Re: [CH] gypsum application

Celeste or Dave Anderson (
Wed, 8 Apr 1998 12:25:41 +0000

Here's the scoop on Gypsum (Calcium Sulfate CaSO4)

Gypsum is used to reclaim alkaline clay soils. Sodium atoms attached 
to clay particles cause them to pack tightly together preventing 
water penetration and/or drainage.

Calcium from the gypsum displaces sodium on clay particles. Sulfur 
from the gypsum reacts with the sodium to form highly soluble sodium 
sulfate which leaches out of the soil.

Free of excess sodium, soil particles aggregate to form large 
clusters and pores. Improved water penetration helps leach excess 
salts from the root zone.

 Fortunately, gypsum is Jamaica's second leading mineral export after 
bauxite, so Jim and I recommended that they amend their clay soil 
with it.

Do not try to amend clay soil with sand. You'll end up with cement.

Dave Anderson
Tough Love Chile Co.

> I am going to start my chile garden shortly. This will be the second
> season. My soil is mostly clay. Last year I added some sand, peat moss,and
> some manure. I would like to add gypsum to my beds but I'm not real sure
> on the rate to apply and also will it affect the chiles so close to
> planting time. I know Jim Campbell of Mild to Wild talks about this in
> the Technical report from Jamaica. I need some advice. 
> I also had a problem with my Red Savina in a container last year. After a
> good start and about 20 fruits the plant lost all leaves. Jim told me to 
> put it in the shade and feed it. It worked ok. I would like avoid this
> problem this year. 
> Steve