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Michael Wheeler: Tips for controlling moss and algae in turfgrass
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The primitive plants of moss and algae begin to form as turfgrass areas begin to thin out. This happens because conditions for growing dense, healthy turf have declined.

Neither moss nor algae are thought to be parasitic, but both can form crusts on the soil surface which reduces air and water movement. And both are spread by windblown spores.

Moss is a branched, threadlike green plant that forms a tangled, thick mat over the soil. Algae is a thread-like green plant that form a dense, green scum over the soil surface. 

Factors favoring their development include wet and humid conditions as well as compacted soils with thin turf. Moss is more common in shady areas with infertile, acidic soils and excessive thatch. Algae prefers full-sun conditions and fertile soils.

Cultural practices favoring turfgrass growth will reduce the competition from moss and algae. These practices include the following:


Have the soil tested to determine the proper lime and fertilizer needs. For most turfgrasses, the pH should be 6.0-6.5.


Contour wet soil areas to allow the water to drain. In some cases, tile drainage may be necessary to correct wet conditions.


Pruning tree limbs below 10 feet and selected limbs in the crown will improve light penetration and air movement. Removing some of the least desirable trees and thinning and/or removing shrubs will help. Areas surrounded by buildings and vegetation with limbs close to the ground may require considerable work to provide adequate air circulation and light penetration.


Use a turf type of tall fescue grass. However, if direct sunlight does not reach the ground during the day for at least six hours, an ornamental ground cover may be better suited to the site.


Aerification with a machine that removes plugs of soil will help reduce compaction. Core aerifiers may be rented, purchased or contracted through lawn service companies. Drainage in fine textured soils can be improved by cultivation and adding large amounts of organic matter.


Avoid light, frequent irrigations. Wait for signs of moisture stress such as the development of a bluish-gray, dull color before irrigating.

Irrigate to wet the soil to at least 6 inches. Most healthy turfgrasses need about 1 inch of water per week during active growth.

If puddling occurs, stop irrigating and wait two to three hours for the water to soak into the soil before watering again.


Generally, turf may be renovated if covers less than 50 percent of the landscape. Then re-establishment will be needed.

Soil test, till and fertilize based on results when renovating the lawn.

Overseeding may be an option to thicken the lawn if it is less than ideal, but not so bad you can justify a complete renovation.

Michael Wheeler is county extension coordinator for the UGA Cooperative Extension office in Hall County. You can contact him at 770-535-8293, His column appears biweekly and on

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