Moss in grass

Asked May 3, 2019, 9:37 AM EDT

I have a pretty heavy moss infestation in my lawn and it's getting worse and not better. I live in a very shaded yard/subdivision with probably below average air flow too. The soils are clayey - glacial till. How can I treat moss in my lawn and/or who can I talk to?

Hennepin County Minnesota

1 Response

Full shade is a challenge. It would be good to know more about the tree coverage and if there are large roots on the surface in the shady area in question but I appreciate the information about clay soil. Moss invading lawns is common especially locations where the grass is growing poorly.
Moss growth is associated with

-excessive shade
-compacted soils,
-poorly drained soils,
-low soil fertility,
-abnormal acidity (usually too acid)
-lack of nutrients for grass.

You would do well start with a soil test that will tell you the nutrients and acidity of your lawn and give you guidelines for remedying them.

Moss grows well in wet soils and clay retains moisture. If the moss is growing in a low-lying area where the soil stays wet, improving the drainage can discourage moss from growing. Avoid watering on an automatic or regular schedule. This can encourage excess moisture and wet soils. Water your lawn only when you need to.

Grass does not grow well in compacted soils because of the lack of air, water, and nutrients moving through the soil to the roots. Soil compaction also prevents good drainage allowing a favorable spot for moss to grow instead of grass. Soil compaction can be alleviated by aerification. Aeration is the removal of cores of soil from the lawn. Many landscape/lawn businesses can aerate a lawn or aerators can be rented at many places.

Read more at:
This is some information on moss in the lawn.

Fine fescue is the preferred grass for shade and it take much longer to establish but is a thinner grass. Unfortunately turf grass in shade, if you can get it to grow, will never be as full as in the sun and aeration or other soil work will not change the shade conditions, so you are wise to consider other options.

Consider an alternative ground cover like Vinca Minor (Creeping Myrtle or Periwinkle), is tough, tolerant of many soil types, and will spread easily. It is great for pollinators. It needs water for the first year but once established it is very low maintenance. It is compact and mat-forming, with shallow roots that will not interfere with the tree roots and also has a nice spring flower. It is easy to find at garden centers.