Clay?

[MrFancyPlants]

Does anyone intentionally add clay to their soil mix? I would think a few small chunks mixed in a particulate substrate would help buffer moisture and fertilizer with the high cec. I have also imagined watering with a light clay slurry no thicker than dirty water. I know the frustrations of trying to remove heavy clay soil but wonder if a bit of clay in moderation could be used without clogging and might provide some benefits.

 

[Smoke]

List each of the items you list, clay, fertilizer or CEC and explain what you know about them?


Once you have done that then maybe your questions can be answered.

 

[MrFancyPlants]

Lava - 0 cec. Good drainage/aeration and structure, low water retention

Turface - low cec. Decent drainage, good water retention.

Long sphagnum . Med/high cec?, but may rob nitrogen before it breaks down? Good water retention.

I do have some pumice I ordered, but it hasn't made into much of my mix because it is harder to come by as of yet.

I am also working on some compost, but it won't be ready sooner than next year. If it turns out rich and chunky, I'd probably use that instead of clay, but clay has always intrigued me w it's potential.

 

[Smoke]

Well if I might......

What is clay?

Clay is not a mineral. It is a substance. Clay can be mined from kaolin or it can be made from other substances.

Wikipedia says this about clay.

Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter.[1] Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.

Why does clay have a higer CEC than sand? Clay has a higher CEC than sand because of two things.
1. sand is nearing the last erosian process on its way to becoming clay, but does not contain the organics shown in red above
2. clay contains the organic matter shown in red above.

In a way your previous query into adding clay into your soilmix is a good one but slightly off center. You don't want to add clay to your soil as a an emulsion, you need to add it to the soil mix as a particle. A particle the size of all the other particles you wish to mix together to make the mix.

Keep in mind that there are literally thousands of web sites about CEC and the benifits of clay and humates (organic matter).

Lets talk about clay as a soil ingrediant. This granite rock is clay.

 

[Smoke]

Ok...not the kind of clay one would think as in making a pot out of, but the making or ingrediants of clay.

Rocks are the building blocks of clay. Clay soil is the result of millions of years of erosian and the mixing of organic matter and the settleing out of the substrate into layers with successive layers building on top of it. The richest layers will always be at the bottom while the upper layers will not contain enough organic matter to constitute a good clay soil for our needs.

What is the difference between clay for a pot and clay for soil?

Clay for a pot is mostly man made from crushing silicon bearing stone and associated minerals to create a more plasticine homoginous mixture unsuitable for soil. It contains no organics. In fact clay for ceramic use would in fact be very bad with lage amounts of organics in it die to the formation of gases and hollow voids in the clay during firing.

I hear of people talking about diatomacious earth and oil dry and kitty litter and turface as a substitute for clay since it is fired clay...... right?

Yes it is fired clay, but it is clean fired clay and fired too hard. It is not organic in the first place and even if it was to some extant, the firing process has ruined its ability to have cation exchange due to it now being stone and no longer clay. It is now semi vitreous, (glass like)


Fired clay and earthen clay are not the same thing. The granite rock I showed above has the poorest CEC of all, yet when eroded and turned into a clay substrate with organic matter it becomes wonderful clay. Why? because granite is a mixture of silica crystals, (Quarts) Feldspar, No. one mineral for making throwing clay, along with mica, and dorite. The San Joaquin Valley is literally surrounded by granite. El Capitan in Yosemite is the largest out cropping of granite in the world. Some of the fastest and largest rivers in the US fall from the Sierra Nevada's and have ammased huge quanities of clay into the valley. This millions of years layers of clay along with OM (oganic matter) has left us with a huge deposit of clay in the valley. It is estimated that it could be as deep as one mile thick.

In the San joaquin Valley farmers who work this soil and grow much of the worlds food will "deep rip" to turn the soil to reach the more organic material deeper down. many farmers wil actually remove a foot or more soil to get to a foot deeper in the ground to bring up richer OM laden soil.

 

[Smoke]

Now we have to change the terminology a little to make this work for bonsai.

If I were to make a soil mixture that

drained freely
had a clay component that wasn't fired hard
Had a good cation exchange with organic matter

What would one use?

One might use small balls of clay type soil that would not break down with repeated waterings.

How about this stuff. This is a field in Hollister California the grows artichokes. Who doesn't love artichokes! This field and thousands of acres like it are grown in straight field clay soil.

It looks like this

 

[Smoke]

Those pictures represent a field of clay that has been disked. The particles are varied with sizes from a baseball to the size of a pea. Perfect for soil making. I picked up a few particles in the pea size and tried to crush them. It is not crushable. I have no doubt this stuff would hold up for years in a pot and not break down.

This is not calidama, which is hard pan, this stuff can be smashed it just takes a whack with your foot and it turns to sand. Take a look at the particle in my hand and notice the large amounts of OM in the particle. This is what is needed to have a high CEC.

Ok so how do I get some of this stuff? You can't. Unless you have a friend that has acerage in the San Joaquin valley and is able to send it to you. There is a place that this type of soil can be bought. It is clay earthage, contains OM, and is hard enough to retain its shape with repeated waterings. It is called akadama. Red balls from Japan.

This concludes part one for now.

 

[markyscott]

Well if I might......

What is clay?

Clay is not a mineral. It is a substance. Clay can be mined from kaolin or it can be made from other substances.

Wikipedia says this about clay.

Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter.[1] Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.

Why does clay have a higer CEC than sand? Clay has a higher CEC than sand because of two things.
1. sand is nearing the last erosian process on its way to becoming clay, but does not contain the organics shown in red above
2. clay contains the organic matter shown in red above.

In a way your previous query into adding clay into your soilmix is a good one but slightly off center. You don't want to add clay to your soil as a an emulsion, you need to add it to the soil mix as a particle. A particle the size of all the other particles you wish to mix together to make the mix.

Keep in mind that there are literally thousands of web sites about CEC and the benifits of clay and humates (organic matter).

Lets talk about clay as a soil ingrediant. This granite rock is clay.

One of the confusing elements of the word clay is that it has a number of different meanings. One use of the term refers to a broad group of hydrous aluminosilicate minerals. The term clay, in this usage, means mineral. There is even a Clay Mineral Society. I was a member many years ago. The major groups of clay minerals are the kaolin group, the smectite group, illite and the chlorite group. They differ in terms of their mineralogic structure.

Another use of the term refers to grain size. Any sediment grain less than 2 microns in diameter is referred to as a clay size grain. Generally clay minerals are in this size fraction but other minerals are also (primarily quartz).

The term clay in common usage refers to a sediment that is primarily composed of clay minerals. Organic matter is often found in clay sediment. On average, clay sediment is composed of 1 1/2 weight % total organic carbon, but some clay sediments can be much lower and some can be as high as 30-40 weight % TOC. Different clay minerals have different material properties which is why modeling clay is different than clay used for other purposes.

The CEC of clay sediment is higher than other minerals (although it is much lower than organic material in general) for three reasons. 1). The fine grain size increases the surface area. High surface area increases CEC. 2). Because of their mineralogic structure, clay minerals have charged surfaces. Charged surfaces mean that dissolved ions can adsorb more easily to clay surfaces, so clay minerals have a higher CEC than other similar size particals. 3). Clay sediment has a high CEC because of the common association with organic material.

In terms of akadama, I have seen a bulk rock major element analysis, but have never seen a measurement of the TOC or an XRD analysis indicating what clay mineral it is composed of. Volcanics typically alter into zeolites (another type of clay mineral). I wouldn't be surprised if akadama has some of that given that the manufacturer describes it as altered pumice, but I don't know.

Scott

 

[Anthony]

Marky,

I don't think Akadama is clay, and it doesn't seem to be able to knead and shape as say earthenware clay can. In fact when I fired the Akadama, it just became friable.

The simplest test for clay [ pottery ] is to see if can coil and then be bent around a finger.

I think as fired porous clay [ pottery ] goes, be it earthenware, stone ware or porcelain or even bone china, if it can hold water, it will hold fertiliser in soloution, within itself.
On IBC, there is a guy from Australia, who may be a soil scientist, [ maybe Paul here ] but I think he also mentioned this as well.

So fired porous clay, would work as a reservoir for water and some fertiliser.

The organic part because it is so cec high, one may be able to use in very small quantities.

However does anyone know if there is an optimum cec for trees - say 50, 35 or 75 ....?
You might be able to simply blend a soilless mix to get the answer?
[ soiless, but containing some compost or cured manure ]
Good Morning
Anthony

* where did the fines clogging the drainage hole come from, never seen that happen.
Roots yes, silt no.

 

[markyscott]

...
I don't think Akadama is clay, and it doesn't seem to be able to knead and shape as say earthenware clay can. In fact when I fired the Akadama, it just became friable.

The simplest test for clay [ pottery ] is to see if can coil and then be bent around a finger.

Hence the problem with the term "clay" and the reason for the disambiguation in my last post.

The ability to knead and shape is a property of some clay soils but not a property of all sediments containing clay minerals or clay-size grains. Some sediments containing clay minerals can be quite friable, others can be hard like a rock, and others can flow like toothpaste.

I believe that akadama is probably a partially altered volcanic rock. The pictures I've seen of the mining operation suggest that it is found above a soil horizon in a volcanic deposit. Volcanic rocks typically break down into various clay minerals, including zeolite. I'm a petrologist and I don't know what is the clay mineral content of akadama, but I would not be surprised if it contains a lot, especially if it is within the zone of illuvation. The fact that it is friable when fired means nothing in terms of its clay mineral content.

This is part of the problem with trying to find an "akadama replacement". No one really know what "it" is that we're trying to replace.

Scott

 

[MrFancyPlants]

Quite an interesting read all around. I appreciate the input, and you did catch me on the hunt for the a local akadama replacement, which feels like the search for the fountain of youth sometimes. You are correct to question my knowledge of the definition of clay and point out the infinite flavors of the mineral composition of clay. I guess my point is that although small particles can be bad for a soil, they also can have advantages, and it is really the structure of the soil that is important. Also interesting, in the article that Dario posted about cec and how they ranked cec of clays according to their "darkness" which likely correlates to the organic content.
A few years ago I claimed to have "arrived" horticulturally with the purchase of a couple 50 pound bags of turface. I'll further define my "arrival" by saying that I became reasonably confident that I could keep a potted plant alive for a number of years, and of course, there is always room for improvement, like scoria and/or a yard.
There is always room for improvement. Often when I bring in a subject in to the local club meeting, I'll get the question if I am fertilizing. Of course I am and there are many reason why they might be asking that other than that my my soil's cec is too low, but the hunt continues. The closest I have found is dried vermiculture compost, but my supply has dried up. I will continue to experiment much in the way that my cooking is always an adventure.
Smoke, to answer one of your questions, my step dad, who happens to be visiting doesn't like artichokes, but thanks for the great photos and information. Maybe I'll bring a bucket on my next trip to Cali.

 

[Smoke]

This is what I feel about turface as a soil component.

This represents 500 pounds of the crap I recently poured on the ground of my side yard. I can tell you with confidence that growing in this stuff is a challenge at best. Those that have never experienced what a one third lava, one third pumice, one third akadama soil is are missing the greatist thrill in life.

I understand its disdain from the price to avaiibility to breakdown during the freeze thaw. But for those that can afford it, and those that can get it, and those that do not have to suffer with weather are eating cavier while the rest sample from a jar of salmon eggs.

 

[MrFancyPlants]

I happen to love salmon roe but I get where you are going with that. I was surprised how powdery the pumice that I got is.

 

[Anthony]

Smoke,

I think I saw something about turface being a bentonite type clay that was fired to just what would be called - sinter bonding - about 650 deg.c.
Might break down very fast and if any of the stuff was not heated to 650, it might go back to being very sticky,gummy, but without body.

I spoke to Owen R. about my mix months ago, he suggested if it worked not to change anything.
No problems thus far, and tests are being done to see if there is any difference in the response of a mature tree, with fine branching. For what that is worth.
Good Evening.
Anthony

 

[Smoke]

I happen to love salmon roe but I get where you are going with that. I was surprised how powdery the pumice that I got is.

Well its soft so thats understandable.

 

[davetree]

Every winter I bite the bullet and buy pumice, akadama, and lava and have it shipped to me. The few dollars more I pay means nothing as my trees have grown much better in this type of mix. If you're going to grow a tree worth your time I think it's smart to use top quality soil ingredients.

 

[coh]

Quite an interesting read all around. I appreciate the input, and you did catch me on the hunt for the a local akadama replacement, which feels like the search for the fountain of youth sometimes. You are correct to question my knowledge of the definition of clay and point out the infinite flavors of the mineral composition of clay. I guess my point is that although small particles can be bad for a soil, they also can have advantages, and it is really the structure of the soil that is important. Also interesting, in the article that Dario posted about cec and how they ranked cec of clays according to their "darkness" which likely correlates to the organic content.
A few years ago I claimed to have "arrived" horticulturally with the purchase of a couple 50 pound bags of turface. I'll further define my "arrival" by saying that I became reasonably confident that I could keep a potted plant alive for a number of years, and of course, there is always room for improvement, like scoria and/or a yard.
There is always room for improvement. Often when I bring in a subject in to the local club meeting, I'll get the question if I am fertilizing. Of course I am and there are many reason why they might be asking that other than that my my soil's cec is too low, but the hunt continues. The closest I have found is dried vermiculture compost, but my supply has dried up. I will continue to experiment much in the way that my cooking is always an adventure.
Smoke, to answer one of your questions, my step dad, who happens to be visiting doesn't like artichokes, but thanks for the great photos and information. Maybe I'll bring a bucket on my next trip to Cali.

You may be familiar with Julian Adams (also from Virginia). He grows his bonsai in mostly turface...roughly 70%. Remaining ingredients are mostly granite grit and a little peat. He does pretty well I also know others who use turface as their primary soil component. I'm not saying it's better than smoke's recipe, just different...and it obviously can work.

Personally, I use turface as a component in my "growing out mix" but am moving away from it (toward something more similar to what smoke listed) for the bonsai.

Chris

 

[63pmp]

Don't add clay to your mixes, it won't help.

They is some weird stuff being talked about here, but basically Scott is right on the money.

The problems began when people started talking about clay as a soil component. The important aspect of soils is structure, that is the level of porosity. It doesn't matter too much what the soil is composed of, without structure plants won't grow. Which is probably why they are ripping soil to depth in san joaquin valley. Some clays are better then others in that clays decompose and release nutrients to the soil. Clays derived from basalts are much more fertile then clays derived from granites or from sandstone for that matter.

Now CEC is a double edged sword. CEC from organic matter is basically a myth that hangs around bonsai forums. CEC of organic matter is pH dependent and is greatest at pH greater then 7.5, it diminishes quite quickly below pH 7, which is where we grow bonsai plants.

CEC is also very much related to particle size, and so large particles have very low CEC, even if composed of clay particles. Clay CEC is not pH dependent.

Organic matter is important in clay soils because it binds the clay particles together to form larger particles, called peds. These peds are what give the soil structure and allow air to circulate within the ground.

I think CEC in bonsai potting mixes is over hyped because of the frequency of fertilizing. High CEC components, such as zeolite can have a negative effect as well.


Paul

 

[mat]

You may be familiar with Julian Adams (also from Virginia). He grows his bonsai in mostly turface...roughly 70%. Remaining ingredients are mostly granite grit and a little peat. He does pretty well I also know others who use turface as their primary soil component. I'm not saying it's better than smoke's recipe, just different...and it obviously can work.

Personally, I use turface as a component in my "growing out mix" but am moving away from it (toward something more similar to what smoke listed) for the bonsai.

Chris

Jim Smith is in this category as well. (old school turface user with amazing trees) Many of his masterpieces are in 100% turface, or at least they were 2 or 3 years ago when I asked him about it. This also looked to be the case at many of those on display at Heathcote.

I'm not saying that it's the "best" substrate. But if you're going to go with the "show me your trees as proof" argument, this approach should be pretty convincing - at least for tropicals and subtropicals. As you said, turface can work and produce excellent results.

 

[Anthony]

Paul,

to say thank you and ask, is there any book that explains all this soil technology, so I don't have to keep reading on the Internet?

Read the bit on the topic - Double the fertiliser ......

I think for now I will just stick with what I am doing, as nothing has died for a while, save an old Fukien tea this year [ and that died from a then unknown aphid attack.]

Any thoughts on the efficiency offered by air pots / colanders and the effect caused by roots hitting the air , being stopped and restarting from closer to the trunk, efficiently making use of the soil?
Thanks in advance.
Good Evening.
Anthony