Re: [CH]V5 #270 pH testing & challange
Cameron Begg (begg.4@osu.edu)
Thu, 25 Mar 1999 08:31:56 -0600
Hi C-H's,
Harold Eddleman wrote:
>This old house has always been heated by wood and the
>ashes went onto the garden for 80 years that I know about. Wood ash is
>much higher in Na2O than K2O. Thus, wood ashes may not be as good for a
>garden as generally believed.
I might use them on a compost pile, but never on the garden. As you point
out, wood ash contains alkali metal oxides which dissolve in water to form
hyroxides and a very basic (alkaline) solution. Back in early settler days,
such solutions were boiled with rendered fat to produce soap. I seem to
remember dimly that the grandmother in "Beverley Hillbillys" used to do
this.
>I fertilized with
>liquid plus phosphoric acid. I mixed that in a barrel and pumped that
>onto the sweetpotato beds and caught the water that came through for
>analysis. I applied lots of fertilized water so that 1/2 ran thru the
>sand to wash out any accumulated salts. The pH of the water going in
>was 2 or below, but the water coming out was nearly 7! Sand is a poor
>buffer, how could the pH change so much in a minute or less?
I can only guess that the sand was not pure silica. If it contained crushed
limestone, dolomite or reasonable amounts of clay minerals you could have
ended up with calcium and magnesium phosphates.
Just a thought, but if you want to get rid of your wood ash, you could
neutralise it with the phosphoric acid and make a useful plant food.
BTW Harold; thanks for a sensible reply :-)
Regards, Cameron.