Hi Yield Ammonium Sulfate Fertilizer is a high-nitrogen fertilizer that also provides sulfur to help acidify soils. Ideal for alkaline soils and high-pH areas, it is suitable for trees, shrubs, flowers, and vegetables. Apply ½ pound per 100 sq. ft. for gardens, and one 16 lb bag covers up to 3,200 sq. ft. of lawn. Always water generously after application for best results.