|
back
| home
University
of Rhode Island GreenShare Factsheets
Installing
a Sod Lawn
The installation of sod is a popular way to establish
a new lawn. Most of the sod purchased is a blend of different
Kentucky bluegrass varieties or a mixture of other common turfgrass
types (i.e., fine fescue, perennial ryegrass, tall fescue).
When installed correctly on properly amended soil, in the appropriate
sunlight conditions and where correct maintenance is provided,
a sod lawn can be a valuable part of your landscape.
There can be many potential problems in installing a sod
lawn. Sod is often installed on top of soil that has had little
or no preparation, for example. Inadequate consideration is
often given to the sunlight requirements of each turfgrass
species. Many new lawn owners are misadvised as to the maintenance
requirements of Kentucky bluegrass as well--although Kentucky
bluegrass does require a certain level of maintenance to perform
at its best and to offer its best aesthetic qualities, it does
not require the wasteful practices we often see property owners
providing (i.e., exceeding recommended fertilizer rates and
frequency, frequent over watering, excessive use of pesticides
when problems don't exist, etc.).
With a little planning, preparation and correct maintenance
Kentucky bluegrass sod (and other types) can be an asset to
your property.
Site Considerations
Survey the site before selecting the grass type and/or varieties
that will dominate the sod you purchase. Most of the Kentucky
bluegrass varieties grow best in sites receiving full sunlight
all day. There are a few varieties that will tolerate moderate
amounts of shade. If the site is too shady you will need to consider
another type of grass for best results. See our GreenShare Factsheet
on Selection of Grasses for more
information.
Control Weeds
If obnoxious perennial and/or annual weeds exist on the site it is best to
consider controlling these (if possible) before the sod lawn is installed.
Correct Drainage Problems
Drainage problems need to be addressed before installing sod. If excess water
does not drain rapidly through the soil, the turfgrass will have a poor
root system and will grow weak. In some instances you may need to consider
installing a drainage system to move excess water from problem areas in
your yard to areas where the water will not cause a problem.
Grading
Be sure to grade the soil away from fixed points on your yard (i.e. your house,
the sidewalk, etc.). You should do this with gradual, gentle slopes so
that water will be directed away from your home and off your property.
Soil Improvement
The need to acquire topsoil is not a necessity when installing a sod lawn.
Often existing soil is suitable for sod or can be improved to make it suitable.
Have your soil tested for soil pH and nutrient levels (see GreenShare factsheet
on soil testing for information on submitting
soil samples for testing). The test results will direct you in how to improve
your existing soil. The soil pH should be between 6.0 and 7.0 for best
results. Limestone is used to increase the soil pH and should be mixed
with the top 6 inches of soil before the soil is final graded. This is
also the time to correct any nutrient deficiencies.
If you do not test the soil you
will have to rely on certain "rules
of thumb" in regard to additions of limestone and fertilizer.
Add 50 lbs. of dolomitic limestone per 1000 square feet. Starter
fertilizers in 1-2-1 or 3-4-1 ratios (i.e. 10-20-10 or 18-24-6)
should be added at the rate of 1 lb. of nitrogen per 1000 square
feet. The limestone and fertilizer should be mixed with the
top 6 inches of soil.
Most soils benefit from additions of organic matter. To
improve a sandy soil, work about 1-2 inches of organic matter
into the top 4-6 inches of soil. Another method is to thoroughly
mix 1 inch of heavier soil with the top 4 inches of sand. A
better alternative is to add both organic matter and heavier
soil rather than one or the other.
If a heavy or "clay-like" soil
needs improvement you should work organic matter into it.
Do not add sand into a
clay soil, since this will cause it to pack harder than before
much like concrete.
Organic matter sources vary. Consider using 4 large (6-cubic
foot) bales of peat or 2 to 3 cubic yards of well-rotted manure
or cultivated peat. Similar amounts of finished compost could
also be considered. These volumes should be evenly spread across
1000 square feet and mixed with the top 4-6 inches of soil.
Topsoil
If you decide to bring in topsoil you should plan on adding at least 4-6 inches
of good topsoil, even though it is expensive. You need to consider at least
this amount since a 6-inch layer of loose soil settles to about 5 inches.
Turfgrass roots will occupy approximately 5 or 6 inches of soil. If the
topsoil layer is too thin the turf may actually be growing in the pre-existing
soil. If possible plan ahead when purchasing topsoil. In this case you
will have adequate time to have the soil tested for pH, nutrients and physical
analysis.
Soil grade changes have the potential
to damage and kill existing trees on your property. If you
are going to add topsoil
over the roots of existing trees it is imperative that you
take the appropriate steps necessary to prevent damaging and
killing trees. A simple "well" constructed around the trunks
of trees is not sufficient. See our GreenShare Factsheet
on Protecting Trees during Construction for
more information.
Final Preparation
Sod should be installed on top of finely graded soil. After you have installed
all drainage systems, added topsoil and or soil amendments and have rough
graded the area it is time to final grade. The soil should be raked to
produce a smooth surface. This firms the soil and allows any remaining
small humps and hollows to show in the soil, which should be corrected
at this time. A mixture of soil granules and small clods of soil is preferred
over a soil with a very powdery surface. You may want to make a single
trip with a light roller over the soil in order to firm the soil and to
show any small humps and hollows which may need correcting.
Proper Time
With proper irrigation sod can be installed almost anytime
during the growing season when the ground is not frozen. It is
desirable to plan ahead, however, and consider installing sod
in the late summer to early fall. As with seeding, this time
of the year is usually very conducive to the environmental conditions
needed for rapid establishment. Although possible, it is best
to avoid installing sod during very hot, dry and humid conditions
of mid-summer. The frequent watering needed to establish new
sod during this time may encourage diseases such as Pythium blight,
which can be devastating to a lawn.
Installing The Sod
Make sure that the sod pieces are not dried out or wilted. Also be sure that
the pieces are at least 1 inch thick. If the sod is not freshly cut and
healthy do not accept it. Do not leave the sod stacked in piles. If you
can not install it immediately lay the pieces out in a shady location.
For best results the sod should be laid as soon after delivery as possible,
preferably no more than 36 hours after it is cut.
The soil should be flat and moderately moist. If needed,
water the soil ahead of time very lightly. This improves the
ability of the sod to survive and knit in faster. Lay the sod
strips on the prepared soil tightly together, edge to edge,
with staggered joints like bricks in a wall. Fill cracks with
soil if necessary. Immediately soak the newly laid sod thoroughly.
As soon as it is dry enough to walk on, lightly roll or
tamp the sod to give a good contact with the soil beneath.
This is necessary to remove any air pockets that will interfere
with proper rooting.
Watering
Correct watering after installing the sod is critical to its survival. The
idea is to keep the soil under the sod moist as well as the soil that comes
with each sod piece. This does not mean constantly wet and soggy. Usually
1 inch of water every 2 to 3 days applied in the early part of the day
will be sufficient to keep the soil moist. Measure 1 inch of water by placing
several straight sided coffee cans in the sprinkler output pattern. Check
on the moisture conditions from time to time by lifting the corners of
the sod pieces. If the sod/soil seems excessively wet by the second day
then delay watering until the third day. Water only as frequently as necessary
to keep the soil/sod moist, not soggy and wet. It is most important that
you do not over-water and avoid saturating the sod/soil since this will
prevent the sod from re-rooting and cause the roots to rot.
After the sod has knitted (rooted) to the soil (from 1-3
weeks) it is important to change the watering schedule. Watering
should be done thoroughly to soak the root zone (top 4-5 inches
of soil) but infrequently. Providing 1 inch of supplemental
irrigation every 4-7 days (depending on soil, temperatures
and rainfall) should be adequate for most lawns. There is no
need for daily watering of a sod lawn.
Mowing
Normally a newly installed sod lawn will probably require mowing 4 to 7 days
after it is installed. Avoid over-mowing; consider a length of approximately
2 inches for the lawn. Never remove more than 1/3 of the leaf blade when
mowing the lawn. It is not necessary to remove or pick up grass clippings
after mowing if you mow the lawn as frequently as is necessary. Grass clippings
do not cause thatch layers.
Fertilizing
The lawn will probably require fertilizing approximately 4-6 weeks after it
is installed. Apply a complete fertilizer with a ratio of 2-1-1 or 4-1-3
at the rate of 1 pound of nitrogen per 1000 square feet. Lightly water
in the fertilizer after it is applied. See our GreenShare Factsheet on
Developing Fertility Programs for Lawns for more information.
Adapted from Thomas Kowalsick,
Cornell Cooperative Extension, 2001
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.
|