Perform a soil test to determine your soil type and mineral constitution. If the test reveals that you have clay soil or too much sodium, magnesium or aluminum, then the soil can benefit from a gypsum application.
Add gypsum granules to a fertilizer spreader and spread it on your grass at a ratio of 40 to 60 lb. per 1,000 square feet; you can spread it by hand if you have a small lawn. Repeat this application once per year.
Till garden and flower bed plots and then spread 20 to 30 lb. gypsum granules per 1,000 square feet of soil to prepare the soil for planting. A lawn spreader will also work for this type of gypsum application.
Spread gypsum on the soil surface around plants at a ratio of 40 lb. per 1,000 square feet; spread by hand for small gardens or use a fertilizer spreader for larger applications. Repeat the application annually for up to three years.
Water the gypsum liberally immediately after spreading it to help it start dissolving into the soil.
Add more or less gypsum in a single application and apply it more frequently at your discretion, depending on the extent of compaction and clay in your soil.