Biochar use in bonsai soil

I read a study a while back that showed biochar can help the survival of mycorhizae by adding spaces for it to exhist that nematodes could not fed in. Biochar has also been used in some soils to increase CEC. I was watching a Marai video where Ryan basically pooh-pooed biochar but was very vauge about why. I couldnt help but wonder if there may be a place in bonsai soil for biochar. Perhaps to preserve mycorhizae in nematode treated pots or as a poor man’s akadama supliment?
Has anyone successfuly used biochar or found that there is a major failing in it for bonsai soil application?

Thank you.


I’ve started incorporating small amounts of horticultural charcoal into my soil mix (generally a pumice/lava/akadama base). I haven’t been using it long enough to determine if there’s any noticeable difference. However, what I’ve read about it suggests to me that it can serve as component that can further enhance the cec (ability of the soil to hold onto nutrients), while holding up better than other organic components like bark, which used to be widely used as a component.


In the far past I looked up biochar and used horicultural charcoal in my repot process to sweeten the soil. At the time I lived in the Palmdale, Ca. which is in the High Desert of Northern Los Angeles. I never saw any change in results that actually made a difference either above or below the soil.

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I wanted to take this thought a step further. Ryan talks a lot about finding a substitute for akadama and personally I would love that. It seems kind of crazy to rely on a soil component shipped in from another country, especially since the quality seems quite variable from batch to batch. Anyway, I’ve been wondering if charcoal might be able to serve as a substitute for akadama - either alone (probably not) or perhaps in combination with another ingredient, such as DE. So maybe instead of akadama, use a 50/50 mix of charcoal and DE?

Thinking - charcoal serves the dual purpose of water holding and providing CEC. It is organic so I believe it would gradually break down over time - not as quickly as akadama, but I don’t know how quickly compared to, say, bark or decomposed bark (soil conditioner) that some use. Maybe roots would be able to penetrate particles…don’t know. Maybe I’ll try some experiments with some of the excess seedlings/cuttings I have sitting around.

Anyone have any thoughts/experience with this? I have no idea what (if any) pH impact there would be.

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i know that soil types will affect the rate at which biochar decays. also ash is caustic so but you could rinse and strain the charcoal Bessie adding it to soil and it shouldn’t affect the ph too badly.

ill have to do some digging into the sill types and report back.