Ask A Scientist General Science Archive

name peter
status other
grade other
location IL

Question - I have heard that charcoal ash from my barbque grill is
good plant food/fertilizer.
Can you verify please.
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I am sure it is helpful, Peter.
It may have some minerals which your soil may be poor in.
It should add some durable porous solid substance to the soil,
which is a protected home for bacteria to grow in,
and gives another place for water to be stored between rains or watering.
Bacteria can help plants by fixing nitrogen in the soil, which most plants 
need.
Merely pulverizing your brand-new charcoal would have the same effect.
Often, much of your ash _is_ unburned charcoal. This is good for soil.

Some self-starting charcoal is done by adding oxidizing salts to the 
charcoal.
This type might have somewhat different effects than plain charcoal.
Maybe worse, I'm not sure.
Certainly it could be stronger acid or alkaline addition to your soil.
Too strong would be bad, but not permanently bad.
They also might be adding salts to your soil, not beneficial.

Jim Swenson
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