Iron sulfate is a water-soluble form of iron that is often used as a supplement to correct iron deficiencies in plants. Iron is an essential micronutrient for plants, and it plays a crucial role in the production of chlorophyll. Chlorophyll is responsible for the green color in leaves through the process of photosynthesis.  

When plants lack sufficient iron, they can exhibit symptoms such as yellowing leaves, known as chlorosis. Iron Sulfate provides a readily available source of iron that can be quickly absorbed by plants to alleviate these deficiencies. 

Iron Sulfate can help lower soil pH levels, making it more acidic. This can be beneficial for acid-loving plants, such as azaleas, rhododendrons, and blueberries, as it creates a more suitable environment for their growth.