Define Your Perfect Soil!

We apparently hijacked the thread on Growing Boxes and turned it into a discussion on soil and fluid mechanics.

Personally, I'm fascinated with the concept and would love to discover what the experts and the newbies have to say on the subject. Hence, the creation of this thread.

Soooo...

I figure I'll kick off the discussion. While I certanly have no problem with critiques of my soil, I think I would really like to know what you are using, how you apply it and maybe even a history of how you arrived at that combination.

My potting mix:

I started off by using way too much "commercial potting soil",; that, and the concern that I wasn't watering "enough", is probably why I killed a lot of trees at first.

My budget really doesn't accomodate the use of high priced, imported mixes or ingredients so I'm mostly improvising. present I only use three ingredients 1. Course sand (although I am moving towards replacing the sand with agricultural granite grit), 2. Baked clay (again, no budget for Akadama) I use a straight clay auto shop absorbant sold by O'Reilly's Auto Parts in the US, and 3. Pine bark mulch.

I'm unsure about the color changes in the soil as presented in the pots. The sand gives the soil a brownish tint, which is what I became used to. The grit, on the other hand, gives the mix a gray to black tint, which is taking some time to get used to.

I mix the clay and grit 50/50 and use the pine bark to adjust the waer carrying capacity of the soil and in a minor part the pH. (More pine bark more acidic). The stand mix would be equal parts at 1/3 each.

I was still tend to screen the sand or grit and save the fines for later use. I do not screen the clay. I find it just grinds it off the clay particles and I do not screen the pine.

I need to add that the soil I use remains subject to change should I find improved ingredients, so I will be following, what others use closely.

Photos can be added if readers would like to compare.

That's my soil,

Jay

That sounds wonderful. The only thing I will add is that soil type, water schedule, container size and shape, root activity and tree transporation are all related and should be understood how they all play together.

Ciao.......Leonardo

Please note: Jay & I are both in Zone 5, USA, & we grow both indoor & outdoor plants. So it is not surprising that our soil mixes are similar.
Our growing conditions have very little to do with California, Puerto Rico, Florida, or Indonesia, and may not be very similar to Europe, so our soil may be different from these regions.
For the gravel component, I used to use fine aquarium gravel, which is silica, but this grade has been almost completely discontinued. Nowadays, I use chicken grit (aka starter grit), which in the Northeast, is commonly crushed granite. For my coarse mix, aka bottom soil or conifer mix, I use turkey grit (grower grit) or the present grade of aquarium gravel, which is quite coarse. Don't use saltwater aquarium gravel; I think that may be limestone.
For the baked clay component, I use Turface or something similar. One of our members got a load of it very cheap. Only thing, it's pink! I have learned to use less than one third of it. We sometimes get a lot of rain in the summer, & the tropicals grow under lights in the winter, so I need very free drainage.
For the equivalent component in my coarse mix, I use Haydite, called Norlite in upstate NY. It is expanded shale.
I also use pine bark mulch. I had a lot of trouble finding something coarse enough. The finely ground pine bark that is usually available sinks to the bottom of the pot & causes root rot. For my coarse mix, I use fine orchid fir bark. The ideal solution for regular mix would be to find someone with a shredder-chipper, & run a bag of fir bark through it.
I add about 10% or so charcoal, which improves the color as well as the texture of the mix.
I can't sift the ingredients, so I wash everything as thoroughly as possible in a colander or strainer. I think this is very important.
My final ingredient is acrylamide crystals, quantity according to the instructions on the jar. I know this is controversial, but some trees, like willow & crabapple, really need it, & if you have good drainage, it should do no harm.
Iris

Our growing conditions have very little to do with California, Puerto Rico, Florida, or Indonesia, and may not be very similar to Europe, so our soil may be different from these regions.

Mine too. Which is why all these soil discussions on bonsai forums are so pointless -- we ALL have widely differing conditions -- which is all I'm gonna say here.

Leonardo,

Please take the time to explain your comments so that others reading can learn from you r experiences about how all these items interact.

Jim,

There might actually be someone out there in your area lurking in the forum as a visitor that might find the answers to soil questions that are nagging them. Either that or they might find out that substitutions you use might work for them.

Iris,

Are the acrylamide crystals the expanding water crystals that turn to gel when hydrated? If so, I have used them for house plants, but you have to be careful not to use too much. If prehydrated and then added to the mix, if allowed to dry out can cause your soil to cave in. If added as crystals they can cause your soil to heave.

Jay

Jay Gaydosh wrote:
Iris,
Are the acrylamide crystals the expanding water crystals that turn to gel when hydrated?

Yes.

Jay Gaydosh wrote:
If added as crystals they can cause your soil to heave.
Jay

I haven't had that problem. Actually, I try to add a little less than it says. Any crystals in the top layer of soil "float" to the surface when it rains, & I discard them. I estimate that the crystals, fully hydrated, add about 10% to the soil volume, so I try to allow for it. Not rocket science.
Iris

Test one. Take a pond basket or any container with proper dainage (100 % bottom drainage with holes in proper position and no 'puddling' on container bottom). Fill the container with eigth inch size soilless mix. It can be granite, lava, pulverized brick ect but it must be clean and sifted graded out to the proper size. Fill the basket with material and dampen slightly to saturate medium used. Set the basket down so it is parallel with the horizon or level. Measure 6 oz. of water and pour into container. Let sit for a few minutes so gravity water drains out. Measure the captured water without disturbing the container. Now tilt the container on a 45 degree angle and measure the amount of water that remained in test container. You will be suprised.

Ciao.....Leonardo

Your point being?
Iris

Nobody is asking you to do anything Iris, this is a voluntary test for those that want to learn, kind of like Biology Lab.....remember those days?

Ciao.....Leonardo

leonardo wrote:Test one. Take a pond basket or any container with proper dainage (100 % bottom drainage with holes in proper position and no 'puddling' on container bottom). Fill the container with eigth inch size soilless mix. It can be granite, lava, pulverized brick ect but it must be clean and sifted graded out to the proper size. Fill the basket with material and dampen slightly to saturate medium used. Set the basket down so it is parallel with the horizon or level. Measure 6 oz. of water and pour into container. Let sit for a few minutes so gravity water drains out. Measure the captured water without disturbing the container. Now tilt the container on a 45 degree angle and measure the amount of water that remained in test container. You will be suprised.

Ciao.....Leonardo

Ok, now we're getting somewhere.

As in any scientific experiment there needs to be some rules. You start with a hypothesis, develop and execute the test, record the results. Analyze the data. And finally, prove, disprove or modify your hypothesis. Added into the mix should be control factors to compare your test results to in order to validate your test. In addition, tests conducted that cannot be duplicated are for the most part useless..

With that in mind, please explain the above test. What is the purpose, what are you attempting to prove, what value do the results hold for the bonsai enthusiast? What controls do you use to help isolate the effects achieved.

If you use a plastic mesh bucket, there will be some water settle to the bottom of the bucket and not drain out. If you use a course sand, rock or other inert material to prevent you mix from dropping out of the bucket and the bucket is deep enough to allow for modest root growth, will the water ever become available to the tree, will it cause the soil above to remain wetter, will it slow down the need to rewater or effect the evaporation, percolation or transpiration of water from the entire unit? Will there be sufficient water to effect the possibility of root rot, breakdown of the organic material or of the baked clay.

These are all (however not all inclusive) questions that could or should be answered with the quoted scenario in order for it to be of value to the reader. In addition, it should be presented in a form that allows those unfamiliar with the subject a modest understanding of what was undertaken when they are through reading it.

Jay

Jay Gaydosh wrote:We apparently hijacked the thread on Growing Boxes and turned it into a discussion on soil and fluid mechanics.

Personally, I'm fascinated with the concept and would love to discover what the experts and the newbies have to say on the subject. Hence, the creation of this thread

Jay

Wow Jay.....I am reading something here about someone that is interested in soil and fluid mechanics. I am giving you more information then I got when I first tried solving this occurrence. There is a belief out there that when soilless plant media is watered, the water will travel through the media and proceed out the bottom of the container being pulled by gravity with little if none left behind in soil pores and spaces.
Well this is not true. There is a zone at the bottom of the container that does not drain and will remain saturated until something removes it. Is this fluid mechanics?

Ciao......Leonardo

I have also seen this in action...I place a larger particle on the bottoms of my pots because of this..
Irene

leonardo wrote:Wow Jay.....I am reading something here about someone that is interested in soil and fluid mechanics. I am giving you more information then I got when I first tried solving this occurrence. There is a belief out there that when soilless plant media is watered, the water will travel through the media and proceed out the bottom of the container being pulled by gravity with little if none left behind in soil pores and spaces.
Well this is not true. There is a zone at the bottom of the container that does not drain and will remain saturated until something removes it. Is this fluid mechanics?

Ciao......Leonardo

Actually, fluid mechanics involves the entire picture of how the water (in this situation) interacts with the entire environment it encounters. I believe it is gravity that allows the most residual water to rest in the bottom of the pot. Just as in capillary fringe movement of water the greatest concentration of water in the capillary fringe is just above the saturation point, the further away from the water table (going up) the less water is pulled leaving as in a watered tree the top moist, the bottom closest to being wet and the area in between gradually moister from the top down. Hence, when checking to make sure your trees are ready to water we poke into the soil beneath the surface as the surface dries first, the botom dies last.

Jay,
In Bloomington, Illinois on west washington street there is a materials/gravel dealer...the name escapes me. I believe it is near the intersection of washington and Morris..on the west side of the RR tracks. About 25 minutes from Lincoln.



They sell haydite (expanded/baked shale) for about $20/ton. GREAT Stuff, irregular particles, uniform color, water retentive, stays crunchy in milk.

I have a very similar product in Oklahoma (just a different color), It has such water retentive properties that I use it straight with none or very very little organic matter. This is for deciduous, conifer AND a few Tropicals. Keep in mind I use this in Oklahoma where it was 103 for a large part of the summer!

Use the KISS principle. Just be sure to sift & read Walter Pall's soil write up on his blog. If you can get great results with as little work and cost as possible, do it.

Actually, fluid mechanics involves the entire picture of how the water (in this situation) interacts with the entire environment it encounters. I believe it is gravity that allows the most residual water to rest in the bottom of the pot. Just as in capillary fringe movement of water the greatest concentration of water in the capillary fringe is just above the saturation point, the further away from the water table (going up) the less water is pulled leaving as in a watered tree the top moist, the bottom closest to being wet and the area in between gradually moister from the top down. Hence, when checking to make sure your trees are ready to water we poke into the soil beneath the surface as the surface dries first, the botom dies last.[/quote Jay]

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OK, If the only force that moved water was gravity there would be no residual water at the bottom of the pot if the container has positive drainage and trees could not grow taller than three feet. As a matter of fact some trees can grow to 130 meters in height before gravity force over powers capillary force.






Ciao....Leonardo

I'll jump in discussion with something along Leonardo's thread. Take 2 6-12 oz. plastci,prefer. styrofoam cups. Fill 1 cup completely to top with water(ok,have 12 oz. water) Fill other 12oz. cup with your soil mix(cubic volume). Immediately pour water from 1st cup into your soil mix and measure amount of water loss from 1st cup. Wait 24 hrs. and repeat water poring from full cup into your soil mix. You can try experiment with different soil mixes in same envirment for measure of water retention and gravitional pull. For myself(greenhouse+halide lights) it is 80-90 degrees warm days. I use completely inorganic growing medium for almost all my trees(Lava Rock/Turface-about 75-25%) I use completely organic feeding schedule of grandular plus regular liquid fish emulsion deluded. I had tried Haydite(Shale) but when re-potting tree in 30x20x5 pot the Haydite was much,much heavier to lift than Lava Rock(well both are potential hernia) So for lightness, this told me Lava rock had greatest water retention per cubic volume of soil. The Lava rock also took in and lost the greatest amount of water hands down. Hope this may shead some light on water,gravity. Dustin Mann

leonardo wrote:Actually, fluid mechanics involves the entire picture of how the water (in this situation) interacts with the entire environment it encounters. I believe it is gravity that allows the most residual water to rest in the bottom of the pot. Just as in capillary fringe movement of water the greatest concentration of water in the capillary fringe is just above the saturation point, the further away from the water table (going up) the less water is pulled leaving as in a watered tree the top moist, the bottom closest to being wet and the area in between gradually moister from the top down. Hence, when checking to make sure your trees are ready to water we poke into the soil beneath the surface as the surface dries first, the botom dies last.[/quote Jay]

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OK, If the only force that moved water was gravity there would be no residual water at the bottom of the pot if the container has positive drainage and trees could not grow taller than three feet. As a matter of fact some trees can grow to 130 meters in height before gravity force over powers capillary force.






Ciao....Leonardo

No one said the "only force" was gravity, BUT, since you mention it, there is a reason why, even if you totally submerge the pot in water until all air has been replaced with water, then allow the soil to drain, you will find the pot will reach a point where the moisture in the top of the soil decreases and the water retention increases with depth in the pot. The pot will also dry faster from the top down. Even though air has access to the soil at the top and adjacent to all surfaces in contact with the mesh of the pot. Yes the soil attempts to equalize, yet it still dries top down with the bottom of the soll drying last.

I use what I was recommended by Corin Tomlinson: Two parts peat, two parts grit, one part John Innes Number 2. seems to work

irene_b wrote:I have also seen this in action...I place a larger particle on the bottoms of my pots because of this..
Irene

Great point you raise here!

This is a myth that needs to be debunked. Yes, I know the Japanese and many others still use a drainage layer, but it serves no useful purpose in bonsai. A drainage layer was indeed used at one point in time when pots did not have drain holes (household plants) to permit excess water a place to go. However, even this method did not ensure that your potting medium did not remain wet at the bottom.

Speaking of fluid mechanics, pot size transportation etc... this is the simplest test of all, it does not need laboratory conditions or correlated scientific data to execute.

Many folks do not fully understand the term perched water and how it affects watering and water retention, or how a shallow pot of a given volume will retain more water than a deeper pot of equal volume, regardless of soil composition.

The test...

Take a simple 2x5x1/2" kitchen sponge place it on a rack over the sink, the latter could be a baking cooling rack, anything that will allow the sponge to lay flat. The sponge represents the soil, any soil.

Now thoroughly saturate the sponge (soak it in a bowl) then place on the rack (large surface down) and allow it to drain. When the sponge stops dripping, turn it on it's edge so that it is 2 inches high and see how much water drains out, additional water you did not think was still present. After the sponge has drained, turn it on it's end so now the height of the sponge is 5 inches, see all the water that is still coming out of what we thought was a thoroughly drain sponge. It's amazing and why is that? The sponge's volume never changed during this experiment, it had a given holding capacity and water drained out until the surface tension of the water equaled that of the medium containing it. In other words the weight of the water was greater because of the height of the column in any given container etc... Once this tension equals the opposing tension provided by the substrate, it stops to drain as all is in balance.

Now think of the drainage layer at the bottom of the pot as the rack above you sink. A drainage layer will provide a medium which provides lesser tension therefore the water will flow right through it, the trapped water (perched water) will still be in the finer course of substrate, regardless of what that size is, therefore the drainage layer provides no useful purpose.

This explanation is what Leonardo was trying to say...

Container size, transportation and evaporation.

In bonsai aesthetics we want a pot depth which equals the trunks diameter, etc, etc, etc... This in turn could be a pot that retains a lot of water/moisture. Because the pot is shallow more than likely the roots (at the bottom) will always be wet, not a good thing, compare it to trench foot of WWI. So how do we avoid this? By constructing the substrate in such a way as to reduce the surface tension e.g larger particles, or a greater % of aggregate (components that retain little moisture) in comparison with components with water retention capacity.

That is why there is no magic soil recipe, only what works in your area, your pot size, soil composition and a substrate that will retain only enough moisture to compensate for evaporation and tree perspiration on any given day, sometimes a requirement to water more frequently. It is better to water more frequently than have a tree stagnating in a pool of water, your trees will love you for it and will respond accordingly, a healthier tree.

Rick is correct about the "drainage" layer as well as that there is no magic soil recipe. The truth is that bonsai can be grown in practically anything that is not toxic. See "The Secret to Soil Revealed" at http://knowledgeofbonsai.org/articles/care/soil-potting-media/the-secret-to-soil-revealed/

[quote="Rick Moquin"][quote="irene_b"]I have also seen this in action

This is a myth that needs to be debunked. Yes, I know the Japanese and many others still use a drainage layer, but it serves no useful purpose in bonsai.
......................................
Not true


Many folks do not fully understand the term perched water and how it affects watering and water retention, or how a shallow pot of a given volume will retain more water than a deeper pot of equal volume, regardless of soil composition.





This explanation is what Leonardo was trying to say...

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Wow, trees are perspiring. Perched water table would occur if the container had no holes on the bottom or holes in the wrong position to a very small degree. The term that best applies is capillary fringe.

Ciao.......Leonardo

Will Heath wrote:Rick is correct about the "drainage" layer as well as that there is no magic soil recipe. The truth is that bonsai can be grown in practically anything that is not toxic. See "The Secret to Soil Revealed" at http://knowledgeofbonsai.org/articles/care/soil-potting-media/the-secret-to-soil-revealed/

Wrong again and I will reveal why at later date.

Ciao.......Leonardo

Here is one that always grabs me.
"The flow of water is slowed down when there is an abrubt change in pore space."
Could be possible in certain cases.
"A rock layer beneath finer soil will slow down the downward flow of water"
I will take that one to the bank. Wrong

Ciao.......Leonardo

Leonardo.

You remind me of someone else that plays charades. In the intent of learning, the latter is not accomplished by charades. Should you care to argue my point with regards to perched water, may I suggest you take it up with Brent Walston. Failing the aforementioned, show us the money!

leonardo wrote:


Perched water table would occur if the container had no holes on the bottom or holes in the wrong position to a very small degree.

Ciao.......Leonardo

....wrong, that would represent flooding for the lack of a better word!