Hi-Yield Fast Acting Gypsum is a highly efficient method for breaking up dense soil, surpassing standard gypsum. It's our choice to repair heavy clay soils, and also salt damaged soil. Fast Acting Gypsum quickly improves soil structure; allowing better air and water penetration and promoting better root development and growth with calcium and sulfur. Also reduces soil loss. Use on lawns, vegetable gardens, flower gardens and ornamental beds. Apply any time of year, but spring and fall are best. Pelletized for clean and easy application. 20 lb. bag. New lawn coverage: 20 lbs. per 2,000 sq. ft. Established lawns: 20 lbs. per 4,000 sq. ft. Shrubs: 1 cup at base. Vegetable and flower gardens: 1 lb. per 100 sq. ft. Always read and follow package directions.