Moss
Control
By: Sandy Feather
©2006
Penn State
Cooperative Extension
Q: What do
you recommend to control moss in a lawn? I have used a product
called Scott's Moss Control and have applied limestone with little
or no success.
A:
Moss can be difficult to control. It is important to find and
correct the underlying factors that have created such a favorable
environment for the moss or else it will grow back quickly, as you
have found. Correcting those problems will allow the grass to
outcompete the moss. Conditions that favor the growth of moss
include excessive moisture, heavy shade, compacted soil, poor soil
fertility and low soil pH.
Start by having
your soil tested. Test kits available from your county extension
office come with instructions for taking a good representative
sample. Do separate tests for lawns, flowerbeds and/or vegetable
gardens. If you have lawn areas that are very different -- one
heavily shaded by mature trees vs. an open lawn in full sun -- have
them tested separately. The results should come back in 10 to 14
days and will tell you exactly how much limestone and fertilizer to
apply to correct the soil pH and improve soil fertility. To order a
kit from the Penn State Extension of Allegheny County, see the end
of this column.
If the area
stays constantly moist, it will be very difficult to get ahead of
the moss. You may need to install French drains to move water away
from the area, redirect downspouts or take other steps to improve
drainage. If improving drainage requires re-grading the area, be
very careful around existing trees. A few inches of additional soil
over a tree's root system can cause it to decline and may kill it
completely. Roots cannot get sufficient oxygen if they are buried
under too much soil.
If the area
stays moist because of dense shade from mature trees, consider
hiring a certified arborist to remove some of the lower limbs and
thin dense canopies. Allowing more sun exposure and increasing air
circulation will help the area dry faster after rainfall. Also, more
sun will create a better environment for grass to grow. Even
shade-tolerant varieties do best with some sun.
You can
alleviate mild soil compaction with
core aeration prior to applying
limestone and fertilizer as recommended by your soil test. A core
aerator is a machine that pulls out plugs of soil 3 to 4 inches
long. The holes left behind promote better soil aerification. Better
soil aerification creates a more favorable environment for the
development of a strong root system for the grass. Also, some of the
limestone and fertilizer will filter down into those holes,
affecting the change in soil pH and fertility where the grass roots
live.
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Type of Lawn Grass
Finally, the
species of turfgrass is important because most do not perform well
in shade. Fine fescues do well in shady, well-drained areas. Rough
bluegrass (Poa trivialis) tolerates shady, moist areas. Be
aware that rough bluegrass has a floppy growth habit and is not the
most attractive lawn grass. But it will grow where no other grass
species will survive. Neither species will survive long term in
extremely dense shade or constantly saturated soil.
Once you have
addressed the underlying causes that permitted the moss to get the
upper hand, then you can use a product registered to eliminate moss.
Scott's Moss Control, DeMoss from Mycogen Corp. and LESCO Moss and
Algae Eraser are chemical controls
registered in Pennsylvania to
eliminate moss. Be sure to read and follow label directions. If used
improperly, both products can "burn" desirable turfgrasses.
You might also
consider taking the path of least resistance and create a moss
garden in your back yard. You obviously have ideal conditions for
moss to grow. You can purchase different types of moss at garden
centers and through mail-order catalogs. A woodland garden planted
with native wildflowers, mosses and woody plants such as mountain
laurel and rhododendrons may be more appropriate for the conditions
in your yard than turfgrass. It is usually easier and cheaper to
choose plants that fit your site than it is to change the site to
fit certain plants.
Fertilizing
a lawn
Liming soil
More of
Sandy's Lawn Tips
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