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How does liquid gypsum work?

By Joe, Founder of Dr Forest · June 2026

How does liquid gypsum work?

Gypsum works by releasing calcium and sulphate as it dissolves. The calcium displaces sodium held on clay particles and raises the salt concentration of the soil water for a while, and both effects encourage dispersed clay to flocculate, meaning the fine plates clump into crumbs that let water through.

Dispersed clay is the problem behind a lot of capping and poor drainage. When the plate-like clay particles repel each other they spread out, block the pores between them and set into a dense skin as they dry. Calcium ions sit between those plates and let them gather into larger crumbs, and the brief rise in dissolved salts as the gypsum goes into solution helps the same thing along. The result is more space for air and water. Because our gypsum is milled to 5 microns, it dissolves within hours rather than over months, so the calcium is available to do this quickly.

This mechanism is real, but it is largely a story about dispersive and sodic clay. On clay that is not dispersive, there is little for the calcium to flocculate, so the same chemistry produces a much smaller structural change. That is the single most important thing to understand before you buy gypsum for a clay problem.