Container Soils - Water Movement and Retention XI

11 years ago

I first posted this thread back in March of 05. Ten times previous, it has reached the maximum number of posts GW allows to a single thread (150), which is much more attention than I ever imagined it would garner. I have reposted it, in no small part, because it has been great fun, and a wonderful catalyst in the forging of new friendships and in increasing my list of acquaintances with similar growing interests. The forum and email exchanges that stem so often from the subject are, in themselves, enough to make me hope the subject continues to pique interest and the exchanges provide helpful information. Most of the motivation for posting this thread again comes from the participantsÂ reinforcement of the idea that some of the information provided in good-spirited collective exchange will make some degree of difference in the level of satisfaction of many readersÂ growing experience.

I'll provide links to some of the previous nine threads and nearly 1,700 posts at the end of what I have written - in case you have interest in reviewing them. Thank you for taking the time to look into this subject - I hope that any/all who read it take at least something interesting and helpful from it. I know it's long; my wish is that you find it worth the read.

Container Soils - Water Movement and Retentionsize>

A Discussion About Soilssize>color>

As container gardeners, our first priority should be to insure the soils we use are adequately aerated for the life of the planting, or in the case of perennial material (trees, shrubs, garden perennials), from repot to repot. Soil aeration/drainage is the most important consideration in any container planting. Soils are the foundation that all container plantings are built on, and aeration is the very cornerstone of that foundation. Since aeration and drainage are inversely linked to soil particle size, it makes good sense to try to find and use soils or primary components with particles larger than peat. Durability and stability of soil components so they contribute to the retention of soil structure for extended periods is also extremely important. Pine and some other types of conifer bark fit the bill nicely, but IÂll talk more about various components later.

What I will write also hits pretty hard against the futility in using a drainage layer of coarse materials as an attempt to improve drainage. It just doesn't work. All it does is reduce the total volume of soil available for root colonization. A wick can be employed to remove water from the saturated layer of soil at the container bottom, but a drainage layer is not effective. A wick can be made to work in reverse of the self-watering pots widely being discussed on this forum now.

Since there are many questions about soils appropriate for use in containers, I'll post basic mix recipes later, in case any would like to try the soil. It will follow the Water Movement information.

Consider this if you will:

Soil fills only a few needs in container culture. Among them are: Anchorage - A place for roots to extend, securing the plant and preventing it from toppling. Nutrient Retention - It must retain enough nutrients in available form to sustain plant systems. Gas Exchange - It must be sufficiently porous to allow air to move through the root system and by-product gasses to escape. Water - It must retain water enough in liquid and/or vapor form to sustain plants between waterings. Most plants can 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 to move 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 container than it is for water at the bottom. 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; in other words, waterÂs 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, and it will stop rising when the GFP equals the capillary attraction of the fibers in the paper.

There will be a naturally occurring "perched water table" (PWT) in containers when soil particulate size is under about .125 (1/8) inch.. This is water that occupies a layer of soil that is always saturated & will not drain from the portion of the pot it occupies. 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 surpass the GFP; therefore, the water does not drain, it is perched. The smaller the size of the particles in a soil, the greater the height of the PWT. This water can be tightly held in heavy (comprised of small particles) soils and ÂperchÂ (think of a bird on a perch) just above the container bottom where it will not drain; or, it can perch in a layer of heavy soil on top of a coarse drainage layer, where it will not drain.

Imagine that we have five cylinders of varying heights, shapes, and diameters, each with drain holes, and we fill them all with the same soil mix, then saturate the soil. The PWT will be exactly the same height in each container. This saturated area of the container is where roots initially seldom penetrate & where root problems frequently begin due to a lack of aeration. Water and nutrient uptake are also compromised by lack of air in the root zone. Keeping in mind the fact that the PWT height is dependent on soil particle size and has nothing to do with height or shape of the container, we can draw the conclusion that: Tall growing containers will always have a higher percentage of unsaturated soil than 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. From this, we could make a good case that taller containers are easier to grow in.

A given volume of large soil particles has less overall surface area when compared 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 height of the PWT is lower in coarse soils than in fine soils. The key to good drainage is size and uniformity of soil particles. Mixing large particles with small is often very ineffective because the smaller particles fit between the large, increasing surface area which increases the capillary attraction and thus the water holding potential. An illustrative question: How much perlite do we need to add to pudding to make it drain well?

We have seen that adding a coarse drainage layer at the container bottom does not improve drainage. It does though, reduce the volume of soil required to fill a container, making the container lighter. When we employ a drainage layer in an attempt to improve drainage, what we are actually doing is moving the level of the PWT higher in the pot. This simply reduces the volume of soil available for roots to colonize. Containers with uniform soil particle size from top of container to bottom will yield better and more uniform drainage and have a lower PWT than containers using the same soil 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 on soil particles for water to be attracted to in the soil above the drainage layer than there is in the drainage layer, so the water perches. 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 employ 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, you can simply insert an absorbent wick into a drainage hole & allow it to extend from the saturated soil in the container to a few inches below the bottom of the pot, or allow it to contact soil below the container where the earth acts as a giant wick and will absorb all or most of the perched water in the container, in most cases. Eliminating the PWT has much the same effect as providing your plants much more soil to grow in, as well as allowing more, much needed air in the root zone.

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/"suffocate" because there is insufficient air at the root zone to insure normal water/nutrient uptake and root function.

Bark fines of fir, hemlock or pine, 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 too quickly break down to a soup-like consistency. Conifer bark also contains suberin, a lipid sometimes referred to as natureÂs preservative. Suberin, more scarce as a presence in sapwood products and hardwood bark, dramatically slows the decomposition of conifer bark-based soils. It contains highly varied hydrocarbon chains and the microorganisms that turn peat to soup have great difficulty cleaving these chains.

To confirm the existence of the PWT and how effective a wick is at removing 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 and allow the water to drain. When drainage has stopped, insert a wick into the drain hole . Take note of how much additional water drains. Even touching the soil with a toothpick through the drain hole will cause substantial additional water to drain. The water that drains is water that occupied the PWT. A greatly simplified explanation of what occurs is: The wick or toothpick "fools" the water into thinking the pot is deeper than it is, so water begins to move downward seeking the "new" bottom of the pot, pulling the rest of the water in the PWT along with it. If there is interest, there are other simple and interesting experiments you can perform to confirm the existence of a PWT in container soils. I can expand later in the thread.

I always remain cognizant of these physical principles whenever I build a soil. I havenÂt used a commercially prepared soil in many years, preferring to build a soil or amend one of my 2 basic mixes to suit individual plantings. I keep many ingredients at the ready for building soils, but the basic building process usually starts with conifer bark and perlite. Sphagnum peat plays a secondary role in my container soils because it breaks down too quickly to suit me, and when it does, it impedes drainage and reduces aeration. Size matters. Partially composted conifer bark fines (pine is easiest to find and least expensive) works best in the following recipes, followed by uncomposted bark in the Note that there is no sand or compost in the soils I use. Sand, as most of you think of it, can improve drainage in some cases, but it reduces aeration by filling valuable macro-pores in soils. Unless sand particle size is fairly uniform and/or larger than about Â½ BB size I leave it out of soils. Compost is too unstable for me to consider using in soils. The small amount of micro-nutrients it supplies can easily be delivered by one or more of a number of chemical or organic sources.

My Basic Soils

5 parts pine bark fines (partially composted fines are best)

1 part sphagnum peat (not reed or sedge peat please)

1-2 parts perlite

garden lime (or gypsum in some cases)

controlled release fertilizer (if preferred)

micro-nutrient powder, other continued source of micro-nutrients, or fertilizer with all nutrients - including minors

Big batch:

2-3 cu ft pine bark fines

5 gallons peat

5 gallons perlite

2 cups dolomitic (garden) lime (or gypsum in some cases)

2 cups CRF (if preferred)

1/2 cup micro-nutrient powder (or other source of the minors - provided in some fertilizers)

Small batch:

3 gallons pine bark

1/2 gallon peat

1/2 gallon perlite

4 tbsp lime (or gypsum in some cases)

1/4 cup CRF (if preferred)

micro-nutrient powder (or other source of the minors)

I have seen advice that some highly organic (practically speaking - almost all container soils are highly organic) container soils are productive for up to 5 years or more. I disagree and will explain why if there is interest. Even if you were to substitute fir bark for pine bark in this recipe (and this recipe will long outlast any peat based soil) you should only expect a maximum of two to three years life before a repot is in order. Usually perennials, including trees (they're perennials too) should be repotted more frequently to insure vigor closer to their genetic potential. If a soil is desired that will retain structure for long periods, we need to look more to inorganic components. Some examples are crushed granite, pea stone, coarse sand (see above - usually no smaller than Â½ BB size in containers, please), Haydite, lava rock (pumice), Turface or Schultz soil conditioner, and others.

For long term (especially woody) plantings and houseplants, I use a superb soil that is extremely durable and structurally sound. The basic mix is equal parts of pine bark, Turface, and crushed granite.

1 part uncomposted screened pine or fir bark (1/8-1/4")

1 part screened Turface

1 part crushed Gran-I-Grit (grower size) or #2 cherrystone

1 Tbsp gypsum per gallon of soil

CRF (if desired)

Source of micro-nutrients or use a fertilizer that contains all essentials

I use 1/8 -1/4 tsp Epsom salts per gallon of fertilizer solution when I fertilize (check your fertilizer - if it is soluble, it is probable it does not contain Ca or Mg.

Thank you for your interest.

If there is interest, you'll find some of the more recent continuations of the thread at the links below:

Posting X

Posting IX

Posting VIII

Posting VII

Posting VI

Posting V

Posting IV

If you were benefited by having read this offering, you might also find this thread about Fertilizing Containerized Plants

helpful, as well.

Featured Answer

c00rdb

11 years ago

last modified: 6 years ago

I am having trouble understanding how you are able to grow in such small depths as an inch of the gritty mix. In my experience it dries very fast (by design), but wouldn't such a small volume dry out in only an hour or two simply by evaporation? I have had success with it but using deep containers seems to work best for me.

Also, would you recommend pure turface for sp. which grow in swamp like or flooded conditions for months of the year? It seems I would need a lot more water retention than the 1:1:1 for this type of planting.

-Greg

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Comments (150)

tapla
Original Author
11 years ago
last modified: 6 years ago
Hi, Kernul. Thank you for being so kind. It really pleases me that you find the potential for improvement in your growing experience.

1/4" is too large to be a good choice for the gritty mix. If you can't find something in the 3/32-3/16 range, you could probably sub screened perlite for the granite. A few people have been able to locate 1/8" pumice or appropriate size silica from masonry supply stores or roofing companies. I know there are companies in FL that sell filtering gravel in various sizes, some of them perfect. I'm fortunate in that I've been making the gritty mix for so long I've developed multiple suppliers for all the ingredients - well, almost. I prefer the pre-screened fir bark I get in CHI, but I do have several suppliers I can count on for pine bark that would work just as well after screening.

I've been helping a dear friend in Fremont with her trees for years, and she generally repots in the spring, though you could easily repot there in the fall after leaves drop.

I THINK you'll find repotting instructions in the link JJ left you. If not, and you still have questions, just ask & I'll do my best to answer.

Whether or not you should bare root entirely depends on the plant. Some plants tolerate it and go plugging along as though nothing happened, and others pout if you disturb to large a % of the root mass. Since I haven't repotted everything you're likely to be growing, it might be a good idea to ask on a plant by plant basis, or go easy until you see how they respond. It's likely though, that I will have repotted close relatives of many plants, so should have a good idea what kind of rootwork they'll tolerate w/o balking.

When I remove soil, I use various tools. I have rakes & root hooks designed to remove soil and straighten out wayward roots. I also make extensive use of a root pick, which you can simulate by sharpening a 1/4 - 5/16" dowel in a pencil sharpener & using it to 'pick' away at the stubborn soil pockets.

Repotting & root pruning just takes a little practice, but it is required if your woody plants are to have the opportunity to grow to their potential within the limiting affects of other cultural influences.

Good luck - I hope your enthusiasm continues to grow!

Al
puglvr1
11 years ago
last modified: 6 years ago
DH and I went out of town and driving home I saw a feed store...of course I had to ask if we can stop by to see if I can find some Crushed granite :o)(seems to be the hardest ingredient for me to find)out of all the ingredients. they did carry one brand and one size only... Crushed Granite by Manna pro...although its quite expensive at $5.50 for 5 lbs...but in a pinch or if you don't need to make a lot this would come in handy, I bought a bag so I have some to use later, wish I could find the bigger bags you guys are finding at much cheaper prices...but we can't be too picky when its slim pickins,lol...!

Al, do you think we still have to sift/strain or rinse this or is it good to go as is? Thanks!!
{{gwi:9103}}
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jojosplants
11 years ago
last modified: 6 years ago
Hi Pug! So good to see you!!
I found the same stuff here, and in the same size and price. :( Manna pro does not make any bigger bag. :(

Mine seems dusty, so I'm going to rinse/sift(insect screen) just to be safe. :)

Like you I will keep it on hand for my small stuff. I'm thinking of using pearlite for the gritty and got 14" terra cottas for my tree's and hope they don't blow over. lol...
JoJo
puglvr1
11 years ago
last modified: 6 years ago
Hi Jojo...Good to see you too!! Thanks for the tip, I think I will go ahead and rinse/sift it too just to be on the safe side. I'm lucky I'm able to get the large bag of the coarse Silica sand for a substitute for granite but will save this bag for my "most favorite" plants :o)

Its a shame they don't sell the large bags of crushed granite in our area...oh well!
jojosplants
11 years ago
last modified: 6 years ago
They don't here either! :( And everyone has chickens here! I used to ! Lol!! or the silica for that matter.
I found some gravel at a sand blasting supplier, but am having transportaion trouble.. Im going to call around for masonry supplies and roofing soon.
I still think he has a sense of humor. ;)
Take care!! Talk to you soon!
JoJo
jojosplants
11 years ago
last modified: 6 years ago
Hi Kernu11
Here's a link where members have posted where they get their supplies, hope it is of some help to you. :)

JoJo
tapla
Original Author
11 years ago
last modified: 6 years ago
Looks good as is, Nance. I usually give it a quick shaking over window screen though, just to get rid of the dust. With such a small volume like you're working with, you could probably rinse it in a strainer. You know I use it for bonsai soil, and I don't even like that little film of slimy dust on the bottom of the container because it is a good place for root rot to start - especially in the small/shallow containers.

Al
puglvr1
11 years ago
last modified: 6 years ago
Thanks Jojo! Good luck with your search, I hope you find some.

Thanks Al! Appreciate it :o)
meyermike_1micha
11 years ago
last modified: 6 years ago
Lolol....You guys are too much...It is like gold if you can find it, especially in that amount ..

I can get the bags in 50lb ones for 13 dollars, not to make you feel bad though....Love you all and you know that..:-)

Pug, congrats, anything you find is a miracle there I guess..I am sure you will use that for your extra special plants!

Hi Jojo.....How aree the plants doing these days? You are both so lucky to still have all that nice warm heat...

Hi Al..:-)

Mike
puglvr1
11 years ago
last modified: 6 years ago
Hi Mike!! You're so right...like striking Gold,lol... Yes, I'm reserving the crushed granite for my special plants, especially plants from my special friends :o)
I'm still in the 90's here...I'm actually looking forward to some low 80's...but its gonna be a few more weeks before I see that on a regular basis :o(

Would send you and Al some of this heat if I could!
demeter_26
11 years ago
last modified: 6 years ago
Hi Al,
I've read many of your threads in this link and they have been extremely educational. I am new to the gardenweb forum. This is my first posting. I live in Southern Florida. I am about to start container growing tomatoes next month. The sixteen seedlings should be container-ready by the end of October. I really need to know in what proper proportion I should mix the components I have. I've gotten different mixing ratios from various people with some ideas but I trust your advice given the amount of knowledge and expertise you have.
Also, are the fertilizing components that I have ok?
I'm using 15 gal. plastic nursery containers(with cages) sitting on 8ft.X 10in X 2in planks of lumber supported underneath by cinder blocks.
The tomatoes are all indeterminate.
These are the soil components I have:
Pine bark fines, peat moss, perlite, vermiculite, composted cow manure, a calcitic and dolomite lime mix, epsom salts,and manganese sulfate.
The slow release fertilizer I have is 5-10-15.
I have a plant hormone/vitamin formula called "Superthrive" which is supposed to give the plants an extra boost and I also have dry kelp seaweed I can make into a tea after rinsing out the salt.
I know if I get the soil and fertilizers right, at least the plant's immune system will be strong enough to fight off most diseases. That will be one large worry behind me and then I can concentrate on watering, pests and other resistant diseases.
Your help would be greatly appreciated.
Jon
tapla
Original Author
11 years ago
last modified: 6 years ago
Hi, Jon. Thank you for the confidence and the kind words - both appreciated.

It would help if you would give some idea of the temps & o/a weather pattern you expect while you'll be tending your tomatoes. It would also be helpful if I had an idea of how 'fine' the PBFs are. Can you post a picture here of share one by email? Some small ratio variation of the 5:1:1 basic mix will probably serve you well, as it has others and as you've probably noticed in your travels.

Bagged manure usually turns out to be a little bit of manure mixed with a lot of black sand or sandy loam; besides, manure doesn't add anything to your soil you can't get elsewhere w/o the impact on drainage/aeration. You won't need the MnSO4, and probably not the vermiculite. The fertilizer is actually unnecessarily high in P and a little low in N, unless it was a typo & it's actually 15-10-15, in which case it would be better.

I've been starting my tomatoes on a 3:1:2 ratio fertilizer until they get some foliage. About when they hit the top of the cages, maybe 3 ft, I reduce the dose so the leaves just stay green & start adding a little Pro-TeKt 0-0-3 to the fertilizer solution when I fertilize. The silicon in the Pro-TeKt also hardens the plants against heat, insects, and disease. If that seems overly complicated, a 2:1:2 ratio fertilizer would be good (if you can find it - I don't know of any) or just a 1:1:1 ratio, like 20-20-20.

I've done some experimenting with the Superthrive, and this is what I found. (scroll down to my post)

Your turn. ;o)

Al
demeter_26
11 years ago
last modified: 6 years ago
Hi Al,
Thank you for your quick response. The pieces of PBF's are equal if not smaller than the size of an eraser at the end of a pencil. The temp. in Oct. and Nov. will be between 70 to 80 degrees.
Is the 5:1:1 basic mix ratio the PBF's - peat - perlite ratio?
I won't use the composted munure, vermiculite and MnSo4 as you suggested. The 5-10-15 was actually a suggested by someone to boost flowering and fruit growth without boosting too much foliage. I could try to return it or do you think it important enough to keep for the tomato-growing program in the future? Could it possibly be used in place of the Pro TeKt0-0-3 since it's high in potassium?
I read your post (thank you for that as well)on Superthrive and I think I'll use it only during the transplanting of the tomatoes to containers.
Over to you Al.
Jon
tapla
Original Author
11 years ago
last modified: 6 years ago
Yes, you understand the ratio correctly. Somewhere around the 5:1:1 ratio of PBFs:peat:perlite should work well in the weather you described. If the particle size of the bark is very consistent, you should probably use an extra part of peat. If particle size is sort of evenly distributed between dust & the size you mentioned, 5:1:1 is good.

You can add some flexibility to your fertilizer by combining it with 30-10-10 or alternating applications of 30-10-10 and your 5-10-15 until your plants have some size, then combine it 2 parts of 5-10-15 with 1 part of 30-10-10. Its difficult to make a case for any fertilizer for container culture that supplies a regular diet with more P than N, even when the goal is to reduce vegetative growth. most greenhouse crops are started on close to 3:1:2 ratios and 'finished' with nitrate fertilizers in a 2:1:2 ratio to inhibit vegetative growth and produce stout, sexually mature plants.

Al
demeter_26
11 years ago
last modified: 6 years ago
Good solution Al. I'll combine the 5-10-15 with the 30-10-10 as you suggested. As far as the amount of calcitic and dolomite lime mix to use for a 15 gal. container...would a cup be enough? and should it always be added as a slurry to the top of the soil? I know it's important for reasons of pH, and for calcium and magnesium content. I want to get the proportion right since it could raise the ph too high for tomatoes. Also I think you wrote in a thread that one should let the mix sit a couple of weeks before planting with it. Also is the kelp seaweed tea a wise choice for the feeding of micro-nutrients? Someone also mentioned a molasses tea for iron, potassium and carbs?
Is there anything to that?
Thank you so much being so clear and precise in your explanations and generous with your time. It's easy to follow your reasoning.
Jon
tapla
Original Author
11 years ago
last modified: 6 years ago
I'm not sure this message will go through, Jon. I wasn't done posting my reply, so don't think I was being short, I'll finish explaining when they get the technical issues resolved.

Al
demeter_26
11 years ago
last modified: 6 years ago
Thank you Al.
No problem, I didn't think you were. I had some problems myself with submitting a response on the forum this evening. I don't even know if this post will get through.
I'll probably check back into the forum first thing tomorrow morning.

Jon
tapla
Original Author
11 years ago
last modified: 6 years ago

I'll try again .... 1 cup of dolomite in 15 gallons is twice what you need. 1/3-1/2 cup is sufficient. How quickly the lime reacts depends on soil moisture and temperature. When it's warm and the soil moist, the lime can finish the reactive phase in only a couple of days.

You can do as you would like with regard to the teas and elixirs. I find them redundant if I'm sure the plants are getting a full compliment of the elements plants normally get from the soil. I use Foliage-Pro 9-3-6 extensively, because it supplies all the essential nutrients in favorable NPK %s and in a favorable ratio to each other. For the last 15 years or so, I'd say my plantings have done very well, but I don't think they've ever been better than they are while using the Foliage-Pro. It works exceptionally well.

If you're supplying elixirs and solutions with unknown ingredients/nutrients in unknown amounts, AND a fertilizer that is supplying all or some of the nutrients, there HAS to be redundancy. Nutrients added to the soil solution that go unused cannot improve nutrition, but they can make it more difficult for water and other nutrients to be absorbed, or even compete with other nutrients so too little of that nutrient is absorbed. This probably isn't a significant negative, the point being that it does no good to oversupply any single nutrient, and if your fertilizer program is all it should be, there is no need to introduce elements that promote the biological life that collapses the soil you were so careful to build. Gardens are distinctly different from containers, which are much closer to hydroponic growing than they are to gardens. Feel free to ask pointed questions.

Hopefully, this will make it through, but I'm copying it before I send, just in case. I learned my lesson when earlier I lost a post I'd spent more than an hour on. :-(

Al
newgen
11 years ago
last modified: 6 years ago
Anybody in southern California able to find the ingredients of Al's 5 1 1 mix? Where did you find them?

Thanks,
kernul1
11 years ago
last modified: 6 years ago
Hi Al,

Thanks so much for the detailed response from my Sep 13th post on the crushed granite and root pruning. I've continued my hunt for crushed granite in San Francisco. After a lot of searching I think I found a solution that may work but wanted to do a final double check with you.

The product is called "Desert Gold" and is sold in the 1/8" size. It is sold from Lyngso in Redwood City CA, a garden material retailer. I called them and they said desert gold was a crushed granite.

Here is a link to the description on their website. Do you think this would work? It sounds like it fits the requirements.

Also just curious, I know you always say 1/8" - 3/16" inch but what is the ideal size in a perfect world?

Thanks!

Bill
tapla
Original Author
11 years ago
last modified: 6 years ago
You're most welcome.

The desert gold material looks great. I wouldn't hesitate to give it a try. Hopefully, there's not a lot of material larger than 3/16.

In a perfect world, the grit particle size would be uniform at about .100 or 1/10". 3/32 - 5/32 is really really good. 3/23 -3/16 is really good. 3/32 - 7/32 is ok. 3/32-1/4 is getting a little large.

Al
kernul1
11 years ago
last modified: 6 years ago
Speaking of which it would seem that you could screen both small and large particles out to get a uniform mix.

I've went ahead and constructed a sifter using aluminum insect screening to get the small particles out. Would you also recommend using a sifter to get the larger particles out? If so what material do you use? In one of the images earlier in the thread (June 16) it looks like you have several different sifters.

Also, just curious but when you are giving measurements are you defining the height, width and depth? I.e. a perfect particle size would be 1/10" high, wide and deep? What about a particle that is 1/10" high and deep but 1/2" wide? It seems that a lot pieces of the bark also fall into this category where they are longer or flatter.

Thanks!

Bill
tapla
Original Author
11 years ago
last modified: 6 years ago
I use hardware cloth of various sizes as the mesh through which I screen soil ingredients. If the particles happen to be inappropriately large, I would screen to remove them. When I describe materials, it would be materials that would fit through screening material of that size.

Al
demeter_26
11 years ago
last modified: 6 years ago
Hi Al
Thank you for your advice on Thu,Sept.16 at 22:41
in response to my post on sept.16 at 17:30.

As far as fertilizers, I would like to experiment with the Foliage-Pro 9-3-6 (since you've had so much success with it)by using it on half the tomato plants and the combination of fertilizers(the 5-10-15 plus the 30-10-10 you suggested I mix) on the other half. By the way, the 5-10-15 is a CRF (controlled release fertilizer). Are Crf's usually mixed in just the upper one inch in a containerized plant?
If I may ask, where's the best price you've found to purchase the Foliage-Pro 9-3-6?
Jon
tapla
Original Author
11 years ago
last modified: 6 years ago
CRFs can be incorporated OR broadcast on the surface, but because temperature has primary influence on release rates, they work better in containers when incorporated. I would try adding 1/2 tbsp or 2 tsp per gallon of soil when you make it, and then fertilize with the 30-10-10 as required to keep the foliage nicely green and see how that goes.

I just bought 2 gallons of FP from a wholesale supplier in a MI city where I was attending a MABA bonsai convention. They're a wholesale outfit & only sell to entities that have established commercial accounts, so I don't know who might have the best price. I paid $36.50/gallon. I used to buy it from Oakhill Gardens in Dundee, IL, an orchid supply house, but the last time I inquired they were out. I think I paid about $30/gal from them when I last bought it, but that was a couple of years ago & you KNOW things aren't getting cheaper! ;o) Good luck - and DO let us know how you fare. .... always interested in hearing of your successes or observations.

Al
wobur
11 years ago
last modified: 6 years ago
Jon,

I just purchased FP 9-3-6 from New Harvest Hydroponics in Calistoga for 17.95 a quart. Since I haven't been able to find it anywhere else I don't know about the price comparison except on line, which is cheaper until you add shipping and then it gets really pricey. Good luck!

Wobur
demeter_26
11 years ago
last modified: 6 years ago
entities that have established commercial accounts>>>>>

Hi Al,
I need your help again. I was inquiring around to find a nursery who carried the foliage pro 9-3-6. No one seemed to carry it locally...only on line. I mentioned to one local nursery that someone(you of course) on the garden forum purchased it for wholesale at an MABA Bonsai convention but that you had to have an established commercial account with them to purchase it. The nursery informed me if I got the name of the company wholesaling FP, that she could try to contact them and purchase it for me, of course with a slight cost increase for her profit.
Al, do you remember the name of the company you bought it from?
Thank you.
Take care.
Jon
demeter_26
11 years ago
last modified: 6 years ago
Al,
I have a question about ph testing kits/meters and soil testing kits. Since you've been at this a way lot longer than I have, which one/s do you recommend or deem reliable and durable for someone who's going to be gardening seriously.
There are so many out there at garden stores and on line. Some are very expensive while less expensive ones have mixed reviews. I trust your opinion.
Jon
tapla
Original Author
11 years ago
last modified: 6 years ago
Jon - it was 'Commerce Corporation' (Formerly Mollema & Son) in Grand Rapids, MI. I buy many hard to find supplies from them. Try Oakhill Gardens, too. They might have resupplied since I last tried them for 9-3-6.

I would ask the pH/soil testing question on the Hydroponics Forum if no one here steps up with an answer. I really don't worry at all about pH, other than to use common sense in my choice of Ca sources and to add some vinegar to my irrigation water (usually in winter - stuff I'm over-wintering indoors under lights) when I see signs of pH induced Fe deficiency. Any testing I've done on soils & such to get an idea of their pH was done using equipment belonging to a botanic garden near me, where I spend a fair amount of time, so I'm not going to be much help. Sorry.

Al
elbereth
11 years ago
last modified: 6 years ago
Hi Al,

I'm trying to make your basic bark mix, but can't find bark sold in my area. I've checked all the big stores I know of in my area, but all they have is bark mulch. Would that work or is it too overprocessed? Is there any any particular type you would recommend? Thanks a lot,

elbereth
tapla
Original Author
11 years ago
last modified: 6 years ago
It's sometimes difficult to find, Elberth; but it's a well-covered topic. You can do a search of this forum - there are several threads that address the issue, at least one of them being on the front forum page as I write.

Good luck.

Al
greenman28 NorCal 7b/8a
11 years ago
last modified: 6 years ago
A Elbereth gilthoniel...!

Howdy, Elbereth, you really need to see the product in your hand to determine whether the
particles are of appropriate size. *Some* bark mulch is acceptable.

Josh
kernul1
11 years ago
last modified: 6 years ago
Hi Al,

So I've done the treasure hunt and have successfully obtained all the ingredients for the Gritty mix (that took a lot of time, research and patience!). I'm ready to move on to the screening stage and had a quick question.

I'm constructing two screens to filter out the large and small particles. For the large particles I'm using a 1/4" screen. For the small particles, this is where I have the question.

I've scoured through the historical threads and it looks like ideally you are trying to get particle sizes in the 1/8" to 1/4" range to achieve a homogenous mix. With this said it would seem that ideally you would use a 1/8" screen for the small particles.

However, it looks like you are recommending using insect screen or even #10 screen (10 screens per square inch) which I believe are both smaller, tighter screens which might result in some small particles (1/16") staying in the overall mix.

So if you were going for the ideal mix would you use a 1/8" screen for the small particles or go with the #10 or insect screen?

Here is previous post of yours on the topic of particle size

"Tapla - 2) When you make the gritty mix, the two ingredients that are closest in size are going to have the most significant impact on drainage and whether or not the soil holds perched water. What works very well for me is usually the equal parts mix with the screened Turface being the smallest of the components, followed by the granite, which I estimate is about 50% larger than the Turface, and then the bark (largest) in 1/8-1/4" size. Most of the bark is concentrated more toward the 1/4" size. I estimate the sizes to be about 1/16-5/32 Turface, 1/8-3/16 grit, 1/8-1/4 bark. I would prefer the Turface was just a fraction larger and the grit a fraction smaller, but that's how it goes. ;o)

No matter which way you head on particle size, you'll be OK in the aeration/drainage dept - as long as you don't get TOO small, and you can always adjust water retention by +/- the Turface and grit. What you DO need to guard against is a size differential so disparate that the materials want to separate."

Thanks in advance. Your advice has been invaluable! I'm excited to start the process of moving 50 containers over to the new mix (over time)!
kernul1
11 years ago
last modified: 6 years ago
Gritty Mix Ingredients: Bay Area, San Francisco, Oakland, San Jose

For those in the bay area (San Francisco, Oakland, San Jose) that are embarking on the quest to source ingredients for the Gritty Mix here is what I have come up with.

Let me preface this with, after much, much searching I have found the easiest way to source the ingredients, no matter where you are, is to call the manufacturer directly of the product you are looking for and ask if any retailers in your area carry it. This works much better than randomly calling the garden/landscape/feed/roofing retailers who will often have no idea what you are talking about. Also you have to be willing to devote some time to this and drive a little.

TURFACE MVP:
- Ewing Landscape & Irrigation Supplies (San Francisco)
- 1618 Jerrold Ave, San Francisco, CA 94124-2135, 415-695-9530
- http://www.ewing1.com/general/ews_locationmap.html?branch=86
- Around $13 per 50 pound bag.

CRUSHED GRANITE
- Lyngso Garden Materials
- 19 Seaport Blvd, Redwood City, CA 94063, 650.364.1730
- http://www.lyngsogarden.com/
- What you want is the "1/8" Desert Gold (which is crushed granite).
- Al has verified that this will work in a previous post.
- Notes, this is a bigger landscaping supply store. You have to bag it yourself out of a big pile but it isn't too hard.
- $5 per bag which is about 100 pounds.
- In Al's notes he refers to this as Gran-I-Grit (grower size) or #2 cherrystone.
- For this product you can either go the chicken feed route (feed & grain stores), the roofing gravel route (roofing suppliers) or the lanscape supply route (crushed granite).

UNCOMPOSTED SCREEN PINE OR FIR BARK (1/8" - 1/4")
- In a prevous post of Al's he talked about how Shasta Forest Products was one of the large manufacturers in our area for fir bark. They sell 3 cu ft bags of fir bark in the perfect size "1/8" - 1/4")
- http://shastabark.com/products.htm
- I called Shasta and they told me Nurseymen's Exchange in half moon bay carried the product.
- Nurseymen's Exhange (2651 North Cabrillo Highway, Half Moon Bay, CA 94019, 650-726-6361)
- http://www.bloomrite.com/
- 3' Orchid Bark (1/8" - 1/4") (Mini)
- Note, Nurseymen's Exhange is a massive complex, when you pull in go up a little and to the right and park in the customer parking section. I think this place is for wholesalers but they did sell me.
- 3 cu feet for $15 each.

For all these places I would definitely call ahead and confirm they have the product in stock. Good luck and happy hunting. You _can_ find all these products, it just takes a little bit of time.
tapla
Original Author
11 years ago
last modified: 6 years ago
Kernul - the ideal mix would have the granite and Turface at .100-.125" (1/10-1/8), and the bark at .125-.167" (1/8-3/16). I screen the Turface through insect screen & use the fines elsewhere. You can get away with a fraction of the particles under .100" (which is approximately where the PWT disappears) if the other 2/3 of the mix is larger than .100". I like the bark a little on the large side to allow for breakdown (in particle size) over the course of 2-3 growth cycles.

Al
kernul1
11 years ago
last modified: 6 years ago
Thanks Al. When I was searching for the crushed granite I ran across "decomposed" granite. Which the question then occured to me, will the crushed granite break down as well over time? It's weird as it is a rock and I don't imagine rocks breaking down that much as they aren't organic but then maybe I'm missing something.

Also will the Turface break down over time?

Thanks!

Bill
tapla
Original Author
11 years ago
last modified: 6 years ago
The reason decomposed granite exfoliates from bedrock is its high % of mica. As the mica absorbs moisture, it swells and 'blows' flakes of granite from the face of the rock. You won't have this issue to deal with when using Gran-I-Grit or cherrystone. Both granite and Turface are very stable. I used a fraction of Turface in my raised beds for bringing potential bonsai along when I built the soil more than 10 years ago, and I don't see any evidence it's breaking down - even after going through a number of MI winters.

Al
demeter_26
11 years ago
last modified: 6 years ago
Hi Al,
I've been away from the forum for a couple weeks for computer repairs.
Happy to say I finally have some Foliage Pro 9-3-6 and
Pro T-Kt which I hopefully will be using on my tomatoes after they are set into 15 gal. containers. The 5-1-1 mix with dolomite lime is prepared and I'm letting it marinate until planting. I am concerned though that the 20 tomato seedlings in starter containers have stopped growing >>> some at 3 inches while others at just one inch. They're not showing any sign of growth. I kept from over-watering or under-watering. Out of concern, I recently wet the top of the soil for each seedling with the diluted
Foliage Pro 9-3-6 a couple of times hoping to remedy the situation, but no change.
Maybe you could help shine a light on this issue, Al?
I would greatly appreciate it.
Jon
tapla
Original Author
11 years ago
last modified: 6 years ago
One of the first indicators of tight roots is stalled extension of branches/stems and weak growth; but I'm guessing, at 3" tall that's the not the issue. If you haven't fertilized previously, there is no reason you can't give the seedlings a full recommended strength dose of fertilizer. If you make sure they are getting good light (read full sun) and are warm enough - they should take right off. BTW - what kind of medium are they in now? ... keeping it damp, and not wet?

Al
demeter_26
11 years ago
last modified: 6 years ago
Hi Al,
I have the tomato seedlings in large dixie cups with holes for drainage and they are in the 5-1-1 mix...no dolomite yet. I have gave them a few doses of the pro 9-3-6 fertilzer over a period of 2 weeks when I saw no growth happening. There should have been enough of everything in the fertilizer to get them to a decent height of 6 inches before transplanting, but that's not the case so far.
I'm perplexed. Thank you Al for following up on this issue with me.
Jon
landperson
10 years ago
last modified: 6 years ago
Kernul1, this is Santa Rosa CA checking in. I have called all around here and can't find either the Turface or the Crushed Granite, so I just may have to drive south and go to the places you mentioned. (I CAN find fir bark...whew).

Anyway, I just want to verify that you picked up and found both of those products as useful as you thought they were going to be before I trek 50+ miles for them....

Thanks
Susan
landperson
10 years ago
last modified: 6 years ago
It's me again, Krnul1, and I did just find a source of the Turface here in Santa Rosa. Cool beans !!!!!

If I found that I will definitely find the crushed granite. I just know it !!!!

Back to my research !!!

Susan
kernul1
10 years ago
last modified: 6 years ago
Hey Susan,

Glad to hear you are getting closer to finding all three. I think you can find them all if you look hard enough. If not a little drive should get you there.

I'm happy with all the products I have sourced so far.

Good luck!

Kernul
kernul1
10 years ago
last modified: 6 years ago
Hi Al,

With all the ingredients in hand, I've started the sifting process and had a few questions. I'm trying to swap out 50 containers worth of soil so I'd prefer to do this in the most efficient way.

I am using a 9x9 hardware cloth (.088" openings) to filter the fines. Here are the three ingredients I was able to source:

1) Shasta: Orchid Fir Bark: (1/8" - 1/4")
http://shastabark.com/products.htm

2) Turface MVP

3) 1/8" Crushed Granite (Desert Gold)
http://www.lyngsogarden.com/index.cfm?event=Display.Home.Product.Group&homeCategory=STONE&categoryid=1094&productgroup=PEBCOB&groupname=Pebbles%252C%2520Cobbles%2520%2526%2520%2520Colored%2520Gravel

Questions:
1) It seems like it takes a decent amount of time to screen out the fines for one container. I also have constructed two other screens to be used to filter out the larger particles (a 1/4" for the large fir bark and a 9x9 (.1387") for the larger turface/granite).

I'm assuming that at the end of the day it is more important to screen out the fines then to screen out the few larger pieces which may be in the mix. Would this be correct? I'm just trying to save some time and there doesn't seem to be that many larger pieces in the mixes.

2) Do you usually rinse out the mixes before you combine them? Does this help get additional dust/fines out?

3) What do you do with all the fines/dust that you sift out? If you are screening out larger pieces what do you with them?

Thanks so much in advance. Your advice and guidance have been invaluable.

Best,

Kernul1
tapla
Original Author
10 years ago
last modified: 6 years ago
I would screen everything over the .088 and call it good - unless there is a wide size disparity in the granite (the 2 products I use are screened so the size is very uniform). Screening the bark and granite is just to remove the dust, while screening the Turface removes what would be too high a % of fines.

I don't often rinse, but it would remove additional dust. The reason I don't is because I usually make large batches & I don't want a wet screen or to clog my screen with dust mud as I move to the next batch.

I toss bark fines on the gardens/beds and use the fines from Turface in my raised beds or in hypertufa projects in place of sand. I don't get enough dust from the granite to even think about - it just settles on the lawn where I do my screening.

Al
jodik_gw
10 years ago
last modified: 6 years ago
Well... here we are, coming to the end of yet another "Container Soils - Water Movement and Retention" thread... the next will be number 11, I believe! Wow! When I first read this article, I believe we were at or around number 7.

This has proved to be a very popular thread with a very important article! For me, it's the base of where it all begins for container grown plants. It's the "why" and the "how" explained so simple and beautifully. It's the beginning of my success as a container gardener, and I'm certain I'm not the only one!

I not only look forward to many more new articles and information from Al, but I also look forward to seeing this one carried forward to number 11... and 12... and so on!

Congratulations, Al, on your continued success as a knowledgeable and popular teacher!

I remain your humble student, and your good friend. :-)
jojosplants
10 years ago
last modified: 6 years ago
LOL!
I was thinking the same things. ;)
JoJo
tapla
Original Author
10 years ago
last modified: 6 years ago
Thank you so much, guys!! It might take a couple of posts for me to finish off this thread, but please follow the link below to the continuation;

THANK YOU ALL SO MUCH FOR MAKING IT FUN AND KEEPING IT FRIENDLY!

Al
tapla
Original Author
10 years ago
last modified: 6 years ago
Continue discussion by following link below.
tapla
Original Author
10 years ago
last modified: 6 years ago
It's supposed to end at 150. This is 151. ;o)

Al

Container Soils - Water Movement and Retention XI

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