Where to Get Calcium Sulfate?

Look for Gypsum.

Portland cement is also calcium sulphate, but it is probably more expensive to buy it as such. Lawn gypsum is best, pricewise.

Thanks. I will try again and look for gypsum instead.

Jay Chan

I bought a bag of 40-lb gypsum from a local nursey for only $8. This is $4 cheaper than what I found in an internet mail order site. The downside is that it has been sitting outside and is wet. This means I cannot spread it right away. I probably need to dry it under the sun for a couple days before I can use it. Oh well...

Jay Chan

You got ripped off. $8.00 is too much for a dry bag.

ps..forget the soil massage characteristics it claims on the bag too.

Mix gypsum 50/50 with powdered lime for the best results. The gypsum will loosen the soil and neutralize calcium chloride salts.

How much do you consider as a reasonable price for a 40-lb bag of gypsum? You may be getting it from a farm supply store. I don't know any farm supply store nearby. The closest farm land is multiple-10-miles away. I can only get it from local nurseries. I guess this means I will have to get it where I can find it.

Jay Chan

Thanks for the advice. But the soil test recommendation sheet explicitly states that I don't need to apply limestone in this year. I will pass on limestone at least for this year. I will do a simple pH test next year to see if I need it.

Jay Chan

Forgot . .. gypsum will also bind "sodium" chloride salts! You're quite right about not always needing calcium. Local conditions apply.

Sorry, I don't quite understand the significance of using gypsum to bind sodium chloride salts. I assume this is a good thing, not a bad thing. I assume the salts are from over-fertilizing the soil, and the use of gypsum is a way to remove the salts. Is my understanding correct?

Thanks for any following up info on this issue.

Jay Chan

Gypsum is the common name for calcium sulfate, a very water-soluble form of calcium. If you want to add that, then apply gypsum.

What's your PH?

Thanks for the explanation. I needed to add calcium into the soil. That was the reason why I used gypsum, and I did that last week.

The pH in that part of the soil is acceptable according to the soil test recommendation sheet that I received from a soil test center. I don't remember exactly what the pH value is. If you want, I can look for it when I get back home.

The soil test recommendation sheet asked me not to do anything on changing the pH. Instead, it asked me to add calcium sulfate into the soil to increase the calcium level (because the calcium level is low).

Next year, I will use some cheap soil test kit to monitor the pH value of the soil. Sending out to soil test lab that can get expensive; I can only do that every couple years.

Jay Chan

That leads me to a another question. Are there differences in brands of soil tests? Are the ones you buy and send away, different than sending soil to your closest cooperative extension people?

Bonnie in NJ