Copperas is Iron Sulfate or Ferrous Sulfate Heptahydrate and is a quick release form of soluble iron that has long been used in agriculture as a treatment for iron chlorosis in plants. It is widely used as a lawn conditioner and turf enhancer. It can also be dug into composts or soils for longer lasting effects. In Florida’s calcareous soils, Copperas is an excellent tool to relieve iron chlorosis in crops such as sugarcane, citrus and blueberries.

Copperas can be solubilized with water and sprayed which will give it a more immediate effect. In a Turf grass quality and nutrition study, liquid copperas was one the very few products found to have a positive effect on turf quality 100% of the time.
Turf Grass Nutrition: Iron, Manganese, and Magnesium. By Shaddox, PHD, Unruh PHD, Kruse, PHD.