Espoma Organic soil acidifier is the perfect blend for acid-loving plants like Hydrangeas and Blueberries!100% natural and organic ingredients approved for organic gardening which is highly effective and safe.How To UseApply in Spring and every 60 days until desired ph levels and desired bloom colors are achieved.For Hydrangeas & Blueberries: Use in the spring to lower soil pH. New Plants: 1-1/4 cups per plant. Established Plants: 2-1/2 cups per plant Spread evenly around the base out to the drip line and water well.For potted plants use one tbsp. for each 4″ of pot diameter.Apply 1/2 cup per 100 sq. ft (1 tablespoon per plant) around the base of the plant.Broadcast Rate: Apply 12 lbs. per 100 sq. ft. for each one-point reduction in soil pH desired. For heavy clay soils increase the rate to 15 lbs. A gradual reduction in soil pH is preferred as dramatic reduction can result in stress.*Safer than Aluminum Sulfate due to potentially toxic levels of Aluminum with continued use of Aluminum Sulfate.