Acid-loving plants like azaleas, rhododendrons, hydrangeas, and blueberries will experience improved color, hardiness and disease resistance in proper soil pH. Most fertilizers don't affect soil pH enough for these plants. Ready-to-use Bonide Soil Acidifier is a powerful sulfur source that will correct deficiencies in the soil. With its convenient shaker top, it is easy to use. Sprinkle evenly beneath plants or work into new beds. Apply spring and fall. (2.5# bottle)