Sheetrock as a Gypsum Source
Crop and Soil Environmental News, July 1999
Extension Specialist, Soil Testing and Plant Analysis
I received a request from a homeowner who asked me if it was safe to use sheetrock as a calcium source for his vegetable garden to improve the friability of his soil. I called the Product Safety Office, U.S. Gypsum, and was informed that the gypsum contained within the sheetrock was safe to use and that the wallboard exterior was normal pressboard paper with no toxic components. It was stressed that the sheetrock needed to be pulverized first to react well with the soil.
It is important to note, however, that gypsum is not any more effective in Virginia for improving the friability of the soil than regular limestone. Out in the Far West on certain alkaline soils where limestone is not needed to neutralize soil acidity, the calcium from gypsum is used to replace sodium in the soil, which makes those soils more friable. The same is not true, however, for Virginia soils because we do not have excessive amounts of sodium in our soils. We also need to lime our soils periodically which supplies abundant amounts of calcium for optimum plant growth.