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University
of Rhode Island GreenShare Factsheets
General
Lawn Maintenance & Renovation
A
healthy established lawn is able to out-compete many weeds and
withstand a certain amount of pressure from disease and insect
attack as well as drought. You can maintain a healthy lawn with
proper fertilizing, liming, watering and mowing techniques. Fertilizer
applications should be based on soil tests. Research has shown
that a fertilizer with percentages of nitrogen, phosphorus (P2O5)
and potassium (K2O) in the ratio of 3-1-2
or 4-1-2 is the most efficient (least wasteful of any nutrients)
for the established lawn. If such fertilizers are not available,
a general purpose fertilizer (such as 10-10-10) can be used.
No more than 3 to 4 lbs. of actual nitrogen (total amount of
nitrogen actually in the fertilizer) should be applied to 1000
square feet of most lawns in a given year. Less may be used if
clippings are left on the lawn. Excess nitrogen promotes lush,
tender growth susceptible to disease, resulting in higher maintenance
needs. Fertilizing at the wrong time of year can also lead to
problems. For
the best lawn appearance, we generally recommend three applications
of 1 lb. of N per 1000 square feet. The first application should
be in the early spring, perhaps as late as Mother's Day (timing
isn't critical unless you are using a fertilizer/herbicide combination--which
we generally do not recommend). A second application around Labor
Day will get the lawn growing again for the fall, and a third
application around Thanksgiving will keep roots growing through
the winter and result in early spring greenup. If you want to
use less fertilizer, try applications 1 and 3 or just the first.
Older, established lawns may need only one application, or perhaps
fertilizer applications on less than an annual basis. Several
variables, including type of nitrogen (quick or slow-release),
desired use and condition of turf and number and timing of fertilizer
applications determine a fertilizing program. The fact sheet Developing
a Fertility Program for Lawns provides a more complete discussion
of lawn fertilizing. Calibrate
your spreader to apply the proper amount of fertilizer. Do
not apply fertilizer when grass leaves are wet. Water the lawn
immediately after fertilizing to wash the fertilizer off the
foliage and to prevent 'burning' the plants (unless the directions
on the bag state otherwise). Ground
limestone may be applied at any time of year, though late summer
to early fall is best. No waiting period is generally necessary
between liming and fertilizing. Most soils in Rhode Island are
slightly acidic and can benefit from a general maintenance application
of lime--usually 40 lbs. per 1000 square feet, but a soil pH
test tells you exactly how much you need. Unless your soil is
really acidic, a lime application every few years should be adequate.
See GreenShare Factsheet on soil testing for
more information on how test your soil. Unless
watered regularly, a well-established lawn may naturally go into
a dormant 'brown' period during the hot summer months. The lawn
is not dead and will become green again in the fall when conditions
are cooler and damper, unless the drought is pro-longed. However,
allowing the lawn to go dormant may mask insect and disease problems--dead
areas may be evident when greening does occur. If you water during
the summer, do so regularly using the following guidelines: • Water
your lawn slowly and thoroughly, enough to wet to a depth of
4 to 6 inches. One inch of water (or rainfall) every week is
probably sufficient, or you can let the grass be your guide.
Light, frequent waterings are undesirable because they encourage
shallow root systems. • When
the blades turn a dry, bluish green, the edges of the blades
curl or a 'foot print' is left after walking, it is past the
time to water--water as soon as possible • Watering
is best done in early morning to reduce waste and to reduce the
chance of disease (foliage which is wet all night is more subject
to disease). For
additional information on watering, see GreenShare Factsheet: Efficient
Watering of Turf A
rule of thumb is to keep the lawn at a height of about two to
three inches. Mow frequently enough that you do not remove more
than one third of the leaf blade at one time. The lawn may be
cut as low as 1-1/2 inches in the spring and fall, but it is
best not to cut below 2 inches in the heat of the summer. During
the summer, the lawn may even be left a little longer, 2-1/2
to 3 inches. Fescues and shady grasses are grown a little longer
than bluegrass. There is a direct relationship between grass
length and rooting depth, so grass kept too short is less able
to withstand drought and stress. Too close a cut will make the
lawn more susceptible to weed and insect problems as well. It
is not necessary to remove clippings from a lawn if it is mowed
frequently. Do not let the lawn grow very high and then cut it
back all at once; this can be a shock to the grass plants and
can severely weaken them. This will also require the removal
of the clippings so that they do not smother the lawn. If the
lawn has become very long, shorten it gradually with a series
of successively closer mowings. Use a sharp mower; the cut should
be clean with no shredding or tearing of the plants. Do not mow
or work on a lawn when it is frozen or very muddy. These practices
can damage a lawn. For
additional information on mowing, see GreenShare Factsheet: Mowing. Weeds
can best be held at a tolerable level by maintaining a dense,
healthy lawn. If weeds become a problem, use an effective herbicide
registered for their control. Hand weeding may also be a solution
in some cases; be sure to remove the root system of the weed
as well as its top growth. Diseases
are most likely to occur in lawns suffering from inadequate soil
aeration or drainage, overwatering and/or improper fertilizing
or mowing. Fungicides are rarely recommended for the home lawn,
since proper maintenance is usually sufficient to keep disease
problems to a minimum. Injury from other causes--burning with
fertilizers or herbicides, dog damage, insect damage or drought--may
be mistaken for disease symptoms. Insects such as the Japanese
beetle and other grubs (rooteaters), chinch
bugs (which suck plant juices), ants (which disturb soil
by mounding) and other pests are common. A healthy lawn is able
to survive light infestations, but severe insect problems may
need to be dealt with by appropriate use of the proper insecticides. Lawns
sometimes deteriorate over a period of years to the point where
they cannot be nurtured back to an acceptable level of quality
using standard cultural practices such as fertilizing, proper
watering, etc. The lawn may be in poor condition because improper
grasses were used initially or have become "out of balance." Overuse,
neglect, extensive thatch accumulation, disease, insect and/or
mechanical damage or a heavy infestation of weeds are other reasons
to renovate. Under circumstances such as these, renovation of
the lawn may be necessary. Renovation consists of eliminating
whatever factors cause poor quality, followed by reseeding without
completely tilling under the lawn. The process of renovating
may be as basic as simply reseeding bare spots, or as involved
as killing all vegetation using a nonselective herbicide such
as glyphosate (Roundup or Kleenup), followed by reseeding the
entire lawn. Renovation
during late summer (August 15 - September 15) generally yields
the best results. Minimal weed competition as well as cooler
temperatures and ample rainfall usually follow late summer renovation,
thus providing a favorable environment for new seedlings. Late
summer seeding must be accomplished early enough to allow the
grass to become well established before the onset of cold weather
in order to enhance winter survival. Renovation may be attempted
during spring if absolutely necessary. As timing approaches late
spring, however, extensive weed competition coupled with summer
drought and heat stress reduce the probability of success. The
following procedure is designed for renovation of large areas
of turf and/or entire lawns. If only a few small spots require
reseeding, steps 2 and 3 may be omitted. 1.
Correct whatever factors caused the lawn to deteriorate to the
point of needing renovation. Re-contour the lawn if necessary,
improve drainage, eliminate excessive shade, etc. Renovation
will only yield temporary improvement unless the original cause
of poor quality is remedied. 2.
Control all weeds present. Most broadleaf weeds can be selectively
eliminated by using glyphosate (Roundup). Small infestations
of bunch-type (non-spreading) weedy grasses can be removed by
digging. Remove the weed, grass and soil to a depth of about
2 to 3 inches. Remove soil for a distance of about 2 to 3 inches
outside of the clump to ensure the removal of all the undesirable
plant. Perennial
weeds which spread via rhizomes (underground creeping stems)
or stolons (aboveground runners) cannot be controlled by digging.
Spreading perennial grasses such as quackgrass and bentgrass
should be controlled using a nonselective herbicide such as glyphosate
(Roundup or Kleenup). It may be advisable to permit the lawn
to grow slightly higher than normal prior to weed control to
allow the weeds to grow larger, thus producing more leaf area
for better herbicide uptake and control. Wait 10 to 14 days following
herbicide application before proceeding with renovation in order
to allow for complete herbicide uptake and allow any chemical
residues in the soil to dissipate. Always follow label recommendations
when using herbicides. Specific information concerning rate of
application, weeds controlled, and waiting period before reseeding
is stated on the label. 3.
Mow the entire area as low as possible (1/2 to 3/4 inch) and
remove all debris. If there is an appreciable accumulation of
thatch (more than 1/2 inch), remove it at this time using a dethatcher
(sometimes called a power rake or vertical mower). A dethatcher
is a power-driven machine similar to a lawn mower, but with a
series of vertical blades or tines which rotate on a horizontal
shaft to remove surface debris and thatch. Several passes over
the area may be needed to achieve desired results. Remove all
debris created by this operation. See GreenShare Factsheet on thatch for
more information. 4.
Cultivate the soil in order to assure good seed-to-soil contact.
This is an important step, since seed broadcast onto a lawn without
proper cultivation will not survive. Cultivate using a dethatcher
set to penetrate the soil to a depth of about 1/4 inch, exposing
enough soil to provide a good seedbed for establishment. On small
areas, a garden rake can be used to loosen soil to the proper
depth. 5.
Fertilize and lime (if necessary). Incorporate the materials
into the soil at this time. Proper soil fertility and pH are
essential for successful renovation. Base application rates of
these materials on soil test results.
Obtain a soil test three to four weeks prior to renovation, if
possible. If soil test recommendations are unavailable, approximately
2 lbs. of phosphorus and potassium per 1000 sq. feet and approximately
1 lb. of nitrogen per 1000 sq. feet should be worked into the
soil to promote seedling growth. "Starter" fertilizers which
contain substantial phosphorous can be purchased for this purpose. 6.
Following cultivation and fertilizer application, the lawn is
ready to be seeded. Seed of a species similar to that existing
in the lawn should be used unless improper species selection
was the original cause of poor quality. Seed should be applied
uniformly over the area to be renovated. Use a seeding rate for
a new lawn if glyphosate was used on the entire area, or 1/2
rate if 50% of turf is still present. In order to insure uniform
coverage, apply the seed in two directions made at right angles
to each other. Enough seed should be applied to provide 15 to
25 seeds per square inch. For larger areas, consider renting
a powered slit seeder. 7.
Rake lightly following seeding (a leaf rake works well), or drag
with a steel mat or door mat to work the seed into the soil to
a depth of about 1/4 inch. The area should then be rolled to
ensure good seed-to-soil contact. If the area being renovated
is on a slope, apply a weed-free mulch to prevent erosion. 8.
Water lightly and frequently, two to three times per day to keep
the seed bed damp during the period of germination and establishment.
The duration of germination and establishment will vary among
grass species but will probably range from four to six weeks,
with perennial ryegrass being the fastest species to establish
and Kentucky bluegrass the slowest. Continue to mow the lawn
on a regular basis during renovation. 9.
Apply a balanced fertilizer to provide 1/2 to 1 lb. of nitrogen
per 1000 sq. feet when seedlings are about 2 inches high. This
will enhance growth and hasten the recovery of the lawn to the
quality you desire. Adapted
from the University of Massachusetts, 1999
Pesticides
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.
For more
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.
University
of Rhode Island Cooperative Extension provides equal program
opportunities.
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