Earth Science 25 Lb. 5,000 Sq.Ft. Coverage Fast Acting Gypsum Is A High-Quality Product That Repairs Crusty Soil and Loosens Clay Soils. Does not impact soil pH. It Also Repairs Winter Salt Damage And Dog Spots. Made from more-environementally friendly Flue Gas Desulfurized Gypsum as opposed to mined gypsum. Our Patented Nutri-Bond Technology Helps the product bond to the soil, holding Nutrients In Place For Maximum Effectiveness And Reduction Of Nutrient Runoff. One Application Lasts All Season Long.