Potassium is needed to complete many essential functions in plants, such as activating enzyme reactions, synthesizing proteins, forming starch and sugars, and regulating water flow in cells and leaves. Often, concentrations of K in soil are too low to support healthy plant growth. Potassium sulfate is an excellent source of K nutrition for plants. The K portion of the K2SO4 is no different from other common potash fertilizers. However, it also supplies a valuable source of S, which protein synthesis and enzyme function require. Like K, S can also be too deficient for adequate plant growth.