I have found that when I stick my neck out, by some mirqacle, I am readily corrected, and learn; so here goes.
Peat can yield up to 4.0-5.0 pH "soil," if used nearly full strength.
To bring this to neutral, lime is used... but;
Gypsom, strangely, "buffers" (is the term) pH, in BOTH directions.
I cannot say to what degree/amount.
But the gypsom I get is a compact 40 lb bag for ~$7-8 and has details on the back.
You could get a pH test kit and mix a known amout in say, 3 differing quanities, and check to get about right. Remembet that pH is a 10x (10 fold) exponential scale. 5.0 pH is 10x as acid as 6.0 pH... So doese tests accordingly.
Cordially,
BillSF9c
San FranCisco, CA, pseudo USDA Cold Hardiness zone
--orig msg--
From: BekeeprTop@aol.com
Subject: [NAFEX] augment peat with gypsum?
To my cold frame I just added one 3.8 cu foot bag of peat moss. Would there be a consensus that besides adding a couple buckets of my compost that I would be well advised to add some gypsum [calcium sulfate]? I believe the peat is considered quite acidic by itself. I have gypsum....how much might I add along with that 3.8 cu foot bag of peat?