John Orick
, Purdue Master Gardener State Coordinator Department of Horticulture and Landscape Architecture
Mosses are small plants
that look like a mass of fine stems that grow in a variety of conditions
ranging from very wet to dry soils. They vary in size and are without a root
system, but grow root-like filaments which attach to the soil or other
substratum. Mosses can invade lawns with low fertility, poor drainage, heavy
shade, soil compaction, poor air circulation, or a combination of these
factors. Moss infestations in lawns are not caused by low soil pH. Under poor growing
conditions as previously described, moss plants are able to out compete
turfgrass and infest lawns thinned due to these poor growing conditions. Mosses
are not harmful but many homeowners desire a thicker stand of turf vs. moss in
their lawns.
The only permanent way to control moss in turf areas is to correct poor
growing conditions causing the moss to out compete turfgrasses. The following
lawn maintenance practices will help control moss infestations:
· Fertilize lawns at least once per year. Late- August through
November is the prime time to fertilize turf for recovery from summer stress
and to maintain a dense, green, deeply rooted turf with optimum energy reserves
for future growth.
· Improve drainage. Some moss species thrive in wet conditions. Poor
drainage can be sometimes be corrected by improving the surface grade of the
soil but other drainage issues will require the installation of a tile drain.
· Increase air circulation. Areas surrounded by trees
may block air circulation over the turf. Pruning tree limbs or removing plants
when feasible, may help increase air movement over turf plants and help dry the
soil surface.
· Provide more light. Growing turf in dense shade can be very challenging
and this situation often forces the homeowner to choose between growing turf or
trees. When practical, remove trees or prune tree limbs to provide more light
to turf. In many cases and when soil drainage is adequate, homeowners may
choose to grow an alternative ornamental plant like a shade-loving groundcover,
perennial or annual flowers suitable for dense shade.
· Aerify or cultivate compacted soil. Many moss species are
adapted to compacted soil conditions but turfgrass plants are not. Therefore,
cultivating the soil through use of a hollow-tine core aerifier or a power rake
can help loosen the soil and relieve compaction.
· Seed areas to reestablish turf. Seed shade-adapted species
under shade trees in thinned lawns. Use fine fescue species such as creeping
red fescue, Chewings fescue, and hard fescue under shade trees in lawns in the
northern 2/3 of Indiana. Use tall fescue in the southern 1/3 of Indiana. Late
summer and early fall seeding dates have the best chance of establishing
because it will provide the longest exposure to direct light during the fall
before the tree’s deciduous foliage returns the next spring.
Publications and Related Websites:
Fertilizing Established
Lawns (AY-22-W) https://www.extension.purdue.edu/extmedia/AY/AY-22-W.pdf
Establishing Turfgrass Areas
From Seed (AY-3-W) https://www.extension.purdue.edu/extmedia/AY/AY-3-W.pdf
Improving Lawns in the Shade (AY-14) https://www.extension.purdue.edu/extmedia/AY/AY-14-W.pdf
Mowing, Dethatching,
Aerifying, and Rolling Turf (AY-8-W) https://www.extension.purdue.edu/extmedia/AY/AY-8-W.pdf
Controlling Moss and Algae
in Lawns, Turf Tip, 4/4/03 by Zac Reicher. https://turf.purdue.edu/tips/2003/moss44.htm