Calcium sulfate is widely used by California growers, but it is very likely under-used in many cases. Considering the range of benefits it has to offer in so many of California’s regions and growing conditions, farmers may find it worthwhile to do testing that focuses on sulfur and calcium, particularly with regards to calcium’s effect on soil chemistry and soil structure.

Effective calcium sulfate options include both dihydrate gypsum and anhydrite gypsum. Despite misconceptions about the solubility of anhydrite gypsum, both materials yield the same benefits, and both dissolve readily enough for practical applications. Anhydrite gypsum is the more concentrated version of calcium sulfate. Gypsum is a fast-release material, anhydrite gypsum a slower-release product which stays in the root zone longer making it available for plant uptake.

The true cost of any particular calcium sulfate application may, ultimately, depend on its shipping cost. It can nly be determined by calculating the quantity of a particular product that will be needed to meet the gypsum
equivalent dosage, and then figuring the cost of material plus shipping and spreading. It is worth doing the calculation to find the best source and reap the many benefits of calcium sulfate.