I have a very heavy clay soil in my backyard. I want to add gypsum to loosen it up. How much do I spread on it?
How Much Gypsum for Clay Lawn
Certified GKH Gardening Expert
The use of gypsum on residential lawns is not recommended due to the cost and side effect reasons outlined in this article:
It is instead recommended to incorporate compost into your soil instead as it provides nutrition, water holding capacity and improved soil structure - and is much cheaper.
However, if you do want to pursue applying gypsum, you should follow the directions on your bag of gypsum. If there are no directions printed on the bag, the home depot has a chart on their website that will tell you how much gypsum to broadcast based on square footage: