Earth Science Fast Acting Sulfur® starts working immediately to naturally lower the pH of your soil. Acid-loving plants require a low pH soil environment to thrive (between 4.0 and 5.5). Most other plants perform best when soil pH is between 6.2 and 7.2. When used as directed, Fast Acting Sulfur® helps your plants absorb more food and improves fertilizer effectiveness for a lush green lawn and colorful garden.