Why Use Ferrous Sulfate for Lawns?

Causes of Moss Growth

• Moss grows on lawns with excess surface moisture, poor drainage, low fertility, excessive shade and high acidity levels in soil. It proliferates during rainy weather and temperate winter seasons and generally does not grow during warm summer periods. Moss will not kill grass, however mossy growth on lawns creates unfavorable conditions that eventually lead to grass dying out, if left untreated. It will not grow in well-maintained lawns, as grass that is healthy and kept to a good standard will crowd it out.

Commercial Moss Killers

• Commercial moss killers contain ferrous sulfate and potassium, the two principal ingredients that will rid lawns of moss. Moss killers are available in granular or liquid form. Complete fertilizers with iron are available and will stimulate lawn growth and also remove moss. Iron or ferrous sulfate will stain patios and paintwork, so care should be taken when applying moss killers.

Rate of Application

• Ferrous sulfate should be applied at a rate of 0.5 to 1.5 pounds of iron per 1,000 square feet of lawn. Proprietary moss killer products have application levels on the label that should be followed for best results. Always use moss killers that are specified for lawns, as a moss killer for use on the roof can kill or damage your lawn.

How Ferrous Sulfate Works on Moss

• Applying ferrous sulfate to your lawn causes a reduction in moss growth. Ferrous sulfate may not kill the moss, but it may burn it and weaken it. In order to eliminate moss from the lawn entirely, it will need to be removed and the bare patch can then be sown with grass seed. If you are situated in temperate zones, applying a moss killer in late fall could help prevent the growth of moss during the winter.