of Rhode Island GreenShare Factsheets
Mowing is the most basic and frequently practiced of all
lawn care operations. Proper mowing is essential in the maintenance
of quality turf.
Turfgrasses, like all green plants, must be able to photosynthesize
in order to survive and grow. Close mowing reduces the amount
of leaf area available for photosynthesis, reducing plant vigor.
As cutting height is reduced, lawns become less tolerant of
environmental stresses and more prone to invasion by weeds
than a lawn maintained at a higher cutting height. In addition,
root systems of grasses usually become shorter and less prolific
as cutting height is reduced. Although a closely-cut lawn can
be successfully maintained, its shorter root system will result
in a need for more frequent watering and fertilization to compensate
for its reduced ability to obtain water and nutrients from
the soil. It is therefore desirable to maintain your lawn at
the highest cutting height acceptable for its intended use
and aesthetic value. A cutting height of 5.0 to 7.5 cm (2 to
3 inches) is best for most lawns.
How fast a lawn grows determines how frequently it requires
mowing. In order to avoid stressing turf, no more than one
third of existing shoot growth should be removed at any one
mowing. For example, if a lawn is being mown at 5.0 cm (2 inches),
it should not be allowed to grow higher than 7.5 cm (3 inches)
before it is mown again. If a lawn grows excessively high for
some reason, the mowing height should be gradually reduced
to the proper height over a span of several mowings rather
than all at once. This will minimize excessive buildup of clippings
as well as prevent physiological shock to the plant which may
occur when the grass is severely defoliated after being allowed
to grow too high.
Unless an excessive amount of clippings remain on the
lawn following mowing (because of infrequent mowing), there
is no need to remove clippings by bagging or raking. In fact,
clippings are a valuable source of nutrients. Clippings returned
to a lawn will return nitrogen and other nutrients to your
lawn over the course of a season, thus reducing the need for
additional fertilization. The addition of organic matter in
the form of clippings may help to improve the status of your
soil over time as well, especially if it is sandy and/or low
in organic matter. Contrary to popular belief, returning clippings
to the lawn does not normally contribute to increased thatch
formation. Clippings are composed primarily of easily degradable
compounds which break down rapidly and do not accumulate. If
the lawn is mown when wet, clippings may clump together and
make removal necessary. Mowing when the lawn is dry will help
to prevent clumping; however, the lawn should not be allowed
to grow excessively high merely because the grass is wet. Mowing
a wet lawn (assuming no disease is active) will not damage
The direction of mowing should be varied with each mowing
in order to promote upright shoot growth. The formation of
a horizontal growth orientation (grain) can be minimized if
the lawn is mown at right angles on alternate mowings.
The two principal types of mowers available for use on
home lawns are reel mowers and rotary mowers. Reel mowers employ
a rotating cylinder of blades (usually five or six) which catch
the grass against a stationary bedknife in order to cut it.
While reel mowers provide the finest quality of cut available,
they are expensive, not easily adjusted by the homeowner, and
require specialized equipment for sharpening. Due to potential
damage to the cutting units, reel mowers also cannot be used
where stones, twigs or other debris are a problem. Reel mowers
are generally restricted to fine turf areas such as golf courses
and high maintenance athletic fields. Rotary mowers, which
employ a single blade that rotates horizontally, are by far
the most commonly used mower for home lawns. Rotary mowers
cut the grass by impact (similar to how a machete works), causing
a rougher, more uneven cut than a reel mower. However, they
will do an acceptable job on virtually any lawn and are much
easier to maintain than reel mowers. Mulching mowers are rotary
mowers which cut the clippings into small pieces. This allows
the clippings to fall down into the turf canopy more easily
and to decompose more quickly. It is very important to keep
the mower blades as sharp as possible, regardless of which
type of mower is chosen. Dull mowers tear the grass blades
rather than cut them, resulting in excessive injury to the
plants as well as a brownish cast to the turf.
Adapted from the University
of Massachusetts Extension, 2000
are poisonous! Read and follow all safety precautions on labels.
Handle carefully and store in original containers out of reach
of children, pets or livestock. Dispose of empty containers
immediately, in a safe manner and place. Pesticides should never
be stored with foods or in areas where people eat.
When trade names are used for identification, no product endorsement
is implied, nor is discrimination intended against similar materials.
Be sure that the pesticide you intend to use is registered for
the state of use.
The user of this information assumes all risk for personal injury
or property damage.
information, call the URI CE Gardening and Food Safety Hotline
at 1-800-448-1011 or (401)874-2929 from outside Rhode Island;
Monday-Thursday between 9 am and 2 pm.
of Rhode Island Cooperative Extension provides equal program