Turf - More on Moss Control

Moss is a common weed in shaded lawns and golf course putting greens. Persistent moss is a sign of an environment that is unfavorable for turfgrass growth. The following is more information on moss and control of moss.

Conditions favoring moss include acid soils, poor drainage and excessive wetness, shade (moderate to heavy), low mower cutting height or turf “scalping” and compaction. Mosses are primitive plants with over 13,000 species. Some mosses require constant moisture, others are well adapted to drying out and then regrowing when moisture is available. Carpet type mosses that survive dessication are the most troublesome for control. An example is Silvery Thread Moss (Bryum argenteum).

Moss control starts with correcting the underlying problems that restrict turf growth (improve drainage, remove shade, lime to raise pH, raise mower height). Chemical controls will suppress moss but will not totally eradicate it and include Quicksilver (carfentrazone) herbicide, Junction fungicide (copper hydroxide plus mancozeb – for golf course use only), and spring applications of Daconil Ultrex fungicide (chlorothalonil). Ferrous sulfate can suppress moss; nitrogen fertilization with ammonium sulfate has provided some moss control; and hydrated lime can suppress moss (some phytotoxicity). Soaps and salts can also be effective. Research has shown that Dawn Ultra dishwashing soap (10 ounces of Dawn Ultra in 2.5 gallons of water) is an effective spot application on moss. Baking soda has also worked as a spot application (6 ounces / gallon of water). Another option is TerraCyte (sodium carbonate peroxyhydrate), a granular product that is applied in the spring or fall. Finally, fatty acid based products (many brands) have provided some control.

In areas where moss grows better than turf, consider converting the area into moss gardens. You can find information about moss gardens at http://www.ext.vt.edu/pubs/turf/430-536/430-536.html.

Gordon Johnson, Extension Horticulture Agent, UD, Kent County