Q: I have an area in my lawn where moss is growing under the grass. What can I do to get rid of the moss?

• John, Canfield

Q: John, the moss is growing under your turf grass because the conditions in that part of your yard are favorable for moss and less favorable for the grass. Moss grows in moist, shaded areas. Turf grass, on the other hand, doesn’t like shaded or wet conditions.

Moss is a very old type of plant. Mosses do not have a vascular system or roots. Instead, moss absorbs the water and nutrients it needs directly from the air.

Moss and similar plants like liverworts and hornworts collectively are known as bryophytes. They reproduce by spores instead of seeds.

Bryophytes play a very important role in the environment: they colonize sterile soils, absorb nutrients and water and release them slowly back into the ecosystem, contributing to the formation of soil for new plants to grow on.

Moss cannot outcompete turf grass when conditions are favorable for the grass. The key is to find out why the grass isn’t thriving there. Once the conditions are changed to suit the grass, the grass will take over from the moss.

As mentioned, moss likes shade and moisture (where the area stays damp). Other conditions that favor moss are low soil pH (acidic soil) and soil compaction. Grass prefers sunlight, adequate water (but not damp conditions), moderate soil pH and loose soil.

To begin, I would suggest doing a laboratory soil fertility test for your lawn. A lab soil test will tell you the pH of the soil, its organic content and nutrient levels.

If you are not familiar with soil tests, the OSU Mahoning County Extension Office can help you with soil testing. When you have your soil test report you can start amending the area’s soil based on the report’s recommendations. This will help make the area better for growing grass.

If the soil is compacted, you can aerate the area and add compost to loosen the soil. If trees or shrubs are shading the area, you can prune them to let in more sunlight. If drainage is an issue, adding compost will help clay soil drain better. And changing the slope of the area may be needed to get rid of any excess water.

There are chemical controls for moss, but they are not recommended.

Another option is to not have grass in that area and instead plant shade-loving plants. With the shade plants in place, any moss would just be a natural part of the area.

If you keep the grass, the best defense against the moss is a healthy lawn. Regular mowing (to a height of 3 inches), watering and proper fertilizing will give the grass the best chance to remain healthy and keep the moss away.

Thank you for your question.

For more information on moss in lawns, visit canr.msu.edu/news/tips-to-toss-the-moss-from-your-lawn

For more information on moss, visit stri.si.edu/story/bryophytes

Sprague is an Ohio State University Extension Master Gardener Volunteer in Mahoning County.