If your lawn is overly wet or shaded, any open patches in the grass can become covered in moss. Though the carpet-like green growths are not as invasive as the typical weed, moss can be an eyesore and compete with your grass for space and soil nutrients. Change the environment of your lawn to deter the growths and kill off any present moss to restore the health and beauty of your lawn.
Prune back nearby shrubs and overhanging tree brances to increase sunlight on your lawn. Also, reduce watering as much as possible as appropriate for your lawn species. Mosses thrive in shaded, moist environments. Drying out your lawn can help kill it and prevent new growths.
Aerate your lawn with a handheld aerator or a mechanical aerator. This further helps dry out the soil to kill moss. Additionally, moss tends to be attracted to dense, compact soil, and aerating the soil deters the plants from appearing or spreading.
Kill the moss with an herbicide formulated with ferrous or copper sulfate and intended for use on lawns for moss control. This quickly eliminates the growths. Apply according to the herbicide's label, as toxicity varies by brand. Typically, you'll mix 3 oz. of the sulfates with several gallons of water and spray it across your lawn, focusing on areas with moss.
Rake away the dead moss and discard.
Plant grass in the areas that once had moss immediately after removing the growths. This helps prevent moss from returning. Sow with grass seed or add sod or grass plugs.