Lawn Moss Killer

Fungicide

• Fungicides containing potassium salts of fatty acids or iron sulfate kill lawn moss, according to the University of Connecticut. Other fungicide products with ferrous sulfate and ferrous ammonium sulfate are also recommended by Washington State University. Moss and algal soaps are also applied for moss control. Apply fungicides across their lawns on dry days to remove their moss. Reapply the fungicide according to the label's directions.

Dethatching

• Remove dead moss and excess thatch with a power dethatcher. Lawns with a layer of thatch more than ½ inch thick create a moist environment perfect for moss growth. By removing your thatch build up, more air and sunlight reach the grass, encouraging dense growth. Check the thatch layer by digging up a 2-inch wedge piece of the yard and measuring the brown, spongy material between the grass and soil. If there is less than 1/2 inch, rake up the dead moss. For a thick thatch layer, use a power dethatcher.

Fertilizing

• Fertilizing your yard is the ultimate moss killer. By encouraging grass to spread, moss can't take advantage of bare areas. Fertilize your lawn with 1 lb. of nitrogen for every 1,000 square feet at the beginning of its growing season. For cool-season grass, fertilize in fall. Fertilize warm-season grass in the early spring or when the grass comes out of dormancy. Give your lawn fertilizer every six weeks during the growing season.

Watering

• The more you water the lawn, the more moss you will see. Moss thrives in moist soil. Adding water to saturated soil increases the moss problem. Lawns need 1 inch of water a week. You can tell how much water your lawn has received for the week by placing tuna cans over the lawn. A tuna can is 2 inches tall. If the can is half full, you do not need to water the lawn.