Mowing practices greatly determine the quality of
lawns. Allowing a lawn to grow too tall and then cutting it short is
stressful to grass. It uses a tremendous amount of its stored energy
reserves to push out new growth after such treatment. The general
rule of thumb is not to remove more than one-third of the leaf blade
at one time. Rather than mowing on a schedule – say, every Saturday
– mow as the grass’s growth dictates. That may be twice a week
during the cooler weather in spring and fall, or every few weeks
during hot, dry summer weather (especially if you do not water).
Proper Mowing Height
Most species of turfgrass should be cut at a height
of two-and-a-half to three inches. There is a direct relationship
between the height of cut and the depth and extent of the root
system. The longer the grass grows, the more extensive its root
system; the shorter you cut it, the less root system it will have.
Summer heat and drought are more stressful for our cool-season grass
species than winter cold. Keeping the grass a little taller
encourages an extensive root system that will make your lawn more
drought-tolerant. It also shades the soil, moderating soil
temperatures and helping to conserve soil moisture as well as
shading out germinating weed seeds that try to become established.
Lawn care company applicator
Be sure to sharpen your mower blade regularly. A
sharp mower blade makes a clean cut that the grass recovers from
easily. Dull mower blades shred the grass, making jagged wounds that
are harder to heal. They can serve as a point of entry for insect
and disease problems. How often you sharpen your mower blade depends
on the size of your lawn and the number of obstacles it is likely to
encounter. Monthly sharpening for large lawns is not unreasonable;
smaller lawns can get by with once a year.
Important is Proper Fertilization
Next to proper mowing, appropriate fertilization is
important to encourage a dense, well-rooted stand of lawn grass able
to resist pests and environmental stress. Inadequate or excessive
fertilization can make the lawn more susceptible to disease and
insect problems and less tolerant of summer stress.
A soil test will help you design a fertilization
program that provides what your lawn needs for optimum health
and growth. It will also tell you what you have to do to get your
soil pH (acidity or alkalinity) into the optimum range of 6.5 to 7.0
that most lawn grasses prefer. Soil test kits are available from
your local Penn State Extension office for a nominal fee. In
Allegheny County, consumer soil test kits cost $12 each, and come
with detailed instructions for taking a good soil sample and
information to help you understand your soil test results. Customers
ordering multiple kits at one time pay $9 each for the additional
kits. Send a check made payable to Penn State Extension to Penn
State Extension, 400 North Lexington Street, Pittsburgh, PA 15208.
Write Attn. Soil Test Kit in the lower left corner of the envelope.
Typically, late spring (mid- to late May), late
summer (late August to mid-September) and late fall (mid-November)
are the best times to apply fertilizer. Fertilizing in late spring
supports the increased root and shoot growth typical in spring,
while the late summer-early fall application helps the lawn recover
from summer stress and supports increased root and shoot growth that
will return with cooler weather and rain. Once the grass is no
longer pushing top growth, but before the ground freezes, it is time
for the final application. This last application supports root
growth that will continue until soil temperatures fall below 40
degrees. All fertilizer applications should be made when there is
adequate soil moisture. Since plants take up nutrients in water,
there is no point in applying fertilizer to bone dry soil.
Uneven application resulted in "skunk stripes"
Liming is best done in fall. Limestone moves through
the soil very slowly and takes time to effect the desired change in
pH. If your soil test reveals that your lawn needs 100 pounds or
more of limestone per thousand square feet, break it into two
applications, fall and spring.
Watering your lawn when we get into hot, dry summer
weather is a personal choice. It is fine to allow your lawn to go
dormant. An otherwise healthy lawn can go about six weeks without
rain; it will turn brown, but should recover when cooler
temperatures and rain return. If you choose to water, make sure you
do so properly in order for the lawn to benefit from it as much as
Established lawns benefit most from
deep, infrequent watering that encourages a deeper, more extensive root system.
Conversely, frequent, shallow watering encourages a shallow root
system. A shallow root system means a lawn that is under drought
stress when the top inch of soil dries out. Use a sprinkler or an
irrigation system to apply one inch of water weekly to your lawn
when rain is minimal. This is best applied in one long, deep soaking
session, rather than watering your lawn a little bit every day. Our
clay soils can only absorb about one-half an inch of water an hour,
so it should take two hours of watering to apply an inch of water.
To determine how long you have to run your sprinkler or irrigation
system, take a flat-bottomed container such as a coffee can and mark
off half-inch increments. Place the can or cans where it will be hit
by the water, and time how long it takes to gather one-half inch of
water. Then run your sprinkler twice as long. You may need to apply
water even slower to steep slopes to avoid wasting water to runoff.
When to Water
It is best to water in the morning. If you water
during the heat of the day, too much water is lost to evaporation.
If you water at night, the grass stays wet too long, which can
result in more disease problems.
can become Serious
You should also check your lawn for thatch. Older
lawns often suffer from a deep thatch layer. Thatch is nothing more
than a layer of organic matter between the soil surface and the
crowns of the grass plants. Dig up a small square of turf so you can
look at the soil profile. The thatch layer is easily visible. Thatch
is created when growing turfgrass sloughs off dead stems and roots.
A thin layer of thatch - one-half inch or less - is desirable. It
acts as a mulch, moderating soil temperature and maintaining soil
moisture. More than that creates problems, though. A thick layer of
thatch can keep water from reaching the soil, so your lawn is
constantly drought-stressed. And that creates more thatch. Thatch
can also be a breeding ground for insect and disease problems. Even
worse, if your lawn does develop a problem with white grubs (soil
dwelling-insects that feed on turf roots), a thick thatch layer can
make it very difficult to get an insecticide down to where the grubs
are feeding. The causes of thatch include:
The variety of grasses in your lawn. Bluegrass
and creeping red fescue are the worst thatch formers of the cool
season lawn grasses.
A soil pH
lower than 6.5 immobilizes the microbes that break down thatch.
Over-fertilizing your lawn.
grass to grow too tall, and then cutting it short and not
collecting the clippings.
layer of thatch - between one-half and one inch - can be removed by
dethatching your lawn with a power dethatcher. Dethatching is very
stressful and should only be done in fall. You can rent dethatchers,
or hire a lawn service to do it for you. Run the dethatcher in one
direction, and then go over you your lawn in the perpendicular
direction. A good dethatching job should make you want to cry when
you look at your lawn. Topdress the lawn with a thin layer
(one-eighth to one-quarter inch) of good compost, then overseed with
varieties of turfgrass that match your existing lawn to help it
Up to ˝-inch of thatch is OK
If you have
over one inch of thatch, consider a total renovation - removing your
existing lawn and starting over. The knives of most dethatchers will
not go deep enough to get through the thatch and down to the soil,
which is important for a good dethatching job. A good dethatching
job is a lot of hard work, but will not be very effective if you
have over an inch of thatch.
A Lawn Breathe
If you do not
have a thatch problem, but the soil is compacted, rent a
core aerator. Again, they are available from many tool rental shops, or
you can hire a lawn service to do the aerating for you. Core
aerators pull three to four inch plugs of soil out of the ground and
leave small holes behind. This helps aerate the soil and alleviate
soil compaction. Fall is ideal for core aeration (just before
applying limestone) but it can be done in the spring as well. If
your lawn does not have a lot of activity on it, core aeration every
three years or so will keep the soil aerated sufficiently. If all
the neighborhood kids play in your yard, consider yearly core
aeration in late fall to reduce soil compaction as much as possible.
You can break up the cores with a rake or allow them to stay on the
lawn where they will break up during winter’s freeze-thaw cycles. If
they are creating too much of a muddy mess (when children and/or
pets play on the lawn), you can rake them up and put them on the
Heavy thatch and grubs destroyed this home lawn
with compost after core aeration is a good tool to slowly improve
the quality of the soil under your lawn without tearing it up and
starting over. A lawn is only as good as the underlying soil. A six
to eight-inch base of topsoil that contains a moderate amount of
organic matter is ideal, but few lawns have that luxury.
As a matter of
fact, yearly topdressing with a thin layer of compost followed by
overseeding is one of the most important tools to maintaining a
healthy, attractive lawn without using pesticides. Keep a bag of
grass seed on hand so you can fill in bare spots whenever they occur
so that grass fills in, rather than weeds. Those spots will have to
be kept moist until the seed germinates and the grass fills in,
especially during hot summer months.