University of Minnesota Extension

Extension > Extension in your Community > Stearns > County Horticulture Educator > Articles > Moss in your Lawn

print icon email icon share icon

Moss in your Lawn

University of Minnesota Extension, Stearns County News
May 9, 2016        
Source:  Beth Berlin, Extension Educator-Horticulture
University of Minnesota Extension
Stearns & Benton Counties

Moss in your Lawn
By Beth Berlin, University of Minnesota Extension

ST. CLOUD, Minn. (05/04/16) — Have you noticed a lot of moss in your lawn this spring? Moss is sometimes evident in lawns, especially in spring, when conditions are wet and cool.  Moss can be challenging to control, but taking a closer look at what the true conditions are is the first step.

Several factors may contribute to moss, the first is moisture.  Even though this spring hasn’t been that wet, we have had a swing of cooler temperatures and some nice rain in late April after a warm March.  Having good drainage is important to reducing moss growth and encouraging turfgrass.  We cannot control temperatures or the amount of rain, but we can look at our soil compaction. Soil compaction contributes to drainage issues as well, so knowing when to avoid working in your lawns, and assisting with proper aeration can help create ideal conditions for healthy turf. 

Other issues related to the soil that contribute to moss in lawn are acidic soil.  Many people just assume they need lime on their lawn, but I would strongly recommend before applying lime to your yards that you have your soil tested to determine the pH level. The soil test will also give other nutrient input recommendations.

Another common issue causing moss in lawns is shade.  All turf grass varieties prefer sun, and areas of the yard that have shade due to building structures and/or tree cover will not provide enough sun for a strong, healthy turf to grow.  In many situations it may be best to discover other groundcover or plant material that prefers shady conditions.  There are numerous perennials and ground covers such as Hostas, Astilbe, Catmint, Lily of the Valley, and many more that would not only do well in the shady conditions but also eliminate any mowing.

The best way to discourage moss in the lawn is to have healthy, vigorous turfgrass.  Fertilize and water appropriately.  Water at an infrequent but more heavy rate to encourage deep root systems, fertilize in the late summer to early fall to encourage healthy growth, and mow at a higher height to also promote deeper root growth; this is typically a mowing height of 2.5 to 3.0 inches.  In shaded areas, consider properly pruning nearby trees and shrubs to provide more light penetration to the turf and more air circulation. Also use more shade tolerant grass varieties. A good mixture to try is 65% to 75% fine fescue; 25% to 35% Kentucky bluegrass (shade tolerant cultivars); ~10% perennial ryegrass.

Other mechanical efforts may need to be done yearly to improve drainage and decrease compaction such as power raking or aerating in heavy soils, ideally done in late summer to fall.  However simply raking the area with a heavy garden rake to scratch up the moss, and then cultivating the bare spots and reseeding with a grass seed mixture appropriate for the area is a great tip.  Moss will not crowd out turf once established but will spread where turf is not well established, so efforts must be made to make ideal conditions for the turf to grow and be healthy.

There are a few chemical options on the market; however none will eliminate the moss completely if the other site conditions such as light, moisture, compaction, and soil pH and nutrition haven’t been solved.  If you opt to use a product on the moss, be sure to read the directions and labels carefully for correct application and safety precautions.

  • © Regents of the University of Minnesota. All rights reserved. The University of Minnesota is an equal opportunity educator and employer.