Moss infestation of Piedmont lawns is a common problem. Moss invasions can occur for a variety of reasons, among them excessive shading; low soil fertility; soil compaction; high soil pH; and excessively wet soils. To diagnose moss problems first look at the variety of turfgrass selected for the site and be sure it is a shade tolerant variety. A mix of Kentucky Bluegrass, Tall and fine Fescue is among the best shade tolerant turf selections for our area. For a complete listing of shade tolerate turfgrasses for the Piedmont see NC Cooperative Extension Publication AG69, Carolina Lawns.
Have your soil tested to insure it is at the optimum pH for good turf growth and fertilize in accordance with the soil test recommendations. Proper fertilization of turfgrass can also help discourage weed growth. Judicious pruning of landscape trees can allow additional sunlight to reach the turf and can help alleviate moss problems. Be advised that some areas may simply be too shady to cultivate turfgrasses successfully. In these areas, use mulch instead or plant shade loving ground covers. Avoid excessive watering which creates favorable conditions for moss growth. Soil compaction can be addressed by the periodic use of a core-type aerator. Core aeration can also dislodge moss and make it easier to collect and remove from the site. Regular springtime dethatching operations using a flail type dethatcher can also dislodge up to 75% of moss.
Ferrous ammonium sulfate or ferric sulfate (iron sulfate) can be used to control moss, however unless the growing conditions are addressed the effect will only be temporary. The same goes for raking or otherwise manually removing moss and then reseeding. The key to getting a moss infestation under control is to change the conditions in ways that discourage moss and encourage healthy turf.
For more information contact Randy Fulk, Stokes Cooperative Extension at 336-593-8179 or by email at email@example.com.