Controlling moss in the lawn is an ongoing process. Killing the moss is the first priority. The second priority is to remove the environmental conditions that promote moss growth. By using iron sulphate, or ferrous sulphate, the homeowner can kill the moss. However, this is only the first step in controlling moss growth on the property. Providing good drainage, sun and air circulation is the second step necessary for the lawn to recover.
Rake as much moss as possible out of the lawn. Dispose of the moss in the trash or place on the compost pile.
Mix the iron sulphate with water according to the manufacturer's instructions. Pour into a hose-end sprayer. Attach the sprayer to the garden hose.
Spray the lawn with the iron sulphate mixture, wetting the moss thoroughly. Do not water in; allow the lawn to dry out after applying the iron sulphate.
Rake the lawn again to remove the dead moss, three to five days after spraying.
Over-seed the lawn with new grass seed. Sprinkle a light layer of compost or sand over the grass seed. Water thoroughly. Keep moist until the grass sprouts.
Prune overhanging trees and shrubbery to allow sun and air circulation in the affected area. Repair any drainage issues by adding soil to low spots or building a dry stream to carry away excess water. Most mosses prefer a shady, moist environment. Changing the environment discourages moss regrowth.
Vigilance is key to moss removal. Spray with an iron sulphate compound as often as necessary to kill the moss. Fertilise the lawn with a high-nitrogen fertiliser.
Wear gloves and safety glasses when raking, mixing the iron sulphate, spraying and pruning. Keep the solution out of reach of children and pets.