Thread: Question on "Boon Mix" soil
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Old 14-Dec-2005   #2
Carl_Bergstrom
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Join Date: May-2002
Location: Seattle, WA.
Country: USA
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Quote:
Originally Posted by darrellw
According to http://www.bonsaikc.com/bonsai_soil.htm, Boon suggests the following mix:

1 part lava rock
1 part pumice
1 part akadama
1/2 cup horticultural charcoal (per 5 gallons mix)
1/2 cup decomposed granite (per 5 gallons mix)

My questions:

What is the purpose of the charcoal? I've never seen it recommended in other mixes, but is is cheap and easy to got, so I just wonder what it does. Is if for the cation exchange capacity?

What is the purpose of the decomposed granite? It seems too little for "structural" reasons, but I would think it would be pretty inert.

Would a calcinated clay product (Turface and such) be a reasonable substitute for the akadama?



I've used Boon's mix for several years with great results. I believe that the charcoal keeps the soil from going too sour (acidic). I don't typically use the granite because it is not readily available here; I believe that its purpose is to add sharp edges to the soil.

Boon argues that turface and such are not an adequate substitute of akadama.

Best regards,
Carl
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