Moss - the other lawn weed

 Moss has been a problem weed for us over the last several years.  I think a lot of this results from the lack of competition from our cool season grasses like the fescues. Mosses are opportunistic plants that will grow where turfgrasses are thin and weak.  The hot dry weather has caused the fescues to stop growing, go dormant and over time has weakened the stand.  Moss will reproduce by means of wind-blown spores from one area to another and form the green mat on the soil surface that we recognize as moss.

The appearance of moss in a lawn can be associated with a number of other factors including problems with turfgrass management and/or soil and site characteristics. Mosses are small plants that can grow and out-compete turfgrass species when one or more of the following occur: high soil acidity (low soil pH), low soil fertility, heavy shade, poor soil drainage, soil compaction, shallow rocky soils and limited air movement.

            The first step in controlling moss in a lawn is to determine the nutritional status and pH of the soil so that fertilizer and lime applications can be made to correct any deficiencies. Heavy or compacted soils can be improved by incorporating several inches of sand and/or composted leaves or organic matter into the soil and by aeration. These amendments may help to improve both soil texture and drainage. Hand raking can be effective for eradicating moss. However, control may only be temporary if the reason(s) for the infestation is not fixed.

Moss can also be controlled through the use of chemicals. Since moss grows most strongly during cool moist conditions in the fall and spring, these are the best times for applying chemical moss killers. Chemicals and rates for controlling Moss can be found in the UT publication (PB956) “Managing Lawn Weeds: a Guide for the Home Owner” available at the UT Extension Office or downloaded from the internet.  Always consult the label for dosage rates and safety precautions.  Once the moss blackens and dies from the application, it may be raked and removed or used as a mulch for reseeding.