Used predominately on warm season grasses or for alkaline soils, 21-0-0 Ammonium Sulfate is a great solution for quick green-up without burn potential. In the soil the ammonium ion is released and forms a small amount of acid, lowering the pH balance of the soil , while contributing essential nitrogen for plant growth. Landscape Supply's Ammonium Sulfate is slightly unique in the fact that the prill size allows the product to be spread on all different types of turfgrass or even melted down, very easily, and sprayed as a foliar nitrogen source. A very cost-effective solution for a quick green up without a lot of top growth.