Moss is a common problem in many home landscapes. The home gardener may spend many hours and a great deal of money in an attempt to control it. The results are few if the cultural conditions that favor moss are not understood. Cultural conditions favorable for moss growth include one or more of the following: insufficient sunlight due to shade, an acid or sour soil (low pH), low soil fertility, a heavy or compacted soil or soil conditions that are too wet.
In the home lawn, the usual cause of moss growth is insufficient sunlight to support the turf grass. When the shade is due to trees or shrubs, it may be possible to increase sunlight to the turf grass by pruning and/or removing some of the plants. For more information on how to deal with shade, request bulletin 81-6, Lawn and Shade: Problems and Corrective Measures, from Agricultural Publications, 1376 Storrs Road, The University of Connecticut, Storrs, CT 062269-4035.
Acid soil conditions (low pH) are often blamed for the presence of moss. Many gardeners will make rather heavy annual applications of limestone in an attempt to kill it. If conditions are favorable, i.e., heavy shade and/or moist-to-wet soil, moss will grow quite nicely on limestone. Have the soil tested before applying limestone. Submit a soil sample, to one cup, to the Soil Testing Lab, U-102, Storrs, CT 06269-1102. There is a $2.00 charge for the service.
Soil with low fertility levels will not produce a vigorous turf. Weak, thin turf will provide niches for plants with lower nutrient demand to become established. Mosses have a low demand for nutrients. A soil test will determine the levels of the major nutrients. The soil test report will suggest amounts of nutrients to apply to correct any shortcomings which could have prevented good lawn/turf grass growth.
Heavy or compacted soil, as well as excessively wet soil, will have low oxygen levels. Oxygen is necessary for good turf grass root growth. Compacted soils can be aerated with a spoon or core-type aerator. Heavy soils (soils with a high clay or silt content) have a tendency to become compacted and waterlogged. An improvement in texture and aeration can be made by tilling a few inches of coarse, sharp sand into the existing soil A few inches of decomposed organic matter will also help. Where the clay content of the soil is high, tilling in 100 pounds of calcium sulfate (gypsum, land plaster) per 1,000 square feet could aid in improving the structure of the soil. Well-structured soil is usually well aerated.
Where the soil is wet for long periods of time due to a high water table or a shallow hardpan layer, it may be necessary to drain the offending water or grow plants suitable to the site. The installation of drain tiles and/or curtain drains should only be done by persons knowledgeable in their installation and familiar with the legal requirements.
Rough bluegrass, Poa trivalis, can be planted in wet sites because of its tolerance to wet and shaded sites.
Moss can be eradicated by mechanical or chemical methods. Raking with an iron rake or scraping will remove the moss. An application of one of the moss control products which contain potassium salts of fatty acids (DeMoss*) or iron sulfate found in commercially available moss control products will give short-term control of moss.
Killing the moss and failing to correct cultural conditions that favored moss growth will only result in its reinvasion. If it is impossible to correct the conditions, consider keeping the moss as a permanent low maintenance groundcover or plant another groundcover, pachysandra, English ivy or myrtle, which are shade tolerant.
The information in this material is for educational purposes. The recommendations contained are based on the best available knowledge at the time of printing. Any reference to commercial products, trade or brand names is for information only, and no endorsement or approval is intended. The Cooperative Extension system does not guarantee or warrant the standard of any product referenced or imply approval of the product to the exclusion of others which also may be available.All agrochemicals/pesticides listed are registered for suggested uses in accordance with federal and Connecticut state laws and regulations as of the date of printing. If the information does not agree with current labeling, follow the label instructions. The label is the law.Warning! Agrochemicals/pesticides are dangerous. Read and follow all instructions and safety precautions on labels. Carefully handle and store agrochemicals/pesticides in originally labeled containers immediately in a safe manner and place. Contact the Connecticut Department of Environmental Protection for current regulations.The user of this information assumes all risks for personal injury or property damage.Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Kirklyn M. Kerr, Director, Cooperative Extension System, The University of Connecticut, Storrs. The Connecticut Cooperative Extension System offers its programs to persons regardless of race, color, national origin, sex, age or disability and is an equal opportunity employer