gypsum

Has anyone tried using gypsum to help with clay soil?

I would have, but I believe the gypsum I had available had a high concentration of calcium. As my soil already has huge amounts of ca, I knew gypsum wasn't the right choice (too much ca is baaad). The only thing I do for heavy clay is organic matter: chopped straw, grass clippings (only on top as mulch and away from stems of seedlings), pine chips and chicken poo, chopped leaves, etc. My soil structure looks "messy" but grows lovely stuff.

Gypsum is calcium sulfate and is a good soil conditioner for clay soils, especially here in the west, as gypsum will help reduce the high sodium levels that are common in more arid areas. Although it has calcium in it, the calcium from gypsum is not always available to the plants. I've needed to add additional calcium to have an adequate amount available for my plants.

Damaged wallboard, or scraps, can be tilled in, I understand (might help to wet it first). If there's any chance of e.g. lead-based paint on it, though, forget it. Ordinary drywall board is gypsum and paper... some has waterproofing such as asphalt, but I think that that's all tinted blue.

Mark., never tried it

Ha, ha, gypsum is calcium sulfate. That would explain the calcium part!

So it might have been a fine choice for me after all, despite my high ca levels. Hmm.

Zeppy, what type of soil test did you use that showed high calcium?
There are several protocols. I've noticed that most county agents will use a soil test where the lab uses a strong acid solution. This is useful in showing the *potential* nutrients in the soil, but it does not show what is *actually* available. The soil tests that use a weak acid solution more closely resemble actual conditions.

No idea! Virginia Tech does it, and they're huge in agriculture, but that's all I know. Maybe I can find out.

Garden_mermaid, Last week I called my County Extension and was told they no longer test soil! So, here in the Bay area, where can I get it tested? I do have a Ph test.

I send my soil to Internation AgLabs in MN because I like their testing program.
My interest is in nutrient-dense, biological agriculture to restore the soil. This is a lab that understands the concepts. I get better results and spend less money (in the long run) on soil amendments and fertilizer by using this approach.

http://www.aglabs.com/

Garden_mermaid. You have D mail.