Why organic soil?

[Salvarez]

Saw this post by a bonsai nursery in France. Looks like they’re using organic soil to repot?

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[Leo in N E Illinois]

At least the trend in the USA is to avoid organic soils. But if you understand how & when to water and fertilize, organic can work.

 

[leatherback]

Less watering.
Particularly useful if you have many trees and live in a dry climate.

 

[Leo in N E Illinois]

Myself, my go to component is pumice, usually pumice plus one or two other ingredients, akadama, bark, or other similar.

 

[vp999]

I sometime mix a bit of organic soil to my inorganic for my tropicals.

 

[Joe Dupre']

Organic soil grows trees quickly and bonsai soil slows them down. Pick the one that's the best for the tree in its current stage.

 

[leatherback]

Organic soil grows trees quickly and bonsai soil slows them down.

Stated as a fact, but I am not sure this is true.
why do you think this is true?

 

[Wires_Guy_wires]

I use organic soil for trees that need to get bigger. And I'm getting good results.

 

[ShadyStump]

I find it difficult to convince myself to use all inorganic soil. It means you have to fertilize every week or so, watering twice a day, and it feels like it's completely unnatural for the tree.
Like most things, it's a trade-off: higher maintenance for greater control. I have nothing at the moment that warrants that level of control, and the level of care is impractical for me.
I'm still setting into a soil mix that's right for me, but I'm certain for now that it would be heavy on organics.

 

[Lorax7]

I find it difficult to convince myself to use all inorganic soil. It means you have to fertilize every week or so, watering twice a day, and it feels like it's completely unnatural for the tree.
Like most things, it's a trade-off: higher maintenance for greater control. I have nothing at the moment that warrants that level of control, and the level of care is impractical for me.
I'm still setting into a soil mix that's right for me, but I'm certain for now that it would be heavy on organics.

Maybe the climate is really different where you are, but as a point of reference I have the vast majority of my trees in a completely inorganic mix and I don’t have to water anything except the mame twice a day.

 

[Clicio]

Let me put this kindly:
We NEED organics in the soil mix here in the tropics.
Even for Pines.
Junipers.
Adeniums.
Just inorganics will kill most plants, specially tropicals, if you don´t have the time or the automated watering system to water them three or four times a day in the summer.
So Pine bark, nursery black soil, and the such will help a lot if your weather is as hot as mine in the summer.
In the Winter the weather around here is dry, and in the Summer very wet, it rains almost every afternoon. So we have no issues with organics in the Winter, at all.
I never ever killed a tree by overwatering it, but I certainly did kill some by underwatering them. We have a say around here:
"If in doubt, water it."

 

[johng]

Stated as a fact, but I am not sure this is true.
why do you think this is true?

It's very true in my garden but I am sure different climates can vary the success rate...in 30+ years of keeping bonsai I have never once had anything I would call root rot.... Truth of the matter is I believe that APL is a mix for bonsai pros and advanced hobbyists only and should never be recommended to folks new to bonsai...particularly in warmer climates...I would guess that recommendation alone has killed more plant material than any other single recommendation. People need to learn their capacity for watering in their specific climate before ever venturing into inorganic soils. Instead of having soil wars we should spend way more time helping folks understand how to effectively water...there are different contributing factors in almost every situation of which soil is only one of the factors...

People will always say 90% of bonsai is learning to water but 90% of the discussions online are arguments about soil............

 

[Cajunrider]

Stated as a fact, but I am not sure this is true.
why do you think this is true?

Outside of the bonsai world, I practice permaculture. After establishing a 12" thick layer of organic, everything grows easier, faster, requires a lot less frequent watering. So yes, I think organic makes things grow faster and help control the moisture in the soil. A lot of the plant needs are being met from the organic layer. I seldom fertilize if at all.
In growing bonsai, I use inorganic to slow down the pace of growth both at the roots and at the top to get shorter internodes and to improve ramifications. Of course, I will have to fertilize when I need faster growth on bonsai.
For my collected trees, since I live in a very hot climate, I often use soil with a lot of organic matter for bald cypress and Mayhaw right after collection to make sure the trees get enough water. Once the roots are established, I reduce the organic and increase the inorganic.
PS: While I am posting mine, I see that @johng is posting very similar thought.

 

[Maiden69]

Organic soil grows trees quickly and bonsai soil slows them down. Pick the one that's the best for the tree in its current stage.

I don't agree with your statement. See why below.

After establishing a 12" thick layer of organic, everything grows easier, faster, requires a lot less frequent watering.

This is the key, less watering, less need to fertilize. All my trees are growing on inorganic soil and I can tell you that their growth has not been slow at all. The draw back of using inorganic is that you need to water and fertilize often in comparison with someone using organic soil. I think that technique has a lot more to do than the type of soil your tree is planted.

The main reason why inorganic is so effective at slowing down a tree is basically the same, you can micromanage the amount of water and fertilizer used, something that only a person with extensive knowledge of organics will be able to accomplish.

 

[Cajunrider]

I don't agree with your statement. See why below.

This is the key, less watering, less need to fertilize. All my trees are growing on inorganic soil and I can tell you that their growth has not been slow at all. The draw back of using inorganic is that you need to water and fertilize often in comparison with someone using organic soil. I think that technique has a lot more to do than the type of soil your tree is planted.

The main reason why inorganic is so effective at slowing down a tree is basically the same, you can micromanage the amount of water and fertilizer used, something that only a person with extensive knowledge of organics will be able to accomplish.

For me, in bonsai I will move to inorganic because organic matter will decay to mush and cause roots problems for potted trees. Of course, the exception will be bald cypress because it loves mush. Even when my BCs are in advanced stage, I think I will always add a tiny bit or inorganic into the soil just to make it happy.
I would not limit the thinking about organic for just watering alone. For me it is both. The organic layer contain a lot of nutrients that the plants need. That's why we even have organic bonsai fertilizers. The inorganic soil help me control the water, the nutrients, and the spacing for root formation. I would not use organic for advanced bonsai for sure.

 

[Maiden69]

For me, in bonsai I will move to inorganic because organic matter will decay to mush and cause roots problems for potted trees.

Yes, which is another reason I am filling my bags with inorganic. Less garbage I need to deal with when I take the trees out of the above ground planter and into bonsai pots. I wouldn't waste money on akadama for that either. Bonsai Block and Monto Clay from Bonsai Jack mixed with pumice. Best thing is that all I need to do is give them a quick power wash and reuse them, try that with organics or akadama... Once they go into pots then depending on the tree I will move to akadama.

 

[SWfloirda]

I have nearly all my trees in inorganic soil and in full sun. I’ve never watered any of them any more than once a day. Maybe it’s the humidity.

 

[ShadyStump]

Maybe the climate is really different where you are, but as a point of reference I have the vast majority of my trees in a completely inorganic mix and I don’t have to water anything except the mame twice a day.

It is. High altitude semi-arid. My pipes froze for the 2nd time this winter overnight, and last summer my chili peppers thought it was too hot. I've been struggling to keep the humidity above 30% in the house for the tropicals since November, and have to put "full sun" trees under afternoon shade by July. Had to water my vegetable garden twice a day sometimes last August.

 

[Leo in N E Illinois]

In truth, the argument organic versus inorganic is a red herring, a false dichotomy. If you use organic fertilizer such as rape seed cake, sugar cane bagasse, cotton seed meal, fish emulsion, sea weed extracts, or any of dozens of other organic products often sold with names involving "bio" and "green" or "gold" or "magic" or "miracle", the result of using organic fertilizer is that the inorganic media acquires an organic component, hence becomes an organic mix.

The organics are food for the mycorrhizal community. In terms of metabolic costs, nutrients in organic forms are least costly for trees to absorb. Nitrates as in chemical fertilizers actually require a significant amount of energy to absorb. Amino acids and ammonia are absorbed with little or no metabolic cost. All three, nitrates, ammonia and amino acids, are sources of nitrogen, with amino acids being the least metabolically costly of the 3 sources for the tree to utilize.

Steady use of organic fertilizer may clog up pore spaces in the potting media over time, but as long as the pot drains easily, no need to rush and repot.

Probably more important than what the media is, is particle size and particle size distribution. Using sieves to eliminate fines and big chunks is the single most important thing to do to improve the quality of your potting media.

Uniform particle size creates the best structure for air penetration into the media. Sieves are the tool to do this.

 

[Clicio]

I have nearly all my trees in inorganic soil and in full sun. I’ve never watered any of them any more than once a day. Maybe it’s the humidity.

It is a very different story being in a real tropical climate. It's not just the heat, it's the hot wind, the temperature variation, humidity in the summer and drought in the winter.
Of course I understand that we are not arguing about this matter; it's just my experience. My plants are doing well with my watering schedule and 1/3 organics in the mix.
Very good discussion, I enjoy learning from other people's experiences.