Moss can be a decorative ground cover when it grows where it's wanted, or it can be considered a nuisance weed when its thick mat of tiny green leaves and threadlike stems are unwanted. Though moss won't kill your grass, it can leave your lawn looking splotchy and uneven. Luckily, there are a few solutions to manage moss.
Ways to Kill Moss on Your Lawn
Traditional ways of eliminating moss include spreading iron sulfate moss killer. You can also get rid of moss in your lawn by making it less acidic by adding lime to the soil. Or, you can use good old sweat equity and rake out the living moss from your lawn. But the simplest, safest method is to use dish soap. It's easy to learn how to kill moss with this recipe that costs pennies to whip up. Just follow these three steps.
For small patches, mix in a garden hand sprayer 2 ounces of dish soap and 1 gallon of water. Use gentle liquid dish soap, such as blue Dawn, which you'll find in most grocery stores. For larger areas, use 4 ounces of dish soap in 2 gallons of water for every 1,000 square feet of lawn.
Spray the mixture on the patches of moss. Holding the spray nozzle a couple of inches from the target area, drench the moss with the solution. Make sure not to spray the grass, as the solution can also kill healthy grass.
The patches of moss will turn orange or brown in 24 hours and eventually dry up. Dig up the dead moss. The dish detergent does not necessarily kill moss at the roots, so remove as much of the moss as possible. The surrounding grass will begin to grow over the patches.
After raking up the dead moss, take it to an isolated area. Don't compost it or the moss spores could spread back into your lawn. Wait to re-seed bare areas left by the dead moss, as the liquid soap can impede germination. Top the new grass seed with new, loose soil that's free of moss spores.
When to Apply the Moss Killer Solution
Late spring or early fall are the best times to kill lawn moss. Killing moss should always be done before seeding your lawn, which is best done in the early fall.
Always apply the dish detergent and water mixture when the grass is moist. also, check the weather to make sure there's no call for rain in the forecast within 24 hours of application.
Avoid using the dish liquid and water method for moss that appears on your roof. Moss on your roof needs to be quickly, but gently, removed with commercial preparations so your roof tiles remain undamaged.
Discouraging Lawn Moss Growth
If more moss appears in your lawn, it's safe to repeat the dish detergent treatment. Treatments like this are temporary, however. The underlying cause of moss growth needs to be addressed to control its growth. That usually means testing the pH level of your soil. Moss likes acidic soil, so increase your soil's pH by adding lime, also called dolomitic lime. Lime makes your soil less acidic by adding more alkaline.
Though lawn lime adds nutrients to existing grass to encourage its growth, it won't directly kill moss. Lime can be added to your lawn between fall and early spring. Or, lime your yard before fall's first frost to give your soil all winter to absorb the lime.
Adding lime isn't a guarantee that you'll never see another patch of moss. If the moss seems impossible to eradicate, especially if it's growing in a perpetually shady area, let it flourish. Consider venturing into moss gardening. You might even develop a love of running barefoot on your lawn and over those velvety patches of moss.
Controlling Moss and Algae in Turf. UGA Cooperative Extension
Managing Moss. University of Oregon Extension