(Oneida County, NY – April 2013) Moss growth normally starts with fall rains and reaches a peak in early spring. Because most grasses grow poorly in winter, mosses are able to invade and often dominate lawns in only a few months.
Moss growth declines in summer as conditions become drier and turf grass growth increases, but under shady, irrigated conditions moss may grow through summer. Moss can tolerate long periods of drought in a dehydrated condition and rehydrate and grow with the onset of fall rains.
Cultural Control: Although moss will invade well-maintained lawns, it usually occurs extensively in neglected lawns where cultural conditions enable it to out-compete turf.
Moss encroachment generally is associated with
- Thin turf
- Low fertility
- Improper pH level (do not apply fertilizer until you have your pH tested)
- Shade
- Wet soils
- Turf injury from insects, diseases, chemicals, or cultural practices.
Long-term moss control is impossible unless these conditions are corrected!
Often turf is thin because it lacks fertilizer. Properly timed nitrogen fertilizer applications will increase turf density, vigor, and competitiveness. Maintaining the soil pH to between 6.0 and 6.5 will benefit some grasses in the long run but will have no direct effect on moss. Grasses grow poorly in dense shade because of low light and increased disease activity.
Therefore, shady lawns usually have more moss than lawns in full sun. Thinning out trees by selective pruning or removing trees completely may reduce moss encroachment. In some cases, it’s easier to redesign the area and eliminate turf than it is to improve lighting. When planting new lawns in shady sites, be careful to select shade-tolerant species. In relatively dry shade, the fine fescues perform well. In wet, shady sites, rough stalk bluegrass persists better than other grasses.
Thin turf, caused by injury, is a common contributor to moss encroachment. Un-irrigated lawns turn brown and thin out during summer. When fall rains come, these lawns may not recover fast enough to compete with moss.
Severe dethatching in fall also may predispose the lawn to moss because turf is thin when fall rains come. Proper culture, which promotes healthy, dense turf during the moss season, reduces moss encroachment in most situations.
Mechanical Control: Moss can be removed by dethatching in early spring. Optimum timing is mid-March through April, when moss is still healthy and vigorous. After dethatching, have your soil pH tested. The result of your pH test will determine what your next course of action will be.
Master Gardener Volunteers are available to answer your gardening questions Wednesday and Friday from 9-Noon. Call 736-3394. pH Soil Testing is also available, samples can be dropped off between 8AM-4:30PM at the Cornell Cooperative Extension Oneida County, 121 Second St. Oriskany NY 13424. Complete Soil Analysis Testing Kits may also be obtained at the office or you may visit this website http://goo.gl/CFYgm