The Homeowners Column

The Homeowners Column

Moss – space invader or space filler?

Photo of Sandra Mason

Sandra Mason
State Master Gardener Coordinator

If I were a leprechaun I would doze away the summer on a bed of pillowy soft moss. Its lustrous early green is also a welcome respite from the greys and browns of winter. I know not everyone shares my love of moss since I often get questions about how to kill it. Methods of moss's demise stem from massive misunderstanding. Questioners are concerned moss may be killing their grass or sucking the life from a tree; therefore, it's time to debunk some moss myths.

First of all moss is a space filler not a space invader. Moss is not a good competitor for space. Basically moss seeks a nice (often shady and moist) place to hang out that is not occupied by some other life form. Any open soil areas or tree branches are candidates. Moss on tree trunks doesn't hurt anything. It often grows on the shady, north side of the tree. Just enjoy the colors of moss or lichens decorating the trees. I call it "tree bling".

Moss may also appear in lawns in shady locations, but in spring may appear in sunny spots. Moss thriving in lawns signals that grass is weak and has thinned for some other reason, allowing space for moss to grow. The bottom line is moss is not really a lawn problem and some would say not a problem at all. UI Extension website offers these suggestions to improve lawn growth.

First figure out why the grass is not growing and remedy the problem. In addition to excessive shade, other causes of grass thinning and moss appearance, include compacted soils, poorly drained soils, and low soil fertility. Poor lawn care practices such as general lack of care, including irregular mowing and little or no fertilizer applications are common problems leading to poor turf growth.

Adding limestone is a common "remedy" mentioned for moss control, but is not suggested unless a soil test has shown the pH needs to be raised. Soil that is too acidic for lawn growth and therefore promotes moss growth is seldom a problem here in central Illinois. Adding limestone without a soil test can also add to the problem.

Save your money by not buying moss killing products for the lawn and instead concentrate on improving the health of the lawn grass. Raking out moss is another option; followed by reseeding with an appropriate grass seed. April is a great time to seed grass in these bare areas.

Too much shade for acceptable grass growth is common. Evaluate the site to assure the grass mix being planted is correct for the site conditions. In excessively shady areas (those that receive less than 4 hours of sun daily) ground covers or moss may be a better choice than turfgrass.

Take a good look at the soil conditions. Modify site conditions to favor lawn grasses. Reduce soil compaction by core aerifying. This may also help correct drainage problems; although serious drainage problems may require more extensive work to correct.

Evaluate lawn care procedures, especially fertilizing, and adapt to the conditions, such as shade. Mow higher (near 3 inches), and fertilize less in shade, as too much nitrogen can be detrimental to shade lawn species. About 1 to 2 pounds of actual nitrogen per 1,000 square feet per growing season is all that is needed. Reduce traffic over lawns in the shade.

Mow on a regular basis (based on rate of lawn growth) to avoid removing more than one-third of the leaf blade at any one mowing. Also avoid excessive watering. Water deeply and as infrequently as possible, based on lawn needs.

Or embrace your mossy side with moss gardening. A great reference book is Moss Gardening: Including Lichens, Liverworts, and Other Miniatures by George Schenk.

View Article Archive >>