How often and when should you apply liquid gypsum?
How often and when should you apply liquid gypsum?
By Joe, Founder of Dr Forest · June 2026
How often and when should you apply liquid gypsum?
For clay soil, apply every two weeks for the first three months, then monthly. For lawns, monthly through the growing season from March to October. Begin a clay programme in early spring or autumn, when the soil is moist and workable, rather than in the middle of a dry spell or a hard frost.
The heavier early run on clay is there to get calcium through the top of the profile, after which a monthly drench keeps it topped up. On lawns the same logic applies: a fortnightly start on heavy clay, easing to monthly once drainage picks up. For general feeding of pots, borders and vegetables, a drench every two to four weeks through the season is plenty. There is no need to apply in the depths of winter, when growth has stopped and the soil is cold or frozen. As with most things in the garden, steady and moderate beats heavy and occasional, and you do not gain anything by exceeding the rates.
From the Dr Forest range
Liquid Gypsum: micronised calcium and sulphur
19.55% calcium and 15.31% sulphur, milled to 5 microns and handcrafted in Stockport. A calcium and sulphur feed that does not change soil pH.
See rates and sizes★★★★★ 5-star across all platforms · 3,250 reviews · See the Liquid Gypsum page.