Root Growth: Soil vs Bonsai Soil

[Jzack605]

So this has been on my mind since I got deeper into bonsai. As far as root growth goes; what is the pluses and minuses of normal soil vs bonsai soil when training in regards to roots? Normal soil has the benefit of more available nutrients and water retention whereas bonsai soil is more porous I THINK would encourage root growth to “find” the water. Any thoughts?

 

[Smoke]

Bonsai soil is exactly the same thing as what you deem "normal soil". The only difference is the particle size.

If you went out into a field and brought back a pickup truck full of field soil (normal soil) and allowed it to dry and sifted it for size keeping only the 6 to 7 mm particles, you would have a pretty good bonsai soil. If you could find a clay field, that would be even better because clay particles resist breaking down longer.

Bonsai soil thrown on the ground and left there will eventually turn into "normal soil" thru erosion weather break down, animal wear, human wear, or vehicle wear. It will become very fine powder if left long enough. Then in 50 years some guy will see this and say this is "normal soil" I heard this was not good for bonsai!!!

 

[River's Edge]

So this has been on my mind since I got deeper into bonsai. As far as root growth goes; what is the pluses and minuses of normal soil vs bonsai soil when training in regards to roots? Normal soil has the benefit of more available nutrients and water retention whereas bonsai soil is more porous I THINK would encourage root growth to “find” the water. Any thoughts?

There are two excellent articles in the resource section of this forum that will answer your question. Dig in!

 

[sorce]

It depends how you use your soil.

For me, Black Soil and wet Clay soils are for the ground only. Too mud in pots.

Nursery Soil, and other organic soils make long roots.

Roots in DE are almost 100% feeders.

Sorce

 

[just.wing.it]

I think one problem that people experience with "dirt" or "field soil" or bagged "potting soil" is root rot.

Not only the particle size, but the material that those particles actually are, will determine how much water the mix holds.

You see more conversation about inorganic vs organic material for soil mix, than about particle size....both are very important however.

In general, organic material holds more water.....and the smaller your particle size is, the more water it will hold.

The asterisk goes next to the inorganic mixes, because there aren't any nutrients in there for the tree.....that's where fertilizing comes in.

I personally prefer lava and pumice with a good layer of sphagnum on top....I also like DE, Haydite, and Turface as additives.
This year I'll be trying a bit of Fir Bark chips in with my lava and pumice....

Soil mix for bonsai will differ depending on your microclimate, and ability to water....
For example, I moved in 2018, in June.
My old house had many huge beech trees and poplars, shading the area for most of the day, and watering was not a problem, just morning and evening.
At the new place, I'm on top of a ridgeline, in full sun....and I'm farther away from work, so I don't get home until later, sometimes I'll be out from 5am to 8pm, and when it's hot and breezy, my trees dry out fast.
That's one reason why I will be experimenting with adding bark to my soil mix this year, for more water retention.
As well, I'm going to be using a thick layer, at least one inch of chopped sphagnum moss on all the trees that need it.....that sphagnum on top can be all the difference.

 

[Lou T]

So this has been on my mind since I got deeper into bonsai. As far as root growth goes; what is the pluses and minuses of normal soil vs bonsai soil when training in regards to roots? Normal soil has the benefit of more available nutrients and water retention whereas bonsai soil is more porous I THINK would encourage root growth to “find” the water. Any thoughts?

“Normal” soil contains a massive spectrum of constituents. The three general types are clay, silt and sand. Each of these contains many sub-categories. Humus is generally a term used to describe the organic content in a given soil. Again, this is a very complex topic and soil science is a massive field. The smallest variation in soil composition can affect a plant drastically. Just ask a viticulturalist.

Bonsai soil, generally speaking, is a fast-draining mixture largely free of organic content. Again, a very general description. Though some soil geeks here may disagree, bonsai soil is far less complicated than “normal” soil you’d find in various places. The reason is, “normal” soil is cultivated by nature over time and contains many many natural denizens(varying of course). Whereas, with bonsai soil, the artist usually builds the soil. If you were take a cross-section of life of forest duff compared to bonsai soil, you’d see a drastic difference. The forest soil would appear to be crawling where the bonsai soil would be rather sterile.

 

[Vance Wood]

The most important aspect in any bonsai soil is its ability to maintain structure and not break down too quickly. More to follow.

 

[rockm]

So this has been on my mind since I got deeper into bonsai. As far as root growth goes; what is the pluses and minuses of normal soil vs bonsai soil when training in regards to roots? Normal soil has the benefit of more available nutrients and water retention whereas bonsai soil is more porous I THINK would encourage root growth to “find” the water. Any thoughts?

you're confusing what bonsai soil is about. Using bonsai soil has nothing to do with the soils' relative "nutritional" value, if you've got your tree containerized. "Normal" soil from the ground will kill containerized trees in the long run, but mostly in the short run. "Normal" dirt doesn't drain very well when put in a container. Normal dirt drains when it's in the landscape, because in that situation, it has mostly infinite drainage capabilities. In a container, you have defeated 99 percent of those possibilities. Simple matter of physics. Pots tend to have limited drainage compared to soil. On top of that, they also concentrate roots into a very small area, which is subject to intensified wet and dry conditions...

Bonsai soil is deigned and put together by people to drain VERY VERY well in containers. Drainage is the soul of bonsai. They can't live without it.

In such free draining soils, the plant relies ON THE PERSON TAKING CARE OF IT to supplement the nutrients with fertilizers as well as water supply. Application of ferts can be carefully controlled to produce specific results in bonsai soil and in containers, as can water.

It's up to the grower to supply all the plant needs in a container. Soil can't and shouldn't do it. You've containerized it for a reason, to develop it in a controlled way....

However, that development is mostly REFINING a tree's finer points. By the time the tree makes it into a container, it's big parts--trunk, surface roots (nebari) should be mostly developed. This bulk work is better done in the ground in "normal" soil, as the plant has mostly unlimited resources in the ground--room to push all the roots it wants to gather as much resources as it can. That ability means it can put on a lot of growth in a shorter period--however, that growth is coarse and mostly un usable for bonsai--trunks bulk up quickly, limbs thicken too. It's up to the grower to tell WHEN enough growth is enough for bonsai purposes.

Both "normal" and bonsai soil have their uses. You have to know when they're appropriate...

 

[Forsoothe!]

Different strokes for different trees. Those that grow in scree in the wild may do poorly in slower draining soils, so "bonsai" soil is helpful in allowing the roots to be dry, more or most of the time. There are lots of woody plants that don't grow well on mountainsides and do well in "dirt".

The problem with this conversation is that the JBP Purists will want to make blanket statements about drainage which apply in spades to some trees, but not to the same degree with other woody plants. This will be more of a "not invented here" argument than it will be about the finer subdivisions of plant care.

Any needed constituents of soil mixes not included will have to be provided by the caregiver. The Purists will claim to do this, timely, and those with gardening backgrounds will question whether that is really a practical substitute for a proper "soil" with a high humus content, a full range of micro-elements and supporting cast of enzymes and microscopic critters what do their thing processing elements into food for plant life. With good soil, you don't actually have to "know" who's in there and what their doing. Farmin' has been goin' on for quite a while.

As to the drainage boogyman, the pines and their ilk need more than most other trees (do NOT bother specifying the others that just muddies the water, -we know they exist), but most will do just fine in good soil. I have never used "bonsai" soil in 20 years and have lots of trees in good health for a long time. Holes in pots do the drainage.

Here's something you can really sink your teeth into: root-rot is a problem for bonsaiists, but few others complain about it. Bonsaiists use rocky mixes which are reguarded as "poor, nutrient dificient, nearly lifeless mixes" by everybody else in horticulture, but others use high humus and bark-rich mixes. Do you see the metaphor here? Maybe, root rot is a problem of crappy bonsai soil, not soil soil? Huh??

 

[rockm]

Different strokes for different trees. Those that grow in scree in the wild may do poorly in slower draining soils, so "bonsai" soil is helpful in allowing the roots to be dry, more or most of the time. There are lots of woody plants that don't grow well on mountainsides and do well in "dirt".

The problem with this conversation is that the JBP Purists will want to make blanket statements about drainage which apply in spades to some trees, but not to the same degree with other woody plants. This will be more of a "not invented here" argument than it will be about the finer subdivisions of plant care.

Any needed constituents of soil mixes not included will have to be provided by the caregiver. The Purists will claim to do this, timely, and those with gardening backgrounds will question whether that is really a practical substitute for a proper "soil" with a high humus content, a full range of micro-elements and supporting cast of enzymes and microscopic critters what do their thing processing elements into food for plant life. With good soil, you don't actually have to "know" who's in there and what their doing. Farmin' has been goin' on for quite a while.

As to the drainage boogyman, the pines and their ilk need more than most other trees (do NOT bother specifying the others that just muddies the water, -we know they exist), but most will do just fine in good soil. I have never used "bonsai" soil in 20 years and have lots of trees in good health for a long time. Holes in pots do the drainage.

Here's something you can really sink your teeth into: root-rot is a problem for bonsaiists, but few others complain about it. Bonsaiists use rocky mixes which are reguarded as "poor, nutrient dificient, nearly lifeless mixes" by everybody else in horticulture, but others use high humus and bark-rich mixes. Do you see the metaphor here? Maybe, root rot is a problem of crappy bonsai soil, not soil soil? Huh??

Oy...freaking vay....this argument was left behind about 30 years ago...with soil mixes that included "loam" Let me tell ya that root rot is mostly NOT a problem for bonsiaists using well draining soil or soil less mixes. It is HUGELY more prevalent in "humus rich soil" in containers than in free draining soil. Been that way for a very very VERY long time. The switch to freer draining soil and away from dirt-based mixes PRODUCED the revolution the bonsai hobby has experienced in the last three decades by mostly doing away with the common issue of root death and allowed quicker recovery.

Oh, and bonsai mostly developed in China and Asia because alot of the soils native to those countries are VOLCANIC--light, porous and FREE draining that naturally perform well in containers..take a look at akadama, kanuma, etc. NOT DIRT....

 

[Forsoothe!]

Baloney. Nobody uses "soil" but me. The people reporting root rot is you, not me. How do you account for that?

 

[bonsaichile]

Baloney. Nobody uses "soil" but me. The people reporting root rot is you, not me. How do you account for that?

Once again, the argument should be decided by the trees. Boon has his own mix, and amazing trees. Walter Pall works with a mostly inorganic, extremely free-draining mix, and his trees are superb. Can we see yours or an example of world class/highly refined trees in potting soil?

 

[LanceMac10]

Once again, the argument should be decided by the trees. Boon has his own mix, and amazing trees. Walter Pall works with a mostly inorganic, extremely free-draining mix, and his trees are superb. Can we see yours or an example of world class/highly refined trees in potting soil?

If a not so nice tray planting pops up, I'm going to have a chuckle.....

 

[rockm]

Baloney. Nobody uses "soil" but me. The people reporting root rot is you, not me. How do you account for that?

You don't know what you're doing?

 

[Smoke]

You guys are so far away from the question it is why nothing ever gets solved here. The question is answered by particle size pure and simple. There is no reason to go into mechanics or organic versus inorganic or root rot or no root rot. The question is what’s the difference between what a bonsai person would use versus dirt. End of story.

Your super duper bonsai soil is dirt, before it has broken down. There is not one constitute in bonsai soil that does not come from the earth in a form we deem chunkier than what we call dirt. Period.

And..... potting soil can make a very good bonsai soil with the addition of course sand or pumice or scoria. It just needs the addition of something to prevent compaction.

The soil revered by many, akadama is dirt. It is clay dirt that sticks together very well and allows itself to be sifted and graded. When it melts or “breaks down” it turns back into dirt. That’s what it is.

 

[Forsoothe!]

Sure. I'm not a Walter Pall, but I have a dozen trees that I've had from my 1st years. I've been a serious gardener for 40 years and I pride my garden as having many trees that visitors have never seen in the flesh. Same with my bonsai, many are unusual because I love a challenge. That includes learning how to grow difficult plants.
https://www.bonsainut.com/threads/show-us-your-bonsai-benches.31934/page-5
https://www.bonsainut.com/threads/indoor-bonsai-displays-lets-see-them.36642/page-2
https://www.bonsainut.com/threads/indoor-bonsai-displays-lets-see-them.36642/page-3

 

[Dav4]

Don't forget the shallow containers we tend to plant our trees in. I can grow all sorts of species in a nursery can full of soil conditioner and turface... throw the same tree and soil mix into a wide and shallow stoneware oval that's only 1.8 inches tall and I'll have a tree with some root issues in no time.

 

[River's Edge]

I was hoping that referring to factual information and well documented reasoning would allow the OP to gather the information they were seeking without exciting the trolls lurking under the bridge. Silly me!

Reproduce the optimal root growth environment with whatever materials will provide and maintain air porosity and water retention within the acceptable ranges for your species, climate, containers and care practices. Provide nutrients either within the components or in addition to. Understand the difference in using shape and size of various containers and the impact on water retention.

Smoke is correct, particle size is a key factor. Shape and structure also play a role in the effectiveness of the components. PH of the components also play a role. All of this information is referenced and documented in the forum resource section.

 

[coh]

View attachment 228513View attachment 228520View attachment 228515View attachment 228516View attachment 228517Sure. I'm not a Walter Pall, but I have a dozen trees that I've had from my 1st years. I've been a serious gardener for 40 years and I pride my garden as having many trees that visitors have never seen in the flesh. Same with my bonsai, many are unusual because I love a challenge. That includes learning how to grow difficult plants.
https://www.bonsainut.com/threads/show-us-your-bonsai-benches.31934/page-5
https://www.bonsainut.com/threads/indoor-bonsai-displays-lets-see-them.36642/page-2
https://www.bonsainut.com/threads/indoor-bonsai-displays-lets-see-them.36642/page-3

So you said earlier "I have never used "bonsai" soil in 20 years and have lots of trees in good health for a long time." What are you using?

 

[Forsoothe!]

So you said earlier "I have never used "bonsai" soil in 20 years and have lots of trees in good health for a long time." What are you using?

I would like to be further attacked by people presuming this, and assuming that, and absolutely believing there is but One Great Single God-Like Plan for all and failure to follow directions of Il Cognoscenti will result in the wholesale collapse of all things woody. When all of them are sufficiently far out on the limb, I'd be more than happy to saw it off.

Let's start with how bad my dirt trees look.