Using Scrap Drywall to Amend Clay Soils?

Mon May 08, 2006 7:11 am

I've done some research to see if adding gypsum to clay soils helps loosen them up. Half of the stuff I've read says that's an old myth. The other half reports that gypsum allows the clay particles to "flocculate" (clump - had to look that one up) and thus improves drainage.

From what I understand, gypsum (calcium sulfate) does not raise the pH of soil the way that lime (calcium carbonate) does. I have heavy clay soil and a bunch of scrap drywall, so I thought about grinding it up and applying it to my fields.

Does anybody have any real world experience with this? Thanks in advance.

Blair Mahar
Savoy, MA

Mon May 08, 2006 5:01 pm

Blair A farmer friend of mine near Lake Senneca said that they added Gypsum to his heavy clay soil just for that purpose. Your place looks as if it has the same red brick clay we have on Staten Island. I covered the whole garden 25 years ago with sheet rock scraps one fall by spring paper was off and mostly broken up. The following spring I turned it all in. I no longer have stickey red clay. Of course the truck loads of road apples through the years and loads of leaves helped too. I have no scientific proof the gypsum helped but the soil didn't pack as hard when it dried in the summer.


Tue May 09, 2006 11:21 pm

300 to 500 pounds per acre is what we use in my area. No, it will not change ph measureably. It will however add sulphur, which is needed in many soils, and improve drainage and tilth. I'm refering to the scrap material bought from the manufacturer which is in part unsalvageable gypsum board.

Wed May 10, 2006 9:59 am

Hi Bill,

Good to hear from you. We actually have thick grey clay here in Savoy. I have a big field out back that I'd like to plant a food plot in, but the drainage is really bad. I'm thinking about putting in 4 inch tile and seeing if I can improve the field that way. Just recently I've been reading up on gypsum. Thanks for your input.

Thank you as well Lil' Red. I appreciate your input.

Blair Mahar
Savoy, MA

Tue Jun 20, 2006 6:48 pm

Besides gysum to loosen clay soils, yellow clover works well for me. In the garden I use red mangle beets.