North American Fruit Explorers mailing list at ibiblio

[Jim Fruth <jfruth@uslink.net>]

    Hardwood ash, or any ashes, for that matter is/are a fertilizer in that
it/they are a source of potassium that can be readily used by plants.  The
problem with ashes used as a fertilizer is that it contains potassium
hydroxide which is only a slight step less toxic than lye (sodium
hydroxide).  Ashes also contain a bit of sodium hydroxide plus some
insoluble phosphorus.  The phosphorus can be used by plants only after soil,
bacteria convert it into a more soluble form.  Ashes contain nearly zero
nitrogen.
    Really, though, ashes is/are close to the worst form of fertilizer
unless your soil is too acid and you want to sweeten it.

Jim Fruth
Pequot Lakes, MN