Vegetables Gardening - Growing Organic Vegetables

In my old book, gypsum and dolomite are both referred to as lime. Lime is usually readily available at hardware stores and masonry supply stores as it is used in mortar and concrete. I have heard of quicklime and slaked lime. Plaster of Paris is also called gypsum lime.

I have no idea if these are suitable for the garden or how to calculate amounts to use.

Common sheetrock is gypsum board, and it disintegrates when it gets damp. But I think all of the newer stuff has a mold inhibitor in it, so it's probably not good for gardening. Perhaps someone out there would know?

Bryan & Group:

Lime and gypsum are both sources of calcium, but gypsum has sulfur in it and lime does not.

Lime raises soil pH, and - because of the sulfur - gypsum does NOT.

Therefore, for gardens with pH above 7 use gypsum, and for those with pH BELOW 7 use lime.

Most sources of calcium are fairly close in the amount of calcium, so we standardize on the 1 ounce per running foot of soil-bed or Grow-Box.

gypsum board can be used as a last resort.

Jim Kennard

• New Members 25