Turn to Hi-Yield Iron Plus Soil Acidifier when your lawn, flowers, trees, shrubs or citrus trees are turning yellow from iron chlorosis. Iron Plus also treats stunted growth, poor flowering and fruiting, and reduced response to fertilization due to iron chlorosis. This fast-acting formula is designed not to burn when used as directed on the package label. Use to balance pH in alkaline and calcareous soils. Pelletized material. 4 lb. bag treats 400 sq. ft. of lawn and several trees or shrubs, depending on size and soil alkalinity. Always read and follow label directions.