Learning Center / Lawn problems
Why is moss growing in your lawn?
Moss doesn't push grass out. It moves into spots where grass is already struggling: heavy shade, compacted or wet soil, and low fertility. Fix the conditions and the grass can take the space back.
- By David Obeid, founder
- Reviewed
- 4 min read
The short answer
What causes moss in a lawn?
Moss is a sign of conditions that are bad for grass and fine for moss: too much shade, soil that stays damp, compaction and poor fertility. Acidic soil can play a part too.
Killing the moss without changing those conditions just leaves bare soil, and the moss comes back.
The fix
How do you get rid of moss for good?
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Let in more light
Thinning low tree branches is often the single biggest help. Grass needs several hours of light a day.
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Relieve compaction
Fall core aeration opens up hard, wet clay so water drains and roots can grow.
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Test the soil
If the soil is acidic, lime helps the grass compete. More on soil tests and lime.
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Feed the lawn
Underfed grass is thin grass. A regular feeding program keeps it dense.
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Rake it out and reseed in fall
Rake out the moss, then overseed in early fall so grass fills the space instead of more moss.
Being honest
What if grass just won't grow there?
Some spots are too shady or too wet for any lawn grass, no matter what you do. Under dense trees or along a damp north-facing wall, reseeding every year is a losing battle.
In those spots, a mulched bed or a shade-loving ground cover is usually the better long-term answer, and it looks better than thin grass. What grass grows in shade.
Related questions
What people also ask
Does moss kill grass?
Not directly. Moss fills in where grass is already weak. Improve the conditions and the grass can take the space back.
Will lime get rid of moss?
Only if acidic soil is part of the problem, and even then shade, compaction and wet soil usually matter more. Test the soil before adding lime.
Keep reading
More from the Learning Center
- How do you get rid of lawn weeds and keep them out? Pre-emergent versus post-emergent, why crabgrass timing follows soil temperature, and why a thick lawn is the best weed control there is. Lawn problems · 6 min read
- How can you tell if your lawn is compacted? The warning signs of compacted clay soil, why it happens so often in Northern Virginia, and what actually fixes it. Lawn problems · 4 min read
- Should you renovate your lawn with sod or fix it with treatments? How to tell whether your lawn needs new sod or can be brought back with seeding and a lawn program, what each costs, and how long each takes. Lawn problems · 6 min read
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