On Saturday, July 26, 2014 7:16:37 PM UTC-4, David Hare-Scott wrote:
Terry Coombs wrote:

We're building a house , and I find myself with small pieces left

over . Are these any good as a soil amendment ? Gypsum iis the main

ingredient , and I don't know if it acidic or basic . I don't really

have any other way to dispose of this stuff , if I can add it to my

compost heap that'd be a double plus .



Gypsum is calcium sulphate and is close to neutral acidity. It will not

alter soil pH.



It would only be of value if your soil would benefit from it. It is often

used to break up clay and it does work but it takes time and quite a bit to

do so.



The problem with plasterboard is that it is in chunks where agricultural

gypsum is a fine powder. Assuming there is enough to do any good the board

will take very much longer to work (if at all) as gypsum isn't very soluble

and needs to be finely divided to get into the soil. This is exactly the

same problem as those with marble chips wanting to raise pH, it's too

coarse.



--

David



- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

A better world requires a daily struggle

against those who would mislead us.

Within two years you won't be able to find a chunk anywhere. I've done this many times on clay gardens.