Moss can take hold in places where grass is not thriving, usually because of excessive shade, poor drainage or overwatering. It’s easiest to simply leave the moss as a trouble-free ground cover, but if you can’t live with it, try these solutions.
Remove lawn moss with elbow grease
If the moss isn't too extensive, it can be removed manually in early spring. Use a dethatching rake or a mechanical dethatcher available from rental agencies. After this procedure, stimulate grass growth and density with organic fertilizer, a topdressing of weed-free compost and a locally appropriate grass seed.
- Let the sun shine in. Remove lower limbs from trees and shrubs to limit shady areas.
- Promote good drainage. Aerate compacted soil with a sod-coring tool or a spading fork, and topdress with weed-free compost. In extreme cases, subsurface drainage like French drains or leachfields may be necessary.
- Overseed your lawn. Sprinkle a locally appropriate lawn seed mix over your lawn to help out-compete moss. Apply about 25 percent of the sowing recommendation for a new lawn.
- Improve the soil in spring or fall. Topdress by spreading a quarter- to half-inch layer of compost that's free of weed seeds. If a soil test indicates a need, add an organic or slow-release lawn fertilizer. Grasscycling – leaving the clippings on the lawn – can reduce fertilizer needs by 50 percent or more. If a soil test indicates the pH is low (meaning it is acidic), add ground limestone or oystershell lime along with the topdressing of weed-free compost.
- Don't over-water. Just one inch of water (from all sources, including rain) per week is enough.
Replace lawn with shade-loving ground covers
If you have a shady yard, you may want to try more maintenance-free groundcovers. Native plants that may be useful include Fragaria vesca (woods strawberry), Oxalis oregano (redwood sorrel), or Maianthemum dilatatum (false lily of the valley).
Chemical methods are only temporary
Two chemical treatments that will temporarily kill moss in lawns are iron sulfate and potassium soap salts. While both are allowable by national organic standards, they can cause severe skin and eye irritation, and soap salts are also highly toxic to aquatic invertebrates. With either chemical, care is necessary to avoid runoff into storm drains or surface water. These chemicals are short-lived fixes, and still require elbow grease to rake out the dead moss. Unless lawn conditions are improved, the moss will come back.
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