Today, I went to buy gypsum to apply to my clay soil before the winter
rains begin. While I never buy plants at a hardware store or lumber
yard, I do buy tools and supplies at such stores.

I went to a nearby hardware store (about 3 miles from my house) and took
a 40-pound sack of gypsum to the register. With a senior-citizen
discount of 5%, the clerk said that it would be $12+change. I left the
sack at the register and drove to a favorite nursery about 12 miles
away. There, I bought a 50-pound sack of gypsum for under $9.

That is correct: 25% more gypsum for 25% less money. Both were 92%
CaSO4 (calcium sulfate).

--
David E. Ross
Climate: California Mediterranean, see
http://www.rossde.com/garden/climate.html
Gardening diary at http://www.rossde.com/garden/diary