)

i made your mix with the aforementioned "cedar" mulch that resembled the photo of your pine bark fines. i had to double-check my rusty conversion methods, but everything was mixed in the 5:1:1 ratio you suggest. it was nice and fluffy and i was very excited, especially when i took out my plants and saw the old soil dark and compacted. i gave a first watering, and it drained very quickly. i was very excited!

but the soil seems to have remained wet much longer than i expected. i checked a day or two after the initial watering, and it was still very wet. it's now a week later and the top is dry, but if i stick my finger down about 1", it's just barely dry, to the point that i probably will wait a couple more days to water. this is not what i expected, based upon all the reading i did of various posts (from you and others) who have used this type of mix.

so here's where the conjecture comes in...

do you think it's simply very wet because i gave it a too thorough watering the initial time? or maybe i didn't mix it correctly? or maybe the "cedar" has properties that cause it to retain water? or there is something with my growing environment? or or or???

or maybe i'm just crazy? :)


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, May 16, 06 at 11:40

Can't really say w/o some idea of what the water retention of the wood product you used is. Many things influence how long a container soil remains moist. Air temp, air movement (wind), type/size/stage of development of plant material all impact the water retention. It shouldn't have anything to do with how you water. You should be able to water the soil thoroughly/completely each time you water. Water should run through the soil rather quickly & when you're done watering, a handful of soil, squeezed in your hand, should only yield a little water. I grow in a more highly aerated mix than I suggest here, because I know I have to water every day, & I like it that way.

It's not necessarily a bad thing if immature plantings stay wet awhile, as long as the soil isn't saturated & depriving the roots of air. Normally, the 5:1:1 mix yields a soil that drains faster than expected & takes some getting used to as it requires more frequent waterings. This is actually the first time I've heard it suggested it might be retaining too much water. ;o)

Al


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RE: Container soils and water in containers (cont.)

  • Posted by spmimi z6 (brooklyn) (My Page) on
    Tue, May 16, 06 at 12:48

you know us city folk, always trying to be different and contrary! ;)

thanks for the quick reply. if i do find pine bark fines, it will be interesting to notice any difference. i am sooo wanting a faster draining soil!!!


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RE: Container soils and water in containers (cont.)

tapla,
Hey Al,read the whole post original and cont.,(whew!).

Thank's for helping me re-think the container soil thing,all I've been reading is compost this,and compost that and as usual they grow,but less than optimum.

I have experimented with hydroponic(a long time ago),and your soil mix seems to be a "natural" soil-less/nutrient-less medium that simulates rockwool,i.e.,optimum root medium regarding areation.

But it seems with water loving plants as most are,would require constant watering once or twice a day.

So I was thinking...for those of us who want to grow a few maters',without watering manually,wouldn't your medium benifit from a water/nutrient resevoir(say 20 gallons with nutrient solution)that would drip/flush a gallon or so per pot twice a day and recycle excess back to resevoir?Then just refill the resevoir every other day or so,what do you think? Kind of an Al's soil mix/self watering system.

Timers and drip/flush irrigation parts are pretty cheap and you got me thinking!

Thank's for sharing your knowledge,and making me re-think my options!


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Jun 27, 06 at 20:29

If you intend to use the drip/flush method, you'd do well to grow in a mix that's very high in perlite or something like Turface or Espoma's Soil Perfector. The limiting factor for the openness (aearation/drainage) of my soils is watering frequency. My soils have to go a full day without irrigating & still keep the plant(s) hydrated. Since you'll be eliminating the watering frequency issue, why not go for a highly aerated mix like I described?

Al


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RE: Container soils and water in containers (cont.)

  • Posted by andy_e SF Bay CA 9/14 (My Page) on
    Wed, Jul 5, 06 at 14:36

Al,

I was finally able to find composted Redwood bark in my area...is it usable in your recipe if it's fully composted? This stuff is actually sold as "Redwood compost" and the label on the bag says it only contains composted Redwood bark.

Andy


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Jul 5, 06 at 19:03

Actually, fully composted redwood bark is rather stable & should be quite usable if particulate size (I would consider this the deciding factor) is suitable. The hydrocarbon chains in the cellulose will have been broken down leaving mostly lignin and suberin - compounds that are very resistant to the effects of microbial activity and the associated impact on soil collapse.

Al


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RE: Container soils and water in containers (cont.)

  • Posted by andy_e SF Bay CA 9/14 (My Page) on
    Thu, Jul 6, 06 at 12:06

Hmmm...well here is a picture showing the product. I don't think this will cut it as the particle size is more akin to that of a commercial potting mix. Do you agree?


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RE: Container soils and water in containers (cont.)

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

The product looks like it will be just fine in soils, though at first glance it seems as though it contains lots of sapwood. Btw - it isn't even close to fully composted. If I had to guess at a good starting point (mix) for your area, I would think 6-8, maybe even 10 parts bark, 1 part peat & one part perlite would be good. If it's not as hot and dry there as I'm thinking it is, then scale back on the bark.

Al


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RE: Container soils and water in containers (cont.)

  • Posted by donn_ 7a, GSB, LI, NY (My Page) on
    Thu, Jul 6, 06 at 17:39

Al and others...thanks so much for two hours of fascinating reading. I had started reading the original thread some time back, and just came back to it through this one. I think I'll have to read it all again, however, to be sure I got it all.

Andy..try sifting that stuff, and using the coarser stuff in your containers, and the finer stuff in your garden.


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RE: Container soils and water in containers (cont.)

Just wanted to say thanks for making this thread and the other one. Thoroughly enjoyed reading all the posts in both. Tapla, please move to Florida. :o) hee!


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RE: Container soils and water in containers (cont.)

Gurus are fine, but there are MANY gurus out there in every field imaginable, and their followers think they have found The Answers. I'd consider the credentials of any guru I chose to follow, and gurus in every field have wildly varying opinions about The Truth. I think it is more advisable to follow scientific evidence than a guru. University studies on horticultural claims are the best thing we have. They are not infallible, but at least they are objective and the conclusions follow rigourous double-blind tests.


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RE: Container soils and water in containers (cont.)

Why follow any guru, eldo? If you see something interesting try it out and see how it works for you.

This is gardening, not heart surgery. We don't have to get it right every time.

Personally I would never use Al's mix. Do I think Al is wrong about what he says? No, not at all.

Why wouldn't I use it? Because I use a mix that has me watering every 3 days instead of every day during the summer.

If I had to water any more often my plants would die from going 2 days without water.

If I had more time and could water daily would I use something akin to Al's mix? You bet.

Try it for yourself and see. That's the real beauty of gardening. We don't have to take anyone at their word, we can try things and see for ourselves.


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RE: Container soils and water in containers (cont.)

Why establish such a negative spirit in such a positive forum? Again? Al did not invent the science upon which his potting mix is based. He did not even invent the mix, really (just improved upon it). The science behind it is WELL founded in a million or so text books, should you so desire to delve into that field seriously. He has never professed to be a 'guru' (YOUR word), but is an amazing educator, experimenter, communicator, and.....friend to so many of us. I suggest you 'dig in' and appreciate those who give so much of their time, talent, and treasures to those who are interested. If you do a search on tapla in all of the forums, you would realize what he has given to us in information, time, instruction, and humor.

By the way, if you cling to 'university studies' without the ability to learn and grow as information is gleaned and expanded.....then I have several 1800 era text books you may be interested in. ;-) Al's information is based on the best, the newest, and the most sophisticated research.


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RE: Container soils and water in containers (cont.)

  • Posted by andy_e SF Bay CA 9/14 (My Page) on
    Tue, Jul 18, 06 at 17:40

Just wanted to report back in...I ended up using the redwood bark in an 8:1 mix with perlite. I'm not a fan of peat so I left that out. We'll see how it goes, but so far the drainage is nice - quite fast compared to my usual commercial mix. I don't mind the extra watering so it's all good.


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RE: Container soils and water in containers (cont.)

  • Posted by amyben 7 Bklyn., N.Y. (My Page) on
    Sun, Jul 23, 06 at 16:33

Hi container gardeners,

I'm so happy to see this thread continue, and have suggested Al's recipe to all my gardening friends. Having resolved to use it myself I finally found pine bark locally (Gowanus garden center, a tiny but precious lot on 1st. St. in Bklyn.). I was detirmined to substitute coir for peat because of its supposedly superior water retention and ability to not break down as fast as peat. I found it through discussion here at growstuffplus.com. This brings me, finally, to my question: do I still need lime? Coir claims to be less acidic than peat.

Thank you all, especially you, Al.

AmyBen


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Jul 24, 06 at 19:32

Your question including "less acidic" brings up the question of media pH. While the information commonly offered on many forums seem to indicate that container media pH in the 6.0 area is ideal, all the studies I've been reading indicate that more container plants do better in much lower pH media, with pH's even as low as 4.5 producing generally greater biomass in plants than the 5.8 - 6.0 "target" pH.

All that aside, the lime isn't included as something actually intended to raise pH, even though it can/does. The ideal concentration range of Ca in container soils is around 150 - 250 PPM. You'll find that bark-based container soils actually contain around 20 - 30 before supplementation. The ideal Mg range is around 20 - 80 PPM. Normally, raw bark-based container soils will have around 10 - 20, with aged bark yielding closer to ideal ranges than fresh bark. So, can you see now, why we might amend soils with an agent that supplies both Ca & Mg? - and why it might be needed, depending on your fertilizer regimen?

Al


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RE: Container soils and water in containers (cont.)

  • Posted by andy_e SF Bay CA 9/14 (My Page) on
    Mon, Aug 7, 06 at 2:56

Progress report on using "compsted redwood bark": I have found that this material becomes hydrophobic when it dries out, so unfortunately it's not going to work for me. I'm going to back to mixing perlite with regular potting mix until I can find something better.


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RE: Container soils and water in containers (cont.)

I would like to hear from others who have tried Al's recipe - how did it work for you?

It would be interesting to test plants in Al's mix against plants in reqular potting soil with perlite added, and double potted. Any one try a comparison?


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Aug 7, 06 at 21:01

Andy - regular potting mix, whether peat or bark-based tends to turn hydrophobic as it passes below 30% moisture content unless it's been treated with surfactants (wetting agents).

Al


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citrus in containers

Hi Al,i have killed a lot of dwarf citrus in pots by over wetting the mix and improper drainage(boggy soil).I read
somewhere that orchid mix is good to grow citrus in pots
because of the coarse pine bark and free draining mix.
Would you recommend this mix? Cheers


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Sep 5, 06 at 15:50

The richest mix (in organic component) I use for woody plants consists of equal parts of screened pine (or fir) bark, screened Turface (a baked clay granule that is very air and water porous), and crushed granite. This mix has about 70% total porosity and is about 30-35% air porous when at container capacity (when soil is saturated). It retains this structure indefinitely, even as the bark breaks down. It would be extremely difficult to over-water in this mix. The drawback to using it is the need to water and fertilize more frequently. It probably doesn't look like anything you've grown in, but I know several frequent readers/contributors of/to this forum grow in a similar mix with excellent results.

If you let me know what components you have to work with, I'm sure we can come up with a suitable soil, but more info is needed from you.

Al


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citrus in pots

Hi al,i have six dwarf citrus trees,I will transplant into 15
litre plastic pots as they are young trees under 1 metre
high.One was losing leaves from being in a soggy soil and i
have put a mesh at the bottom of the pot and used pure orchid
mix which looks like all bark to me.I have just bought a mix
for cacti and simulants(spelt wrong) which is a mix of different things but is supposed to be free draining.You
would have knowledge of this type of mix.I have noticed the
orchid mix is drying out nicely.All my other trees are
saturated in container mix.Your info has been very interesting to me.I would like to keep it simple,as i have
killed alot of trees.Are these mixes good with slow release
fert,which would you prefer? Cheers and thanks for your help
from new zealand where there is a lot of rain in winter!!


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Sep 6, 06 at 16:28

Well, the all organic (fir bark) soil would be OK for awhile, but will eventually be problematic in subsequent growing seasons. I use the inorganic components to prevent the soils from self-destructing over time. Peat, even bark-based soils are less than ideal for long term plantings because they begin breaking down quickly, eventually getting soupy or calcifying around the roots and creating watering issues (poor penetration into the rootmass).

This is a picture of the soil I might suggest for you. You can see there is little in the way of an organic component to break down. It doesn't really matter what the soil is made of, as long as it holds a reasonable volume of air, water, and nutrients for the life of the planting. I've settled on the mix I mentioned because it is extremely root-friendly, forgiving, and the components are easily had.

Yes, the mixes are good with controlled release ferts, but you should be ready to additionally supplement your trees with soluble fert(s) and a micro-nutrient source if your chosen fert does not contain the minor elements.

Al


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RE: Container soil for citrus

Hi al,I think these ingredients would be hard to find in
new zealand but i hear what you are saying.I was thinking of
using the orchid mix(which consists mainly of medium coarse
pine bark) with medium grade pummice.Would that help to conserve the condition of the mix.I would repot about every
two years i think.They are going into 15 litre tubs at the moment and they drain very well in just the orchid mix.I
presume the pumice would help preserve the mix?Anything else
you suggest i add,like perlite.I have chc chips 1/2 inch.
Heaps of those,how about i mix those with the orchid mix
and pumice?Thanks for your help Al.


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RE: Container soils and water in containers (cont.)

Hi,I also have coarse river sand(fine pumice)which i could
add to the mix if needed.cheers


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RE: Container soils and water in containers (cont.)

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

It's really difficult for me to help with anything but generalities here. The terms coarse, medium coarse, etc. are pretty relative and subjective, but size/texture and uniformity of soil particulates are essential in gauging the suitability of a soil's composition. Can you provide pics here or in my e-mail? It would be helpful.

Most river sand will have edges worn smooth, making it less effective at providing drainage and aeration, but some experimentation with particulate size and even the mix of sizes could provide you with one of the mineral parts of a long lasting soil. If the stone really is igneous (as you named it 'pumice') it should be air and water porous which may make it suitable as the only mineral component. No way to tell from here, but you will need a mineral component that is air/water porous or you will need to water and fertilize VERY often. 10-25 mm is about what you should aim for in mineral particulate size for your mix.

Al


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RE: Container soils and water in containers (cont.)

Hi Al,I bought some perlite today,a bag of orchid mix which has pine bark in the 10-25mm size,i have pummice stones as
described.The orchid mix contains blood and bone and dolomite
lime and slow release fert.Can i grab your e-mail and i will
send you a photo of these components.I couldnt find crushed
granite or turface(spelt wrong!)
1.composted pine bark with blood and bone/dolomite lime
2.perlite
3.pummice stones about the size of a pea
No peat or soil in this mix.
Does this sound ok ? thanks for your help


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picture above

Hi Al,can you tell me what the above mix comprises of and the
ratios please? I presume its turface,granite and bark?perlite?
I will try to search out these ingredients for my dwarf citrus
Cheers


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RE: Container soils and water in containers (cont.)

  • Posted by donn_ 7a, GSB, LI, NY (My Page) on
    Mon, Sep 11, 06 at 19:04

Al...I don't understand this:

"Most river sand will have edges worn smooth, making it less effective at providing drainage and aeration.."

I've use a lot of sand, for a lot of purposes, and it seems to me that the structure of sand implies that rounded sand when settled, leaves more air/water space than sharp sand. Rounded media cannot settle together as well as angular media, leaving more space for air/water flow.

No?


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Sep 12, 06 at 18:46

Hi Jonathan. I think I answered your questions off-forum, but if you have others, please don't hesitate to ask.

Donn - No. In almost every instance where a type of sand is recommended for use in container soils by a knowledgeable source, you'll see "sharp sand" specified. I even look at sharp (builder's) sand as largely inappropriate in container soils due to its small size. To me, an appropriate size 'sand' is 1/2 BB-size to BB-size. I bet you're thinking of something like a jar full of marbles as an example of the excellent structure you referred to.

In a perfect world, where all the particulates in a soil are the same size and shape, round particles are ok, but picture this:

Two different soils, both made up of three sizes of particles, but each of the three sizes in the different soils contains the same mass. Soil A) is made up of marbles, BB's, and 1/4 BB-size round particles. Soil B) is made up of the same material and each particle has the same mass as it's counterpart, only the shape is irregular. Which will drain better & better insure aeration? Now, introduce an organic component that breaks down into small particles over time.

Irregularly shaped particles in sufficient volume will always retain capillary tubes or pathways that allow water to flow through the soil. They also have a greater surface area for water to cling to, and more tiny pores than particulates that are worn smooth that hold water at container capacity and air as soils dry down. They also exhibit less gravitational migration or settling.

We cannot only consider how a particular group of soil particles relates to particles of the exact size and shape in a soil. We must consider what occurs at the interface with other particles in the soil for an o/a picture of a soil's performance based on its structure.

Al


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container mix for my citrus

Hi Al,the above makes intersting reading.I have not been able
to locate turface or crushed granite,ive tried everywhere
and its not available in new zealand.My grapefruit is definately suffering from soggy soil and dropping some leaves,
so i want to transplant asap.
The ingredients available to me are=
1.pumice between 5-10mm
2.pumice about half the size of the above
3.pine bark as per photo (quite large peices)
4.perlite
Found a bosai club but they use ordinary potting mixes.
It doesnt get really hot and dry here.It rains plenty in
spring,winter(very much).Highest temp humid 26c.We get a lot
of humidity.
I was thinking maybe=
3 parts medium pumice
3 parts fine pumice(this is not the river sand,same as above
but smaller)
3 parts bark
1 part perlite
How does that sound?
One last question = why does it say "pummice sand" on my big
bag of sand(coarse river sand).Looks like the sea sand style
to me.The one in the centre of my photo.Is that too fine to
use for my purpose and is it water/air porous?
I find that a bit confusing! Thanks for your patience!


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RE: Container soils and water in containers (cont.)

  • Posted by amyben Bklyn., N.Y. (My Page) on
    Wed, Sep 13, 06 at 10:18

You might try looking for a landscaper who reconditions baseball fields. They use a layer of crushed granite under the playing field for drainage, and Turface ( I bought it here under the name Pro's Choice infield conditioner, same stuff, nice red color) in the mix because it takes on water, then releases it back into the soil. You may also learn more than you thought you would ever know about baseball fields. Those little leaguers can't wait too long after a rain to get back to their game. (I'm assuming there's baseball in NZ)


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RE: Container soils and water in containers (cont.)

  • Posted by amyben 7 Bklyn., N.Y. (My Page) on
    Mon, Sep 25, 06 at 23:13

It seems like it's time to bring this information back to the top as required reading before building a container growing medium. I also want to mention that I think I'm going to be very happy having substituted coir for peat, although since it's now starting to get cool it hasn't been put to the test of brutal summer heat.


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RE: Container soils and water in containers (cont.)

  • Posted by amyben 7 Blkyn., N.Y. (My Page) on
    Fri, Oct 6, 06 at 19:52

O.K., Maybe I'm not so sure now about the coir, having read the Utah State University paper recently posted. But I am sure that Al's container soil paper needs to be near the top.
Amy


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RE: Container soils and water in containers (cont.)

I was wondering if I could get some help from some of the experts here on tropical plants. I am new to the forum, so "hi" to you all. I was wondering if Al's soil would be idea for tropicals. I have a couple of braided plants very similar to hibiscus, a cane, a couple of capella's, and another I really don't have a name for. I live in the Chicago area and I know winter is coming. So far this fall the humidity has been great with a lot of rain in the area lately and it has been 50% or above humidity in the house without a humidifier. These are indoor container plants and I get a pale green leaf once in a while and some turning brown on the edges once in a while. Anybody know something about tropicals?


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Sat, Oct 7, 06 at 21:19

Plantings are in constant flux, so if a soil is perfect today, it may not be perfect tomorrow when cultural conditions change or the planting matures, or for a whole lot of other reasons. Your job is to supply the best soil you can, and then tailor your watering practices so you "do no harm".

I have about 75 tropical trees and another 30-50 other assorted plants (indoors, under lights) in some minor variation of the same soil mix, which is equal parts of fir (or pine) bark, Turface, and crushed granite (see picture above). There are other components that will yield a perfectly serviceable soil, but I have been growing in this mix or some variation of it for many (more than 10) years & have found nothing better for tropicals & houseplants (and you can believe me when I say I have tried lots of different variations of soils).

The bark-based mix in the thread above should easily outperform a primarily peat based soil and retain suitable structure much longer than the peat soils, but the soil in the picture will out-perform the bark-based mix. The only downside, again, is the need to water & fertilize more frequently, but the return is a much wider margin for watering error and a high probability of superior plant vitality.

Al


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RE: Container soils and water in containers (cont.)

Ummmm, may I say that Al is under-emphasizing the plant vitality aspect of his mix. Judging by how my plants have done after being transplanted into his mix....you better STAND BACK and give them room! ;-)


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RE: Container soils and water in containers (cont.)

OK, my 'slant' is with regard to tall (6-8') plants in large (half barrel range) containers. I grow brugmansias which suck up water like crazy...requiring every other day soaks even when in the ground or these large containers w smaller containers needing daily water..
One concern for me might be whether this mix will provide enough of an anchor when these tall plants encounter a stiff breeze. The other is how fast the mix will dry out stressing these water hogs. The idea of improving the aeration overall for root growth is attractive but I'm wondering about how to avoid daily or more frequent watering which just isn't doable with a sizeable brug collection and a large yard 'otherwise occupied' with my other plant interests. I'll be using Al's recipe on my regular posts for thing like tuberous begonias etc. but would appreciate input on my brug challenge. Thanks in advance.


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Sun, Oct 8, 06 at 13:52

As in most soils, including in situ soils, anchorage is more an issue when the planting is immature. I grow lots of tall established plants that often topple readily in windy conditions, but generally: the plant blows over, a little soil is spilled, I return it to upright after the wind stops - replacing spilled soil, and the plant goes merrily along with no or minimal root disturbance. Taller immature plantings should be secured against movement (relative to the pot or container) anyway. I've found that woody material that is secured so the trunk does not move in the wind (breaking newly forming hair roots) establish in a fraction of the time it takes unsecured plant's roots to colonize the container.

When considering a soil, the speed with which the plant uses soil water can have a large impact on your soil choice. If your plants are using virtually all the water in the soil over a 12 hour period, the soil can have less porosity than it could in a planting where the soil water is only used .. oh, say every other day. In other words, total soil porosity becomes more important under these conditions than air porosity, so you can use a more water retentive mix and expect good results. I don't think it would be as good as a more aerated soil that is watered more frequently, but your situation might easily be viewed as one that requires some sort of compromise in the "watering frequency'" department.

Al


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RE: Container soils and water in containers (cont.)

Just wanted to comment that I have a small brug in a variation of Al's mix--being *unscreened* Turface and fir bark at a 7:3 ratio, no granite and the fir bark is chunkier and less uniform than the one he uses--and it is doing well. I do water it nearly daily but mostly b/c I don't need to worry about overwatering with this type of plant, with this mix, and the fact that I think it was a bit underpotted. On the days where I don't have time, it has not shown any wilting. I think not screening the Turface and eliminating the granite component has helped the media to retain a bit more water. I'm sure it has been mentioned already, but you can vary some of the components to modify the final product for both your needs and your availability of materials.

Al, did I ever formally thank you for the extremely practical information from this thread? If not, I would like to tell you that I certainly appreciate all the effort you put into this valuable summary, as well as all the time you spend answering queries. And Profile owes you :)


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RE: Container soils and water in containers (cont.)

Mantorvillian,

I do not know much about brugs but watering every other day sounds like the plant needs lots of water. How would that compare to my tropicals? I have had people talk to me so much about overwatering that I am afraid to drop any water in them. I have a couple of braided hibiscus types, a couple of capella types, and a messenga cane. They are all in range of 2 to 4 feet in good size pots. It is difficult for me to figure out if symptoms are being caused by overwater or underwater.


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Oct 10, 06 at 16:33

Visible symptoms of over and under-watering are usually so similar, it is impossible to differentiate between them. It stands to reason since the cause, a lack of water to the upper parts of the plant is at blame. In the case of under-watering, reasons are obvious, and in the case of over-watering, rotted roots make water transport to the top of the plant impossible. In this latter case, the plant literally "dies of thirst" in a sea of plenty.

Using a heavy soil that retains water makes your watering habits critical, while using an open or well-aerated soil that needs watering more frequently widens the margin for error & generally produces a more robust plant.

Al


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RE: Container soils and water in containers (cont.)

Al,

Thanks for your help. I thought I was doing fine with these tropicals for a couple of months watering them twice a week while they were in the old medium I was using, mostly peat and perlite. I started to see a couple of symptoms here and there and I think I might have panicked. I am a little picky so maybe I saw it as worse than it really was. That is when I ran into the over-watering people who convinced me my soil was too wet and I was rotting the roots. From that point as I cut back on the water, constantly checking the soil with a water meter that I think is very inaccurate, it seems as if the plants started doing worse. I now think I was not giving them enough water for the past month as the water meter may have been picking up on soil composition instead of moisture.

I am not a professional at knowing what rotted roots look like but when I repotted the roots looked just like plain old roots to me. The soil did contain a few pieces of stringy root parts here and there but all the plant roots looked as I would expect them to look.

I have since repotted using your soil mixture. I was pretty much inline with what you recommended using a quality sphagnum peat soil base and mixing it with extra perlite, a little lime, and a little nutrient, and then making that 1/3 of the mixture with 2/3's being pine bark.

With your soil medium now under my tropicals would you say that twice a week watering would be close to what I might be looking at? They are in clay pots glazed on the outside with two or three drainage holes each. 4 of the plants are 3 footers in 10 inch pots and 2 of the plants are 4 to 5 feet in 14 inch pots. I have a couple of wicks in each one going up 2 or 3 inches from the holes into the soil to help with drainage in those last couple of inches at the bottom. They all sit in platters and I never let the runoff sit in the platter. I have them indoors at about 50% humidity. I know it is hard to tell someone how much to water but I am only looking for a little something to go on. Thanks again and everyone else is free to chime in if they wish.


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Oct 10, 06 at 21:33

Hi Jimmy. Golly, I'd be the last one to suggest you water on any kind of schedule, although I can say the more open the soil is, the better the chances you can water frequently with impunity. Every plant is different. I would suggest you get a piece of dowel about the thickness of a pencil. Sharpen it in a pencil sharpener & use it to probe the deeper part of the pot. If it comes out damp - don't water, dry - do water. You'll soon get the heck of it & establish something of an approximate schedule that suits each individual plant. I know you wanted to hear something "easier", but this is my best advice.

Your "soil moisture meter" is a continuity tester & measures the flow of electrical current, and not how wet soil is. More metal salts (as in fertilizer or hard water) will cause a higher reading, even in drier soils. To prove this, insert the probe into deionized (distilled) water & note how "dry" the water is. ;o)

Al


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RE: Container soils and water in containers (cont.)

It is frustrating when you look at symptoms and possible causes. We all know the same symptons are always listed for too much water, not enough water, too much light, not enough light, too much fertilizer, and not enough fertilizer. I still feel that with my particular situation, knowing that I have not over fertilized the plants, that brown tips, holes, and seemingly dry leaves means lack of moisture, not too much. I could be wrong of course, but it is the feeling I get.

Here is another question I have pondered. What EXACTLY is indirect light? Tropicals call for indirect light because they are naturally found on the floor of the canopy they grow in. Does direct light mean sunlight hitting directly on the leaves and all other situations are indirect? I have all my plants at the north side of the house. Northern exposure is completely indirect because of my geographical location. The sun at it's highest in the summer of Chicago is straight above, so light comes in northern windows indirectly, as I would call it. The light itself comes through the window obviously, and will cast a shadow from anything it hits, including the plants. Does by the window and across the room both constitute indirect light? Light is hitting the plants, but you cannot see the sun from the position they are in. There seems to be a difference in what is taught on this subject.


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Oct 11, 06 at 15:58

Well, we're kinda straying off-topic a little here, and I sure don't mind, but technically I'm just a guest here because JD started the thread. He's cool, so I bet he doesn't mind. :o)

"We all know the same symptoms are always listed for too much water, not enough water, too much light, not enough light, too much fertilizer, and not enough fertilizer."

Actually, the over/under symptoms of light supply and of fertilization are quite different and easily seen by even an untrained eye when you know what to look for.

The term "indirect light" has little meaning for me and there's probably nothing "exact" about it. I always try to provide as much light as I can within the limits of the plants genetic tolerance (Unless there's a certain effect I'm trying to achieve - like an airy look or a more pronounced weeping habit.). I added "genetic" because tolerance to light extremes can vary widely by genetics within species. I suppose that technically, indirect light would have to be reflected, but I'm sure we can agree to include terms like diffused or dappled in our decision on what constitutes indirect light. Even light streaming through windows on a bright sunny winter day with the sun azimuth low is diffused and shaded by the glass it passes through. Usually, unscreened windows have shading co-efficients of 25% or more & 60% is not uncommon on windows with screens & special energy saving features.

I suppose it is probably a good idea to keep in mind that the amount of solar energy falling on photosynthesizing surfaces in tropical shade can be as much as what falls on leaves in full sun in my zone. I grow many plants (Ficus, Schefflera, some myrtles, Serissa) that are listed as "shade tolerant" or "indirect light suggested" in full blazing summer sun here in MI and the plants reward me with smaller leaves and tighter internodes which results in a more dense, fuller and bushier plant.

Al


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RE: Container soils and water in containers (cont.)

Jimmy_grow: Regarding the second paragraph of your post; visible light from the sun is divided into two components: direct beam and diffuse (or indirect in your terminology). Before sunrise, after sunset, or on days that are completely overcast the light is diffuse, there is no direct beam component. If one held up their hand to block the sun, the remaining light reaching your face would be diffuse coming from all parts of the sky. I hope this explanation helps.
agmet_al


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RE: Container soils and water in containers (cont.)

Al,

Let me ask you something. The ficus and schefflera that you mentioned that you have. Obviously of the tropical variety so this may help me. First, do you have them in a medium similiar to the one you have posted here. Second, how often do you water them?

I know, I know. There is no exact answer for frequency of watering, but I couldn't say whether I think twice a week or once a month is any different right now. I am just trying to get a general concept to wrap my mind around.

I got some sticks that go into the soil with a strip in them that goes from white to green when wet. Then it says they will become blochy over time and then turn back to white to let you know that water is needed. Well, you should know they don't exactly work that way and I should have known before I bought them.

How often are you dropping your H2O in the ficus and schefferella. Give me something.


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RE: Container soils and water in containers (cont.)

One more thing I was hoping someone could help with. Is it necessary to do any pruning with tropicals? What is the most likely cause of leaf loss? I have one plant that drops a couple of leaves that look healthy once in a while and another that has a couple of leaves turn pale green and yellowish once in a while. Is this normal?


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RE: Container soils and water in containers (cont.)

Jimmy, you would have a more likely response if you posted your questions under a brand new thread. This one on soils doesn't really address your present concerns and besides....the number of postings on this thread might keep people from looking at it. These last two posts you've made address good questions, and deserve their very own threads!

Just a suggestion.


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RE: Container soils and water in containers (cont.)

OK, here is a question in reference to containers and Al's mix. Anyone have any ideas on how often to fertilize and what type to use when applying to Al's soil mixture?


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RE: Container soils and water in containers (cont.)

  • Posted by amyben 7 Bklyn., N.Y. (My Page) on
    Mon, Nov 6, 06 at 15:02

It's time to send this article back to its rightful position at the top of the forum. We need it here through the winter so that, come spring, when the soil questions start popping up with the crocuses, the answers will be close at hand.


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RE: Container soils and water in containers (cont.)

Hi Al- I've spent most of today reading and digesting this thread. Its wonderful! I have some questions.

You mentioned that the soil mix you use is designed for those who are able to water at least once per day. Are there alterations that can be made to the mix for those who might need to water ever other day?

Can this mixture be used with emitter systems? Thanks for so much to digest during the cold winter months. Oh yes, once more question. Will alfalfa meal or rabbit poo harm this mix? If not, what percentage should I use?

The curious1


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RE: Container soils and water in containers (cont.)

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

You mentioned that the soil mix you use is designed for those who are able to water at least once per day. Are there alterations that can be made to the mix for those who might need to water ever other day?

Not really so. I think I said that I try to build my soils so that I need to water once per day in heat of summer when plantings are mature. I usually use a soil that is even more porous than the mix I offered the recipe for upthread. That recipe offers a reasonable interval between waterings, but it kind of depends on variables like o/a biomass of plant material in the container, "thirst" of the plant material, cultural conditions like wind - temperature - sun load etc. You could always try some of the starch &/or polymer water retaining products on the market (SoilMoist, e.g.) if you're thinking you need to further extend intervals between irrigation.

Can this mixture be used with emitter systems?

Sure. Usually more open soils seem to perform best when used with water emitting systems. Witness the media used in various hydroponic systems.

Will alfalfa meal or rabbit poo harm this mix?

I can see no advantage in using it, though I often find sharp disagreement on the use of things like compost, sand, manure, or other ingredients that break down rapidly or compromise aeration/drainage in a container. Container gardening is quite different from gardening in soil. There are many products, both chemical and organic, that will nicely supply the micro-nutrients that you're inquiring about w/o jeopardizing the aeration/drainage you're going through so much trouble to insure. Short answer: Not needed - I'd leave it out.

Al


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RE: Container soils and water in containers (cont.)

  • Posted by amyben 7 Bklyn., N.Y. (My Page) on
    Sun, Nov 26, 06 at 18:46

I'm showing my appreciation for this valueable paper by sending it back to the top for winter reading for newcomers. Al is either too modest, or not presumptious (enough).


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RE: Container soils and water in containers (cont.)

Q: Can this mixture be used with emitter systems?

A: Sure. Usually more open soils seem to perform best when used with water emitting systems. Witness the media used in various hydroponic systems.

I would have to disagree here. Drip irrigation is dependent upon capillary action to water evenly. The more 'open' the mix, the lower the strength of capillary action. The end result is the emitters drip the water out and it runs straight down to the bottom of the pot and out the drain hole. This is because of the weak capillary action of a loose mix.

The mixes with larger particle sizes and more open spaces are also poor in self watering containers for the same reason, poor capillary action. The water must wick upward in a self watering container and the more open the soil the weaker the wicking is.

An open soil is excellent for plant health and vigor, but it is most suitable to the 'traditional' container scenario where one hand waters from above. In this scenario the reduced capillary action is desired to avoid wet soil at the bottom of the container which holds little oxygen.

When using drip irrigation or self watering planters the more open soil simply doesn't have the same capillary action. A more 'typical' mix such as is found in any garden store/center works better due to stronger capillary action.

Drip can be used, but the number of emitters will have to be increased to provide even water coverage.

The same holds true with drip irrigation on the ground. A sandy soil (large particle size) requires closer spacing of emitters than a clay soil (small particle size).


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Nov 27, 06 at 19:12

Interesting that you have to disagree. Let's examine.

Drip irrigation is dependent upon capillary action to water evenly.
So is any form of irrigation other than total media saturation and subsequent return to container capacity conditions.

The end result is the emitters drip the water out and it runs straight down to the bottom of the pot and out the drain hole.
This would depend entirely upon how much water is supplied and at what intervals.

The mixes with larger particle sizes and more open spaces are also poor in self watering containers for the same reason, poor capillary action. The water must wick upward in a self watering container and the more open the soil the weaker the wicking is.
Soils with large particulate sizes are excellent in self watering containers. The strength of the capillarity of the medium is extremely unimportant as long as it is strong enough to wick water faster than the planting uses it. Though the o/a water-holding capacity is in part determined by particulate size, it is quite unimportant as long as an adequate supply of moisture is supplied. You seem to think that water movement upward through inter-particulate micro-pores is essential to the maintenance of adequate moisture levels, when in actuality, surface adhesion and water migration via intra-particulate porosity is entirely adequate to keep nearly any medium we'd likely be tempted to use adequately moist by wicking.

When using drip irrigation or self watering planters the more open soil simply doesn't have the same capillary action. A more 'typical' mix such as is found in any garden store/center works better due to stronger capillary action.
Maybe - maybe not. This statement is much to general to be given credence. As with all soils, watering technique and proper intervals are key, and open soils are far more forgiving when auto-irrigating. Consistent over-watering of a soil that likely has about 20% air porosity (most bagged soils) would carry severe consequences for plant vitality, while over-watering a soil with 35-40% air porosity at container capacity and 65-75% total porosity would have much less far-reaching consequence. This makes your supposition accurate only under a more limited set of conditions than would be true of a more open soil.

Al


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RE: Container soils and water in containers (cont.)

Okay.

I have to wonder if you have used drip irrigation or self watering containers.

Not trying to start an argument, but in my experience self watering containers and drip irrigation do not work well with loose, open mixes.

Drip irrigation can only deliver so much water per emitter and it doesn't spread very far in loose soils.

While a looser soil could be used in self watering containers one would have to 'mash' it down firmly for it to work well and that defeats the purpose in having an open soil.

Again, not trying to start an argument, but it doesn't sound to me like you have used drip or self watering containers much if you think they work ideally with these methods.


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Nov 27, 06 at 21:11

Readers of this forum have always proven to be quite intelligent, and are surely able to evaluate practical experience and what we have set forth - certainly no need for me to belabor a point. ;o)

Al


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RE: Container soils and water in containers (cont.)

Agreed.


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RE: Container soils and water in containers (cont.)

What a great topic. I always wanted to make my own potting soil. Jolly gardner in maine sells 1 cubic foot bags of acadia perenial pine bark mulch for 5.50 per bag. Acualy the sell to nurseries and they sell it for that. They have a web site jollygardner.com Sorry I dont know how to do a link. That stuff sounds like the stuff I need. It is composted. They also sell pine bark mulch that is not composted. If I read correctly Al prefers that? I might try both. Should the perlite I buy be the coarse stuff? And for the Micro N could I just use one gallon of good compost Rather than manure? Also what kind of controled relese F should I buy? I hope these questions were not already covered. Cant wait to do this. Thanks.....


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Dec 18, 06 at 17:47

I generally prefer partially composted bark in all my short term plantings and uncomposted bark in plantings I don't intend to repot after the initial growth cycle. Roughly translated, this means that I like composted bark for the "pretty stuff" (floral display containers) and uncomposted pine or fir bark for the long term (usually woody plants) that will not be repotted until after the second or possibly third growth cycle, but you certainly needn't be so critical.

I always use coarse perlite (or medium, if for some reason I cannot locate the coarser product). I'm currently using a 12 month controlled release fertilizer (a German manufacturer) that I got from a wholesale supply house, but any brand will probably work well. The formulation would depend on things like your temperatures, plant material, and what your soil is made of. Soils comprised of uncomposted organic particulates generally require the application of more N, so for those, choose a fertilizer with a higher N content than for soils with partially composted materials in them.

I avoid garden compost in my soils. There is a difference between composted bark and compost. Composted bark, particularly conifer bark, has a high lignin content and is rich in suberin. Lignin is quite stable, and is what is left of wood after the cellulose is "eaten up". Suberin is a lipid, concentrated in bark, which makes it very difficult for micro-organisms to cleave hydro-carbon chains in organic matter, which additionally adds to bark's stability.

Compost adds very little to container soils in the way of micro-nutrients. Instead, seek out a fertilizer that contains the minor elements, or use any one of a number of either organic or inorganic supplements. Fish/seaweed emulsions, Earth Juice, STEM, or Micromax (to name a few) are reliable sources of the minors and I much prefer them to pore-clogging garden compost. Since I wrote the article (several years ago) I've also stopped adding any manures to container soils for the same reason (reduces aeration by clogging pores and slows drainage), as well as the fact that you often introduce many unwanted weed seeds in the manure.

Al


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RE: Container soils and water in containers (cont.)

Thanks for such a detailed response. I have learned alot from you already. So I would use composted mulch for my annuals, like morning glorys, moon flowers ect... And uncomposted for clematis, roses, jasmine ect....? Thanks Al....Filix


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Dec 18, 06 at 20:47

Nothing need be so rigid as that, Filix. I just relate what I have learned & what works best for me. As I relate it, I try to be sure that science supports it and my conclusions are largely free of post hoc fallacy, so common in these forums. Please, draw your own conclusions based on what you observe in your growing efforts, perhaps only using my observations as something of a base from which to begin your own explorations.

May I suggest that you start by settling on a soil you can replicate consistently and the components of which you can obtain easily and inexpensively? From there, you can easily expand into the area of building soils that are individually suited to a particular planting if you prefer. The basic mix with pine bark, perlite, and peat as the primary components is a good starting point.

Good luck - and btw, we all learn when you ask questions, myself included. ;o)

Al


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RE: Container soils and water in containers (cont.)

What do you do with the soil you made for one years use? Can you bring it back somehow. Or just dump it in the compost pile?.....Thanks....Filix


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Dec 18, 06 at 21:50

There is wide disagreement on this point, but I never reuse it, turning it into the garden or on the compost pile instead. Others reuse it.

If you use the search words "tapla reuse" on this forum's search function, without the quotation marks, you'll be able to read other's comments about reusing container soils. Here is my opinion:

In my estimation, the only case to be made for reusing container soils is one of economics, and you'll never find me argue against making that decision. If you can't afford, you can't afford it. That said and setting economics aside, you might decide to reuse soil for reasons other than economical. Perhaps the effort involved with acquiring (or making your own) soil is something you might not wish to go through or be bothered with.
In any case, it would be difficult to show that soils in a more advanced state of structural collapse can somehow be preferred to a soil that can be counted on to maintain its structure for the entire growth cycle. So, if the economic aspect is set aside, at some point you must decide that "my used soil is good enough" and that you're willing to accept whatever the results of that decision are.

All soils are not created equal. The soils I grow in are usually pine bark based & collapse structurally at a much slower rate that peat based soils, yet I usually choose to turn them into the garden or give them over to a compost pile where they serve a better purpose than as a container soil after a year of service. Some plantings (like woody materials and some perennials) do pretty well the second year in the same bark-based soil, and with careful watering, I'm usually able to get them through a third year w/o root issues.

Watering habits are an extremely important part of container gardening. Well structured soils that drain well are much more forgiving and certainly favor success on the part of the more inexperienced gardeners. As soils age, water retention increases and growing becomes increasingly difficult. If your (anyone's) excellence in watering skills allows you to grow in an aging medium, or if your decision that "good enough" is good enough for you, then it's (your decision) is good enough for me, too.

The phrases "it works for me" or "I've done it this way for years w/o problems" is often offered up as good reason to continue the status quo, but there's not much substance there.

I'm being called away now, but I'll leave with something I offered in reply on a recent thread:
"... First, plants really aren't particular about what soil is made of. As long as you're willing to stand over your plant & water every 10 minutes, you can grow most plants perfectly well in a bucket of marbles. Mix a little of the proper fertilizers in the water & you're good to go. The plant has all it needs - water, nutrients, air in the root zone, and something to hold it in place. So, if we can grow in marbles, how can a soil fail?

Our growing skills fail us more often than our soils fail. We often lack the experience or knowledge to recognize the shortcomings of our soils and to adjust for them. The lower our experience/knowledge levels are, the more nearly perfect should be the soils we grow in, but this is a catch 22 situation because hidden in the inexperience is the inability to even recognize differences between good and bad soil(s).

Container soils fail when their structure fails. When we select soils with components that break down quickly or that are so small they find their way into and clog macro-pores, we begin our growing attempts under a handicap. I see anecdotes about reusing soils, even recommendations to do it all over these forums. I don't argue with the practice, but I (very) rarely do it, even when growing flowery annuals, meant only for a single season.

Soils don't break down at an even rate. If you assign a soil a life of two years and imagine that the soil goes from perfect to unusable in that time, it's likely it would be fine for the first year, lose about 25% of its suitability in the first half of the second year, and lose the other 75% in the last half of the second year. This is an approximation & is only meant to illustrate the exponential rate at which soils collapse. Soils that are suitable for only a growing season show a similar rate of decline, but at an accelerated rate. When a used soil is mixed with fresh soil after a growing season, the old soil particles are in or about to begin a period of accelerated decay. I choose to turn them into the garden or they find their way to a compost pile.

Unless the reasons are economical, I find it difficult to imagine why anyone would add garden soils to container soils. It destroys aeration and usually causes soils to retain too much water for too long. Sand (unless approaching the size of BB's), has the same effect. I don't use compost in soils because of the negative effect on aeration/drainage. The small amount of micro-nutrients provided by compost can be more efficiently added, organically or inorganically, via other vehicles.

To boil this all down, a container soil fails when the inverse relationship between aeration/drainage goes awry. When aeration is reduced, soggy soil is the result, and trouble is in the making."

Al


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RE: Container soils and water in containers (cont.)

I had a thought. I have a friend that owns a saw mill. He has mounds of white pine bark, with some hemlock. I own a chipper/shreder. I wonder if I couldn't grind up and sift my own. Are there insects in pine bark that would be a concern? Do the people who sell the stuff do anyhting to it to get read of any insects? I have a pickup truck. Mmmmmm. come on spring....Filix


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Dec 19, 06 at 17:58

Go for it, but you may wish to avoid slashings that have a considerable amount of sapwood attached to the bark - or bark to sapwood, depending on your perspective.

Insects that make their home in the bark of living trees would not normally be of particular concern in soils.

Al


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RE: Container soils and water in containers (cont.)

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 action.
When you buy a bag of pine bark mulch, don't you get both small particles and large? I would like to know because I bought a pickup truck load of pine bark mulch. It is about two months old. I will let it age until may. Then I will sift it through a screen with 1/2 holes. Do you think I should have another finer screen below to let smaller particles pass through. Or is this spliting hairs? Thanks


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Dec 27, 06 at 16:13

The highly irregular shape and generally larger particulate size of conifer bark mulch tends to improve drainage in spite of the mix of particulate sizes. You can "fine tune" the amount of air held in the media and drainage speed by adding more or less perlite. Here, it's good to remember that any media will break down in size (compact) over time. Peat based mixes break down at a far more rapid rate than bark-based, and soils with a lower organic component at a slower rate than either. This is why I chose to grow long-term plantings (including house plants) in soils that range from 0 to around 40% organic parts.

If you are screening your soil, I would add what remains above the .5 inch screen to the garden or beds and use what passes through it in your soils. If you feel you have an extremely high % of fines, you could screen it through insect screening & turn what passes through into the garden, but I don't bother with this step for short term plantings, choosing instead to add a little extra perlite if I'm concerned.

Al


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RE: Container soils and water in containers (cont.)

Thanks again Al. Im chomping at the bit to do this.


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RE: Container soils and water in containers (cont.)

Al,

I think you have done more research on various potting mix ingredients than I have and so I am wondering if you have enough info readily available that you could post something akin to a handy chart regarding the properties of various mediums?

I am not asking you to do a ton of research, just if you have the info handy.

For example the turface/profile makers have compared turface/sand mixtures to sand/peat mixtures on golf courses and have statistics regarding drainage rates, water holding capacity, aeration, CEC, etc.

One can conclude from this that turface holds less water than peat, but has better drainage and aeration. Turface also degrades much more slowly.

What I would love to see, if you have the info handy, would be a chart comparing various ingredients in terms of longevity (how long they take to degrade into too small a particle size), aeration/gas exchange, water holding capacity and CEC.

Any other info you consider relevant would be good as well.

Again, only if you have the info handy, I certainly wouldn't expect you to have to look this stuff up.

It could be very handy for those trying to choose an 'ideal' mix that best meets the needs of the plant as well as the grower.


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Thu, Dec 28, 06 at 0:46

Gee - while I appreciate your confidence, I already spend a good amount of time answering questions in my e-mail, plus that time that I spend here for the fun of thinking I might make some difference to a few folks. I suppose I should say that while I know how all these materials perform from having used them for many years, I'm not really willing to start building charts & graphs for things that you could easily research on your own.

Very respectfully, I'll say that if you have a specific question, I'm more than willing to answer it to the best of my ability, or even to go looking for the answer, if I don't know it, but to ask me to start to compile research that is not likely to be used anyway, is asking much.

If you were a member of the "Container Gardening Club", and you came to me (just pretend I was head of the program committee) with your request. I would say, "Dave (that's your name - right?), I think you have a good idea here. What I think you should do is research this yourself and put it in a form that is understandable and present it to the club at a future meeting. What month would you like to do it? You do know, that the person putting the program together learns more than anyone - right?" ;o)

Al


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RE: Container soils and water in containers (cont.)

Gee - while I appreciate your confidence, I already spend a good amount of time answering questions in my e-mail, plus that time that I spend here for the fun of thinking I might make some difference to a few folks.

You do make a difference and your efforts are not wasted. I completely understand your not wishing to undergo the effort of such a compilation. That is why I said 'only if you have the data handy' or something similar.

In other words if you would have to go hunting around and taking a large amount of time to consolidate the data into hard numbers I would consider it an unreasonable request.

I just thought that since you have clearly done a lot of homework you might already have the notes handy ;-)

I suppose I should say that while I know how all these materials perform from having used them for many years, I'm not really willing to start building charts & graphs for things that you could easily research on your own.

I totally understand, but at the same time as I read through your posts and Rhizos I see the 2 of you saying the same thing repeatedly, in fact I see that you in particular are obviously saving some of your more detailed posts and then cut/pasting them as replies to repeatedly asked questions.

This is a good technique to provide the info in a manner that conserves your time. However, building a potting medium that is ideal for both the grower and the plant takes a good deal of knowledge and it seems to me it would be a helpful thing to reference if the various relevant properties of the container media choices were presented in an easy to understand form. Perlite and turface both provide a good amount of air spaces between particles, but turface has more spaces within the particle to hold air and moisture. Turface also has an ionic charge that allows it to retain many nutrients well and perlite does not. Peat and turface both offer somewhat comparable aeration when fresh, but peat rapidly breaks down to hold more water and less air than turface. This kind of thing is what I am talking about. Putting it into a chart form would be a handy reference.

Very respectfully, I'll say that if you have a specific question, I'm more than willing to answer it to the best of my ability, or even to go looking for the answer, if I don't know it, but to ask me to start to compile research that is not likely to be used anyway, is asking much.

I agree, it is asking a lot. If you don't already have the info compiled in a form you could just copy and paste then it is asking way too much, I just thought I would ask if you had already possessed the info in such a form or a form that could be whipped into shape with little additional effort.

You seem like a geek to me (that's a compliment) so I thought there was a reasonable chance you would have the info in a copy/paste form or close to it.

If you were a member of the "Container Gardening Club", and you came to me (just pretend I was head of the program committee) with your request. I would say, "Dave (that's your name - right?)

Dave? Dave's not here, man. ;-)

I think you have a good idea here. What I think you should do is research this yourself and put it in a form that is understandable and present it to the club at a future meeting. What month would you like to do it? You do know, that the person putting the program together learns more than anyone - right?" ;o)

Nah, too lazy myself. ;-)

And I certainly do not expect you to do it either.

I was just asking if you already had the info handy to present in a form that could later be referenced to handle the questions many ask here.

Plus, I would rather you do the work than me ;-)


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RE: Container soils and water in containers (cont.)

Al what kind of controled release fert. do you use. Im getting all my ducks in a row. I have my pine bark, coarse perlite, peat moss, dolomite lime in granular form[ is that ok]? And now i found c,r.f. What I found comes in pellets That you put near the roots, just one I think. I found scotts micromax. But in a very large bag for around 70 bucks. Does it come any smaller. Hope Im not a pain..filix


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Fri, Dec 29, 06 at 17:11

I use a German import I buy in large bags from a wholesaler, but it's roughly the same as Osmocote 19-6-12.

Some of the large pelletized products are not controlled release, and even products labeled controlled release are very temperature dependent. please read the product info carefully so you don't over-fertilize,

Contact me off forum for more info on smaller quantities of Micromax (or STEM), please.

Al


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RE: Container soils and water in containers (cont.)

Well I have spent New Years Eve reading this entire post and enjoyed it more than most of my other years! I do have one question.
I am wondering what you use for a wick. And do you use the wick to water the plant or drain water out? Thanks for all the info!


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RE: Container soils and water in containers (cont.)

Justadncr,

I have replicated Tapla's wick experiment using Promix and CHC, and as a wick, I used a thin strip of an old towel...it worked very well. The wick serves to drain the perched water table out of the container.

As an aside, a nurseryman friend of mine uses wicks in a different way. He inserts a 2-3" piece of 1/4" nylon rope into the center hole of each pot. Then the pots are place on sand beds, large beds with about 6" of sand, covered with landscape fabric, and irrigated with a float/valve system. The pots are placed on the fabric (and ideally never moved again until sold) and the wick draws the water into the pots. Believe it or not, this is sufficient to irrigate hundreds of plants per bed with no overhead watering. Fascinating system.

SB


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RE: Container soils and water in containers (cont.)

I have learned so much this topic. I read it also last night for the second time. I have a freind who has been gardening for many years. He does alot of window boxes. Every year he plants the same geraniums. Most of the boxes are right under the drip edge of the house. So the plants get way too much water. Half way through the summer the ones under the drip edge look very bad. Those plastic inserts he puts in the window boxes are held up by two 1" pieces of wood. He needs to put alot more holes in them, add a wick and some screen to keep the soil in , and maybe change to al's mix. He uses farfed's mix. [ can't spell]

Im going to try al's mix in my morning glorys. I have been growing them for many years with some pretty good results. I was always told to just grow them in plan dirt. But im sure they would like some air for their roots. They couldn't have been getting much from just top soil.


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Mon, Jan 1, 07 at 14:09

Justadncr - not much to add to Stressbaby's reply except that it is rather immaterial what material you use as a wick when you employ it to remove water from containers - it only needs to be mildly absorbent o/a. When employed as an irrigation aid however, it does need sufficient absorbency to raise water to the soil level in the container via capillarity. I have a few plants I grow on an irrigation mat because the containers are so small they cannot go 12 hours without watering. I dangle a small wick on the mat & the plants remain "self-watering" as long as the mat is wet. This is the method that Stressbaby describes, using the wet sand.

Filix - The number of holes in the bottom of a container is unimportant. One, unclogged hole at the lowest part that collects water is as effective as 20 holes (with drainage as the consideration). Plants don't care if it takes a minute or an hour for soils to reach container capacity (drain). The addition of a single wick would be far more effective than drilling 100 holes in the bottom.
However, it is very possible, even probable, that plants grown under the eaves would have fungal issues from water continually dripping on foliage or from water hitting soil splashing up on leaves & carrying soil-born pathogens with it. Your friend should guard against this occurring.

It's good to always remember that air is as important as nutrients and water to plant vitality, so "plain dirt" will inevitably be a poor choice as a container staple due to its want of air-holding ability.

Al


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RE: Container soils and water in containers (cont.)

Thanks Al. Yes I can see now how plain old dirt is a poor choice. I dont know what Would help my freind. Potting in pure perlite or tuface? That would stop the splash and would drain fast. Geraniums from my experince hate wet feet. He has some under his overhang that gets no rain. Sometimes when I check on the place for him those plants are dry as a bone. But are full of blooms very healthy.
Why is it better to water from the bottom? Or is it?


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Jan 2, 07 at 18:03

I'm not sure that potting in perlite or even Turface is your answer. It would likely raise issues with required watering intervals and the Turface could get expensive when used in quantity as a soil.

Wick-watering from the bottom has both advantages and disadvantages. It helps reduce the compaction associated with frequent water flow through the soil, and tends to keep soil more evenly moist than the dry/saturated/dry/saturated cycle we often see when we irrigate heavy soils from the top. On the downside, wick watering tends to concentrate in soils, those solutes that remain after water evaporates. High concentrations of "left behind" metal salt precipitants can eventually make water absorption by the plant material difficult or impossible (plasmolysis). Plants could possibly die of thirst with roots awash in water. For this reason, I would suggest that even wick-watered soils are open enough to allow frequent flushing by a copious irrigating from the top.

Al


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RE: Container soils and water in containers (cont.)

A couple of questions. 1 Im interested in the concept of driling holes at and near the bottom of your wooden containers to encourage for air. I will be making some wooden containers.
2 Since we know air for roots is very important in containers, how about the ground? Some say not to ammend the ground. Just plant it in the hole you dig and put back the soil that came out of the hole. Because if you add things to the soil eventualy the roots will grow out of the ammended soil and be shocked with the soil around the hole. This is kind of confusing to me. Isn't a raised bed a large container? Why wouldn't the same thing for containers work in the ground?


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RE: Container soils and water in containers (cont.)

1 Im interested in the concept of driling holes at and near the bottom of your wooden containers to encourage for air. I will be making some wooden containers.

That's what I do, drill holes in the sides of the wooden containers. Something I am considering is adding a PVC pipe with holes drilled in it and covered with landscape fabric. The idea would be to make it easier for oxygen to enter otherwise impenetrable sidewalls. Of course if the wooden container is whiskey barrel like where there are small spaces between wood slats, this goal is already accomplished, but could be further improved, I believe, with an aeration tube. The idea is similar to what some do with compost piles where they want to maintain good aeration throughout, but don't wish to turn the pile often.

Some say not to ammend the ground. Just plant it in the hole you dig and put back the soil that came out of the hole

The only time I have heard this said has been in reference to trees which put out extensive and deep root systems. The expressed fear is that hard clay soil can act like a container if the growing media for the young tree is soft. I don't know how true this actually is, but if you think about it, it is kind of pointless to try and dig out a 10' diameter area 10 feet deep to improve the soil for a tree.

Isn't a raised bed a large container?

Sure is. The difference is that in most cases the 'container' is open on the bottom and in contact with the soil below. This makes drainage less of a concern than it would be in a closed bottom container not in contact with the ground.

It's that whole 'wicking' and 'perched water table' thing.


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RE: Container soils and water in containers (cont.)

Thanks justa. I like your idea on the pipe. If im going to make wood containers, I my's well make em right. I want to make some that would hold large canna. Like musafolia. Since I have never grown them before, I don't know how deep to make them. I know the rizhomes get put under the soil 2 or 3 Inches. But how deep will the roots get? I was thinking of 20" wide 24" deep. Same for clematis. Just I would do the woody mix thing for the clems, 1. turface 1.bark 1. crushed granite.
Would you put the perforated pipe in the corners verticle? Maybe it could take up air from the bottom also like a chimney effect. Would you go the full hight of the box?


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RE: Container soils and water in containers (cont.)

Shrubs and trees do best in the long run if you don't amend the soil ONLY if you are planting 'hole by hole'. If you are going to prepare an entire bed, raised or otherwise, then by all means...amend to your heart's content.

The reasons for not amending are simple, once you think about it. Plant roots will tend to grow into an area best suited for them....plenty of air, available water and dissolved minerals, etc. An amended soil is often an 'improved soil', and those roots are quite likely to grow round and round and round within that planting hole, becoming quite literally pot bound within the soil! I've lost count the number of times I've had to point that out as the reason a client has lost a shrub or tree.

Also, because the texture of the improved hole and the surrounding soil may be very different, the hole may either attract water to it or repel it. Either one bodes severe problems for the root systems of our woody plants.

Tree roots, by the way, do not put out extensively deep roots. (myth) The most important part of their root system is very close to the surface of the soil, where the highest concentration of oxygen is. The typical root system is very wide spreading, but very shallow.

By the way, I live in an area with very hard, red clay. The same rules follow for this kind of soil, too. No amending upon planting.


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RE: Container soils and water in containers (cont.)

If im going to make wood containers, I my's well make em right. I want to make some that would hold large canna. Like musafolia. Since I have never grown them before, I don't know how deep to make them. I know the rizhomes get put under the soil 2 or 3 Inches.

It's somewhat difficult to answer a 'how wide' question regarding container cannas because some will produce more rhizomes than others. There are cases where people placed a single canna in a 10" container and the container cracked from the pressure of the expanding rhizomes.

I my case I usually cluster 3-4 cannas together in a 22" container. It is 18" deep. The rhizomes are generally filling the width of the container by end of season, but I don't believe I have found them more than 10" or so down. Your mileage may vary.

Would you put the perforated pipe in the corners verticle?

I dunno, I haven't finished 'thinking about it' yet ;-)

My original thoughts were to place it horizontally, but vertical may have advantages as well.


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Jan 3, 07 at 18:10

The idea of multiple holes in containers and aeration "devices" is addressed in this thread or the last where water movement in soils was the subject. It seems an ineffectual effort to me. The only soils it could help are those that already have gas exchange occurring and don't need it. Those in which no gas exchange occurs will not benefit because it doesn't improve gaseous movement through soils.

Think of it this way: If you poke 1,000 holes & insert 25 perforated tubes in a tub of puddin', and do the same to a tub of marbles, which would benefit from the added gaseous exchange? Certainly not the puddin', and the marbles don't need it. The point is that any soil that is structurally able to benefit, already doesn't need it.

The only benefit of adding more holes and a perforated tube is that it increases evaporative surface area & soils dry down quicker. This decreases watering intervals, allowing us to "flush" stagnant gasses from soils at each watering, if soil structure allows copious watering, (it certainly should, but if it does, the tubes and holes are unnecessary) and allows some additional air to return to soils as they dry down (which would already have been present in any suitable soil).

I just wanted to note that growing in raised beds in not like growing in containers. It is like growing in the ground, but with better drainage (or soil), and quite different than container growing.

Al


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RE: Container soils and water in containers (cont.)

Al, the purpose in the aeration tubes, at least according to my thinking, was to increase evaporation in the perched water area.

I do not prefer light soils as I do not prefer to water every day. I am willing to live with the results of that.

At the same time, I do value good aeration and the potential for healthier plants.

I don't see any reason to have a soggy area persist at the bottom of the growing media. If I didn't want the entire height of the medium to be equally useful I would fill it with crushed aluminum cans or some other such material.

To my thinking the aeration tubes are a means to get better productivity from heavier soils while not significantly decreasing the watering interval. Or at least I hope it ends up working that way ;-)


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RE: Container soils and water in containers (cont.)

I just wanted to note that growing in raised beds in not like growing in containers. It is like growing in the ground, but with better drainage (or soil), and quite different than container growing.

Would you use same basic soil as containers?

Since a taller pot is better. More room for roots and lower p.w.t. I should make them accordingly.

I try to use rain water when ever I can. Catching it with a large plastic drum from the drip edge of my barn through insect screen.


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RE: Container soils and water in containers (cont.)

Would you use same basic soil as containers?

Not usually. Then again I don't use soil in my raised beds, I use peat, vermiculite and compost ;-) I have used a mostly compost/peat mix in closed containers that I flood with water, but that isn't the norm.

Raised beds with open bottoms will drain much faster than a closed container with the same growing media. This assumes, of course, that the earth the bed is on isn't water saturated.

Think of the earth as a great big wick.

If you use a fast draining container mix in a raised bed you will need a drip system with a timer and backup timer to keep the thing watered often enough. May as well switch to hydroponics at that point. Or start a cacti/succulent bed.

If you use a heavier mix more suitable for raised beds in a container you will have a drainage/aeration issue.

Having said that there are those containers growers who grow in pure compost in beds and containers who say they are happy with the results. To each their own, I guess.


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Jan 3, 07 at 20:11

Justaguy - The tubes will decrease soil volume and increase evaporation; both shorten watering intervals. So now you have a heavier soil than you want (otherwise, you'd have no need to resort to mechanics to increase aeration), a reduced volume of soil, and shorter intervals between irrigation.

Your "I don't see any reason to have a soggy area persist at the bottom of the growing media." tells me that you feel the tubes are an effective solution to persistent PWTs. Not so. The PWT in any container soil is of consistent height when soils are at container capacity.

A more open or just a more appropriate soil, and the simple addition of a wick are two more appropriate solutions, neither of which require diminishing soil volume and in most situations, no decrease in irrigation intervals.

Filix - Because of the constant wicking effect of soils below raised beds, or just because of gravitational aid to lateral water flow, you'll likely want to use a much heavier soil in raised beds than in containers. More often than not, in raised bed growing we're worried about the flip side of the drainage coin, i.e. retaining water.

Note too, that the PWT height in a tall pot will be the same as in a shallower pot if the same soil is used in both. The advantage is in that: of two containers, equal in volume, the taller will be less likely to be negatively affected by perched water. The reason is because it will have a lower % of saturated soil when soils are at container capacity, and the o/a volume of water in the PWT will be lower, allowing air to return to a higher % of soil, faster.

Al



This is an excellent raised bed soil in its 5th year, very rich and with excellent tilth, it would hold too much water and be inappropriate in containers. Note the Turface (tan, irregularly shaped particles), still maintaining shape & functional integrity after extended, repeat exposure to freeze here in zone 5.


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RE: Container soils and water in containers (cont.)

Once again what you said makes sence. For my raised beds how about 1 part peat 1 part compost 1 part turface? The pwt makes sence, as I learned from reading your thread. So I will make my wood containers taller. My friend with his window boxes might be in all the pwt. His potting soil might have a pwt of 4 or 5 inchs. Thats about how deep his soil is. So like you said the wick is the solution. Thanks Al and justaguy.


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Wed, Jan 3, 07 at 21:07

How about?:

3-5 parts pine bark
1-2 parts peat
1-2 parts compost
1 part turface
1 part sand

Al


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RE: Container soils and water in containers (cont.)

For my raised beds how about 1 part peat 1 part compost 1 part turface?

I can't really say as I haven't played with turface yet. I do like the peat/compost as both are water sponges and the compost provides all the fertility most plants will ever need.

Perhaps one of the others who have used both vermiculite and turface could give an idea of how each would affect the mix positively and negatively.

I would say go ask the question on the veggie garden forum or Sq Ft Gardening forum or a forum more appropriate to raised bed growing, but I doubt too many there have used Turface either so here is probably your best bet.


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RE: Container soils and water in containers (cont.)

I want to use screen at the bottom of my wood containers im making. Does insect screen clog up. Is the mesh too fine? I have some white cedar kicking around. Im going to make a couple 19" deep. I dont want ants or any other insects coming in if I can help it.


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Thu, Jan 4, 07 at 16:40

I use insect screening at the bottom of all my containers (except bonsai) with no clogging problems at all.

Al


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RE: Container soils and water in containers (cont.)

Al and others. I cant thankyou enough. This has been like goimg to school for gardening..Filix


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RE: Container soils and water in containers (cont.)

Thanks so much. I went to the gardening centers 60 miles away today and was only able to get Orchid bark which they said was a mix of fir and hemlock. It says screened. I couldnt find anything called micro nutrient powder and they didnt have it when I asked. I did get perlite and peat as well as Osmicote. Do I leave out the micro nutrient powder or try to order on line? I dont really have access to a good composted manure. I am starting all this with my houseplants first. Oh I also got some granite particles.
Also I think I read this months ago also and saw pictures of the different barks but cant find that now. What is the size of bark again? 1/4 to 1/2 inch?
My husband is a commercial fisherman so I have lots of rope for wicking. Thanks again for all the wonderful information.


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RE: Container soils and water in containers (cont.)

Question. Al do you just put insect screen at the bottom of your wooden containers. OR do you run in up the sides also?...Filix


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Sat, Jan 6, 07 at 21:32

Usually, what I have in wood containers are woody plants that I'm growing on for bonsai. For that reason, the containers are usually shallow & the sides made of a single piece of 1x6 or 1x8, so I only use insect screening on the bottom to keep soil from migrating out the drain holes.

Al


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RE: Container soils and water in containers (cont.)

Al I was wondering if your recipe for woody plants wood be good for my clematis. I built an extra large wood container 28" x 24" x 24". Your mix is one part screened pine or fur bark, one part turface, and one part crushed granite. I thought maybe it would put off a repot for a few years. Would the crushed granite come frome my local sand/stone company? How fine? bb size? And thanks again..Filix


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Thu, Jan 11, 07 at 0:41

It would be an excellent mix as long as you are willing to commit to the frequent watering/fertilizing that it would require.

The crushed granite would "most likely" come from a feed store or elevator - somewhere that sells chicken/turkey feed and the grit that they need in their gizzards to grind the food. Ask for "granite turkey grit". Grani-Grit is the brand I use. It is irregular and sharp and it's o/a mass is close to that of a .177 cal. BB.

Al


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RE: Container soils and water in containers (cont.)

I see, by what I've been scanning, that it's definitely time for this paper to be returned to the top. Maybe someone could re-post it. I don't know what the protocol here is. Nor, for that matter, do I know how. Do we wait till it reaches 150 follow-ups? I know Al won't do it himself, so will someone help?


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RE: Container soils and water in containers (cont.)

Hello from a newcomer

I would like to grow fruit trees and shrubs in containers.
I am afraid that handling large containers for root pruning and repoting can be a hard job, especially getting a plant out of a container.
Would it help to have containers with walls that can be easily screwed / unscrewed?
This question relates to my separately posted msg on the use of fiber cement sheets.
Thanks
FM


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RE: Container soils and water in containers (cont.)

  • Posted by tapla z5b-6a MI (My Page) on
    Tue, Feb 20, 07 at 1:28

I find that if you're careful about the container you use, that plant removal is usually a breeze. I normally only have difficulty removing plants that are root-bound and growing in terra-cotta or unglazed pottery because hair roots will grow right into wall pores. Flexible & nonporous containers offer non of the minute hidey-holes for roots to grow into, so it's easier to extract the planting.

To address your cement board question: Cement board could be very surface porous and might present some potential difficulties in that it could raise media pH substantially unless it was well-weathered. There are many manufacturers of different kinds of cement board, some include water tight laminates on one side, so it's impossible to answer your question with any certainty w/o more information.

Al


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RE: Container soils and water in containers (cont.)

Thank you AI
You are right - cement sheets per se can be quite porous and get soaked with water. However they can be easily coated with a water tight paint. It seems that there is no general answer to the question of alkaline toxicity - one has to experiment and measure pH in the course of practical usage.

By now I have 6-8 month experience of growing in cement sheet raised beds. My pH is around 6.5 with no real difference betwenn the central and peripheral areas of soil.
Vegetable plants (eggplants, capsicums, cucumbers, melons) are doing quite well.
Now I am considering building containers for fruit trees - that's the reason to seek your opinion.

Thanks again
PM, Australia


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RE: Container soils and water in containers (cont.)

  • Posted by bjs496 9/Houston 7/NJ (My Page) on
    Thu, Feb 22, 07 at 13:16

Philoz,

I used Air-Pots last year. I used them only for rooting (which will change this year) but they come in sizes to 120 gallons. One of the nice things about them is they are shipped flat. Therefore, the assembly involves one to wrap the flat sheet and secure it with a "fixing" (in my case its something very similar to what holds the upholstery into your automobile sheet metal.) When it is time to repot/root-prune, you can remove the fixing, and unwrap the container from around your tree in place.

This is necessary because of the design of the container, but it comes in handy for other reasons as well. The overall design of the container is suppose to prevent (or at least minimize) many root problems associated with container growth. I found it to be moderately successful.

I posted on the use of the pots in this forum. I think I just titled it "Air-Pots". I seem to remember a distributor in Australia.

good luck,
~james

Here is a link that might be useful: Caledonian Tree Company.


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