Dealing with Shady Sites
Dealing with Moss Problems
Significant moss may signal problems such as excess shade or poor soil
drainage.
Moss invading lawns is a common problem typical in shady locations. Other causes of moss invasions, in addition to excessive shade, include compacted soils, poorly drained soils, low soil fertility, high or low soil pH, and poor air circulation. Moss thriving in lawns signals that grass is weak and has thinned for some reason, allowing the moss to take over. Poor lawn care practices are another source of moss problems. 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. Many soils in northern Illinois tend to have high pH values; adding limestone will make this pH go even higher, adding to the lawn problem. Ferrous ammonium sulfate or ferric sulfate (iron sulfate) can be used to control moss to some extent. The moss will temporarily burn away, but tends to return fairly quickly. Raking out moss is another option; usually followed by reseeding.
Modifying site conditions to favor lawn grasses and discourage moss is a suggested way to manage the problem. Too much shade for acceptable grass growth is a common underlying cause for moss invasion. Pruning trees and shrubs to improve air circulation and light penetration is a good starting point. Evaluate the site to assure the proper grass for the conditions is being used.
Take a good look at the soil conditions. A soil test can be helpful, as it could be the soil pH is out of line, contributing to the problem. 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, as mentioned earlier. Lawns need adequate fertility, in particular nitrogen, but less in shade. Excessively short mowing may be a source of the moss problem; a range of two to three inches is ideal for most lawn grasses. Mow on a regular basis (based on rate of lawn growth) to avoid removing more than one-third of the leaf blade. Also avoid excessive watering, as this may contribute to moss problems. Water deeply and as infrequently as possible, based on lawn needs
