Soil DOE - Beating a dead horse!

[macdad]

Honest I have used Play Marbles, Aquarium gravel, Deco art stone, and many more items to long to list. All seem to work ok as long as they get water and nutrients. I am almost done making everything the same though as it is easier to keep track of. For me it is Dry Stall(pumice) 2/3 and Traction grit 1/3 for all. In Spring some of the new additions will get the same with some Pine Horse Bedding like Wisteria, Willows, Abriels, and Burning Bush. They have a different Nitrogen need as well as Bougies. Prior to that everything else will get the same and those new additions will be in a different water and fertilizer zone bit all the same as well.

Grimmy

Grimmy, with what little experience I have this summer, I am leaning towards the same basic principle. We recently had several very rainy days, and I had to move my trees to cover in fear of them drowning.

Interesting thread. I am especially pleased by the effort to collect data and analyze it instead of relying on anecdotes. Thanks!!

It is well known that tree roots need to have at least a 12% pore space in addition to some free water.

I would measure this by carefully measuring volumes and not weights. I would place a carefully measured volume of the experimental mix into the cups before watering (keeping this volume at some consistent amount less than a full cup). I would measure an amount of water, just less than a full Dixie cup, with a kitchen measuring cup (a graduated cylinder would be better if you have one). Then I would nest a perforated cup inside a another cup with no holes, pour in the known amount of water (which should 'drown' the mix), and then lift up the perforated cup of mix, letting all the water drip into the unperforated cup. After water quits flowing from the perforated cup, I would measure the amount of water in the unperforated cup. Clearly the missing water (water poured in minus water volume recovered) is in the mix.

fractional pore space filled = water volume 'lost' / mix volume

I think this is a better response metric than weight (though I suppose it could be problematic with organics that 'puff up' when wetted)


BTW, since you are an engineer, you might want to read this paper on soil water potential and maybe some others before you decide what to do next.

Thanks for the link. I will definitely read it. Also, I didn't do that exact technique, but I did something very similar. Basically, I used a volume of water equal to the volume of soil mix on the initial wetting. Approximately 18 oz. I calculated the weight (in grams) of 18 oz of water. I weighed the cups after initial wetting to determine the water weight, then divided the water weight in the soil by the total water weight.



I should do this again more precisely though. I measured the volume of soil precisely, but not the volume of water. It was eye-balled.

I also agree with the data vs. anecdotal statement. That was a big reason for the study. Too many times, someone posts anecdotal results and a naysayer (sp?) says it will never work. Regardless of the results, I really wanted to share them.

 

[Anthony]

Probably too simplistic for you guys, but,

plants prefer pots at 6" or less for living in.

All the soil tests done, mean nothing if you are not growing something in it.

Experience has shown that even with our bucket a drop, tropical down pours, 5 mm inorganic sized particles, will support life well, and some compost.

With heavy rains, the concern is how much soil will be beaten out of the pot, not drowning, simply because of the time when repotting and the time when the rains arrive.

I am sure you science guys can factor in those properties for your area, humid or not.

If the very old lady [ 87 ] who attends the meetings can figure out her soil mix, and grow her plants in old tin cups, you guys can as well. She has trees that are over 50 years old, not started as Bonsai, just because she likes to grow things.
Good Day
Anthony

* I do appreciate the charts by the way.

 

[macdad]

Thanks Anthony! Like many others, I really like to over-complicate things. Bottom line, this is how I learn. It is another reason that I choose hobbies or past times. It gives me something to experiment with, learn from, and or fix.

I really like your comment of the 87 year old woman. There is a lot of truth in that.

 

[0soyoung]

plants prefer pots at 6" or less for living in.

Anthony,

You raise a good point; specifically, these tests ought to be done with clear cups!

There will always be a layer of soil with no air-space at the bottom of a pot after the mix has been watered. This 'saturation layer' has no air space. The thickness/height of this saturation layer should be recorded as it is an important property of the mix (and this thickness/height is well known to be independent of the shape of the container).

Suppose we have two mixes that retain the same amount of water, but one has a lower saturation level. Since roots 'drown' when they are underwater we might consider the mix with a lower saturation level to be superior because more of the watered soil volume is aerated.

 

[Poink88]

Anthony,

You raise a good point; specifically, these tests ought to be done with clear cups!

There will always be a layer of soil with no air-space at the bottom of a pot after the mix has been watered. This 'saturation layer' has no air space. The thickness/height of this saturation layer should be recorded as it is an important property of the mix (and this thickness/height is well known to be independent of the shape of the container).

Suppose we have two mixes that retain the same amount of water, but one has a lower saturation level. Since roots 'drown' when they are underwater we might consider the mix with a lower saturation level to be superior because more of the watered soil volume is aerated.

Thus, we go back to drain layer, water table, etc.

We need a holistic approach if we really want to understand how this (pot) ecosystem works.

 

[Anthony]

Macdad,

thanks for your patience with my world.

I hope you survive the design part. chuckle. All those angles to compute.
K.I.S.S.[ keep it simple soldier ]
Good Day
Anthony

 

[0soyoung]

Thus, we go back to drain layer, water table, etc.

We need a holistic approach if we really want to understand how this (pot) ecosystem works.

Drain layers really don't drain. There will be the same thickness saturation layer in the mix atop the drain layer. The 'drain layer' usually being larger grained has a thinner saturation layer than the mix. So the saturation layer of the mix is just relocated higher in the pot - it isn't 'drained'. But, it does mean that there is a better growth environment for the roots on the bottom of the root pad than when there is no 'drain layer'. It is an easy thing to demonstrate if you've got the components and a clear container (with holes in the bottom, of course).

I agree that soil/mix properties are complex and that it is difficult to determine the appropriate metrics to measure. The objective, of course, is to grow trees and that is the 'proof of the pudding'. But I think one possible question this experiment is trying to answer what mix ought to be used given the components one has readily available. Aternatively, one has chosen something and then a component ceases to be available - what should be chosen to get a mix with the same water retention properties? And still futher, one might like to understand why people in 'area X' of the world seem to think this mix is the best stuff there is, but my trees do very poorly in it.

I presume by 'holistic approach' you mean grow trees and see what happens. McDad has demonstrated an experimental structure that anyone could use to grow their trees in - it just takes more than one tree in one pot of some mix.

 

[Poink88]

Drain layers really don't drain. There will be the same thickness saturation layer in the mix atop the drain layer. The 'drain layer' usually being larger grained has a thinner saturation layer than the mix. So the saturation layer of the mix is just relocated higher in the pot - it isn't 'drained'. But, it does mean that there is a better growth environment for the roots on the bottom of the root pad than when there is no 'drain layer'. It is an easy thing to demonstrate if you've got the components and a clear container (with holes in the bottom, of course).

Sorry but I disagree.

 

[0soyoung]

Sorry but I disagree.

Got any data to support your beliefs? I'm very interested.

 

[Poink88]

There will always be a layer of soil with no air-space at the bottom of a pot after the mix has been watered. This 'saturation layer' has no air space. The thickness/height of this saturation layer should be recorded as it is an important property of the mix (and this thickness/height is well known to be independent of the shape of the container).

Drain layers really don't drain. There will be the same thickness saturation layer in the mix atop the drain layer. The 'drain layer' usually being larger grained has a thinner saturation layer than the mix. So the saturation layer of the mix is just relocated higher in the pot - it isn't 'drained'. But, it does mean that there is a better growth environment for the roots on the bottom of the root pad than when there is no 'drain layer'. It is an easy thing to demonstrate if you've got the components and a clear container (with holes in the bottom, of course).

The lower drain layer will wick out excess water from the higher saturation layer...letting precious air in sooner than without it. The drain layer also will maintain more aerated space than the regular mix.

Mind you I do not do or use it (almost not needed here in TX) but I understand the concept. I've taken a few soil mechanics & hydraulics class decades ago.

 

[0soyoung]

The lower drain layer will wick out excess water from the higher saturation layer...letting precious air in sooner than without it. The drain layer also will maintain more aerated space than the regular mix.

Mind you I do not do or use it (almost not needed here in TX) but I understand the concept. I've taken a few soil mechanics & hydraulics class decades ago.

I don't use a drainage layer either and I live in a cool damp climate. The idea of 'wicking' literally must come from actually sticking a wick into the bottom of the pot. It, indeed, will 'suck' out water out, but it does this by capillary action and evaporation from the wicking outside the pot. The key point is that the wick has narrower spaces than the mix in the bottom of the pot - more capillary force.

Let us try to think this thru by using simple every day physics to understand how things must work. The only physics or 'science' (which seems to be a bad word) involved is

1. Capillary action
   • a column of water can be supported against gravity in a narrow tube
   • the narrower the tube, the higher the column can be
2. Siphons
   • gravity will pull water through a hose, as long as the outlet end of the hose is lower than the inlet - it doesn't matter where the hose goes inbetween
   • poking a hole in the hose will 'break the siphon', stopping the flow

To begin let's say that when one waters, the whole container is filled with water. When we let it drain, water drains from the bottom of the pot, driven by gravity. The water level will fall until it nears the saturation level of the small grain upper layer where upon capillary action in the slows the water flow. At this point, the 'drain' layer beneith is still saturated with water that cannot be retained against gravity.

At this point two conjectures appear to be possible. One is that the water flow stops when the saturation level of the smaller particle upper layer is reached. But to do this the capillary force in the upper layer must be sufficient to hold the column of water in the drainage layer. But, the saturation layer is when there is a balance between gravity and capillary force in the spaces between the grains - the upper layer cannot hold water against the added force below.

Thus, the second conjecture might be that the water continues to drain because the drainage layer cannot support that high a column of water either, so the drain layer will 'siphon out' the water from the small particle layer above. And it would if there were not inherenty defects in the seal (like the interface with the pot walls and irregularies in the mix) that will admit air to the drainage layer beneath and break the siphon.

So, I think it is clear that we must end with a saturation zone at the bottom of each soil layer. It requires some very special conditions not to (specifically an effective seal to sustain siphoning effects).

Further, from this line of reasoning, I think it is clear that a means of attacking Smoke's problem of growing trees in Death Valley 2 could be addressed by a high moisture retention top dressing. The top dressing would hold water for evaporation, certainly for as long as it has a saturated zone, and would afford an otherwise pot full of loose, well aerated, unsaturated mix, for the tree roots to grow in, below.

 

[0soyoung]

Anthony,

You raise a good point; specifically, these tests ought to be done with clear cups!

Clear cups might not be such a panacea. I just tossed some Turface MVP and small grained Turface ProLeague into 3 clear orchid pots that I have on hand. Surprise! I found it difficult to discern the saturation level and impossible to capture in a photograph. While it might not be impossible, I am now not so sure that clear cups are going to bring much of anything to the party, MacDad.

... never mind ...

 

[GrimLore]

The correct tree care practice:
Copyright 2001 by the International Society of
Arboriculture.Reprinted with permission. 50% 50% mineral water organic matter air SolidsPore Space
•
An ideal soil is made up of 50 percent pore spaces and 50 percent solid particles.
•
Changing the grade by removing soil exposes the roots, and adding lots of soil smothers the roots.
•
Adding as little as 3-4 inches of soil can kill a tree.
•
Compaction decreases the pore spaces’ ability to hold water and oxygen for the roots.

Sorry - had to toss that in

Grimmy

 

[Poink88]

Very nice "technical sounding" post Osoyoung...but full of holes.

Better research more about wicking action, couple that with water column...it is that simple. . Plants have been growing in pots for eons in potting soil even plain dirt and clay (oh no! )...making it so technical and sound almost impossible to grow plants in them is laughable. LOL

 

[Smoke]

I
Further, from this line of reasoning, I think it is clear that a means of attacking Smoke's problem of growing trees in Death Valley 2 could be addressed by a high moisture retention top dressing.

I have absolutly no problem with moisture retension where I live. I simply use a product that has been used for almost a century with measured results and is foolproof. I can afford it, it is readily available, and it holds moisture for days as vapor and not as root killing liquid water held there by small particled sand and capillary action.

AKADAMA!

Please do the tests with this product and then show us what you get. Untill the tests are conducted with that product, what you get in the way of results are moot. It seems that all these experiments are meant to find a product with akadamas attributes and readily available cheaply. Sometimes the Grand Canyon is just a canyon.

 

[Anthony]

Al,

when we started in Bonsai some 33 years ago. We had no akadama, we made do with crushed sifted earthenware brick, compost and builders sharp sand sifted.

To date no problems.

Curiosity with test plants and other materials, show similar results.

So now we are looking to see if there is any difference with density of branchlets.
Akadama, akadama, akadama.
Good Day
Anthony

 

[Smoke]

Al,

when we started in Bonsai some 33 years ago. We had no akadama, we made do with crushed sifted earthenware brick, compost and builders sharp sand sifted.

To date no problems.

Curiosity with test plants and other materials, show similar results.

So now we are looking to see if there is any difference with density of branchlets.
Akadama, akadama, akadama.
Good Day
Anthony

I have had absolutley no interest in this thread. It was not until someone assumed I have a moisture retention problem that I responded. People can use whatever they want and can grow their trees in styrofoam beads and broken glass shards if they so desire. I am satisfied with what I use. I suppose you are happy with what you use. Testing is of absolutly no use because of all the many varibles in use when making soil.

Use what you can find and make it work for the plants benifit. Man must adjust for the needs of the plant. Seems simple.

 

[macdad]

Very nice "technical sounding" post Osoyoung...but full of holes.

No pun intended, I'm sure

I have absolutly no problem with moisture retension where I live. I simply use a product that has been used for almost a century with measured results and is foolproof. I can afford it, it is readily available, and it holds moisture for days as vapor and not as root killing liquid water held there by small particled sand and capillary action.

AKADAMA!

Please do the tests with this product and then show us what you get. Untill the tests are conducted with that product, what you get in the way of results are moot. It seems that all these experiments are meant to find a product with akadamas attributes and readily available cheaply. Sometimes the Grand Canyon is just a canyon.

I will save up my money, so I can buy some next spring. If the government is running by then, I will buy some with my tax return

Honestly, I have no problem testing with this to see what it results, but, in the long run, I will not use this material.

I have had absolutley no interest in this thread.

Thanks for posting in spite of your disinterest! It is always good to have others weigh in.

Use what you can find and make it work for the plants benifit. Man must adjust for the needs of the plant. Seems simple.

That is essentially the reason for my study. I really just wanted to get some information to get me going in the right direction. I am sure my formula will change as my knowledge/understanding of Bonsai grows. Like I said previously, I learn a lot through experimentation and observation. It forces me to think more deeply about the matter.

 

[Smoke]

Originally Posted by Smoke

I have had absolutley no interest in this thread.

Thanks for posting in spite of your disinterest! It is always good to have others weigh in.

The understatement of the year. You have no idea on how many times I have posted in soil threads. Continually since 1997. I don't fight it anymore. Its just not worth the time. There will always be someone new that brings the whole issue up again because the archive button was never used.

I have written about this before in my sixth book: "Cut Paste, Your Nose and Sanding Dust."

 

[GrimLore]

Cut paste - geesh I was almost in tears laughing

Grimmy