Moss grows in shade, moisture

Q. How can I get rid of the moss on my roof?

Susan from Canfield

Q. How can I get rid of green moss on my lava rock and the side of my house?

Denise from Campbell

A. Moss is a sign of intense shade and high moisture. Thus, improving air circulation in the affected area or increasing sunlight exposure may lead the way to reduce the amount of moss. Most of us notice high levels of moss in the spring because this is its peak time of year in our climate.

On a roof, homeowners should trim any limbs or trees touching the roof area. Even low-hanging limbs should be removed, not only to improve air circulation, but to prevent other damage limbs can cause. Be sure leaves and other items are removed from the roof promptly. Do not try controls such as salt or other suggestions, as they can cause even more damage to structures. Control on the side of a house or other area would be treated the same – increase air circulation and sunlight exposure.

In lawn areas, moss is most likely a sign of lack of lawn management. If lawns are properly managed, moss will not compete. To improve your lawn, do a soil test to check the pH and fertility levels. The day after a rain, check for puddles which will be a sign on poor drainage. If grass is thin in shady areas, you may need to select a grass species that grows well in the shade. If pets thin out areas of your grass, consider changes to that area. Check mowing height. If the lawn looks scalped, increase the mowing height.

Raking moss out of lawns will help reduce competition, but is not completely effective.

Moss control is not easy. Cultural practices will start to reduce the problem, but may not address it completely. Our friends at Virginia Tech suggest, “Some other environmentally friendly options that have been demonstrated to show activity [but not necessarily control] on moss include lemon-scented liquid dish detergent in a 3-percent solution [e.g. 1 ounce dish detergent per quart of water]. Put your soap solution in a squirt bottle and periodically apply it through the mister. Also, light dustings of baking soda will quickly brown moss, but rarely will it kill the plant.” (Complete details are available by downloading their fact sheet listed below.)

Commercial moss-control products are available for the roof, house and lawn. If the products contain iron, beware they will stain siding, sidewalks and other surfaces around the home. Products containing copper and zinc will work on roof surfaces and other parts of the home, but they can also affect desired plants and turf. Be sure to read and follow all label directions before purchasing the product, and before using.

For more information visit, and

Eric Barrett is OSU Ext. educator for agriculture and natural resources in Mahoning County. Call the office hotline at 330-533-5538 from 9 a.m. to noon Mondays and Thursdays to submit your questions.

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