By Clint Waltz
Georgia Extension Service
Volume XXVII
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In your yard, you may consider mowing a necessary evil. But
when you do it
right, mowing can be the single greatest contributor to a good-
looking lawn.
Mowing affects a turf’s density, texture, color and
uniformity. But few people
understand its real benefits. Even if you water and fertilize
your lawn correctly,
its overall quality is compromised if you don’t mow it
properly.
Mow for your grass type
Different turf grasses require different mowing heights.
Hybrid Bermuda grasses,
for instance, should be mowed every three to four days to keep
them at 0.5 to
1.5 inches high. Keeping the slower-growing centipede turf at
1 to 2 inches
requires mowing only every five to 10 days.
Other turfs’ best mowing heights and frequencies include:
- Zoysia, 0.75 to 2 inches, three to seven days.
- Common Bermuda, 1 to 2 inches, five to seven
days. - Tall Fescue, 2 to 3 inches, five to seven
days. - St. Augustine, 2 to 3 inches, five to seven
days.
Mowing heights and frequencies can change, of course,
depending on fertilization
and soil moisture. But mowing at the wrong height can harm the
turf’s rooting,
which in turn affects how the shoots grow and take up
water.
Mowing carefully decreases disease and
other problems, too
Weeds and diseases are more likely, too, if you cut the grass
too high or,
more commonly, too low. Cut at the proper height, a turf
grass’s canopy can
reduce the light penetrating to the soil, making it harder for
weed seeds to
germinate.
Improper mowing can make a lawn less tolerant of stresses
like temperature
extremes and traffic, too. No question about it: for a healthy
lawn, use the
correct mowing height.
Time mowing properly
Mow the lawn with a sharp blade when the grass is dry. This
spreads the clippings
better and keeps down diseases. Mowing wet turf causes clumps
of clipped grass
to remain on the lawn, which limits sunlight from reaching the
leaf blades.
The resulting yellow spots can be pretty ugly.
Mowing when the soil is too wet can also compact the soil
more and can slow
the grass’s rooting.
Mulching v. bagging
You may wonder whether you should bag your lawn clippings. If
you mow it properly,
leaving the clippings is a good idea. In fact, there are
several advantages
to leaving the clippings.
For one thing, clippings build up the soil organic matter,
which makes it easier
for water to move into the soil and helps the soil retain
water and nutrients.
There’s no evidence that returning clippings to the turf can
help build up
harmful thatch. Soil microbes efficiently break down the
clippings into organic
matter. And the decomposition process can reduce nitrogen
needs by 25 percent.
Don’t let clippings blow into storm water systems or surface
waters, though.
This can clog systems and pollute water sources. If the
clippings need to be
bagged, try composting and using them as a soil conditioner or
mulch.
Follow the ‘one-third’ rule
Decide when to mow based on the “one-third rule.” Never
remove more than one-third
of the leaf tissue at any one mowing. Removing more than that
or cutting the
turf too low can lead to a weak turf stand, decreased rooting
and a host of
other preventable problems.
A good guide is to mow the turf when it is 50 percent taller
than the desired
height. For example, if your turf should be maintained at 2
inches high, mow
it when it reaches 3 inches.
Letting the grass overgrow the “one-third rule” hurts the
turf. But mowing
too often is harmful, too. Mowing too often can allow diseases
to enter the
leaf tips more easily. Other negatives include increased wear,
soil compaction,
labor expense and wear-and-tear on mowing equipment.
