SEAISLE 1 SEASHORE PASPALUM
Suggested Management Practices
For Home Lawns
(Revised October 28, 2002)
Home Lawn Management for SeaIsle 1
Seashore paspalum has many attributes that make it an
environmentally "friendly" turfgrass. It is
important, however, to recognize that seashore paspalum
has unique management requirements and that homeowners
should not rely on management regimes for other
warm-season grasses to maintain a healthy and beautiful
'SeaIsle 1' seashore paspalum lawn. Here are some general
recommendations for maintenance of a SeaIsle 1 lawn in
the southern United States. Because growing conditions
vary throughout the south, it is a good idea to check
with your local Cooperative Extension office for pest
identification and for irrigation and fertility
recommendations specific to your area's soil types and
growing season. Also check to verify the legal use of
fungicides, insecticides, and herbicides on home
lawns/landscapes in your area.
FERTILITY
General Fertility Recommendations: Fertility
recommendations vary depending on your location in the
southern United States. For more precise fertility
recommendations for your area, consult with your local
Cooperative Extension Service.
Nitrogen (N):
Apply up to 0.5 lbs. N / 1000 sq. ft. / application every
two months during the growing season. A good source is
organic fertilizer products. In many parts of the south,
seashore paspalum will go into winter dormancy. It does
not require fertilizer during that period. Only fertilize
your lawn when it is actively growing. The highest rates
will be in the spring after greenup and early in the fall
season well before the first predicted frost.. Begin
fertilizing about 1-2 weeks after spring regrowth begins.
Do not apply more fertilizer than recommended here at one
time, since you can get a growth surge in response to the
fertilizer. This can lead to increased thatch production
and predisposition to increased insect and/or disease
activity.
If N deficiency is evidenced by yellowing of lower
leaves, slow growth, or loss of stand density, more
frequent (every 6 weeks) fertilizer applications can be
made. Apply a total of 1.5 to 3 lbs. total N per 1,000
sq. ft. on an annual basis.
Phosphorous (P):
Phosphorus is required for root development and plant
growth. Good phosphorus nutrition is especially important
during sprig or sod establishment. In some parts of the
south, rates should be in relation to annual N
application and are usually in the range of 1 lb
phosphorus as P2O5 per year per 1000 sq. ft. However,
where soil P levels can be high, it may not be necessary
to add P to the lawn. Soil testing for amount of P in the
soil is recommended. If your soil tests high for P, look
for a fertilizer source with up to, but no more than, 2%
P in the bag. Excessive phosphorus is a potential
pollutant, so its use should be limited to those areas
where it is truly lacking in the soil. In other parts of
the south, contact your local Cooperative Extension
Office for information regarding phosphorus application.
Some areas may require applications 2-3 times annually to
make sure this nutrient is available to the turfgrass
roots.
Potassium (K): Potassium is required by the turfgrass
plant for root formation, root growth and persistence,
wear tolerance, drought resistance, and disease
resistance. Good potassium nutrition aids the plant in
tolerating temperature extremes, as well as stress caused
by traffic. Potassium deficiency is implicated in some
turfgrass disease complexes, and it is generally
recognized that adequate potassium fertility is important
for good turfgrass health. Seashore paspalum will quickly
use up potassium in the soil, thereby increasing the need
for additional applied potassium. Look for a fertilizer
with a high 3rd number on the bag, such as a 15-2-15 or
15-2-22. In high rainfall areas or after high rainfall
events, addition of potassium would be recommended since
this nutrient is quite mobile and will move readily with
various water sources.
Minor elements: Seashore paspalum will respond to
minor element fertilizer applications if these elements
are deficient in the soil. In areas with either high
(>8.0) or low (<5.5) pH, micronutrients are sometimes not available for plant uptake. Micronutrients can be added by using a complete fertilizer. Application of iron will provide a quick green-up without promoting a growth surge. It is often beneficial to apply iron in the summer months rather than nitrogen so as not to promote shoot growth during rainy seasons. Magnesium is essential for good color retention, and manganese plus zinc are key nutrients for activating the salinity tolerance mechanism.
Fertilizer Specifics:
1. Newly established lawns from sod:
An initial fertilizer could include organic sources
applied preplant with the sod laid on top of this
application. Fertilize when shoot growth begins
(generally 7-10 days) with ½ - 1 pound of nitrogen per
1000 square feet in a complete fertilizer. An ideal
fertilizer ratio would be a 1:2:3 N:P:K, with 2.5 - 5
pounds applied per 1000 sq. ft.for this initial
application. This will provide extra phosphorous and
potassium in relation to nitrogen. Try to keep nitrogen
low in relation to phosphorous and potassium for this
first fertilizer application. Subsequent fertilizer
applications for established lawns should be based on
response of the grass. If you apply high N rates, the
grass will rapidly respond and you will be mowing more
frequently. In addition, high N rates will dispose this
grass to disease problems if irrigation or rainfall is
excessive.
2. Newly established lawns from plugs:
Fertilize when you see new shoot growth (stolons or
runners), about 7-10 days after planting, with ¼ - ½
lb. of N per 1,000 square feet. The nutrient ratio should
be 1:2:3 or 1:2:4 N:P:K for this initial application.
Fertilize again with this same amount of fertilizer 2-3
weeks after the initial application.
3. Established lawns:
After your paspalum lawn is established, apply
fertilizer every other month during the growing season.
If you are applying a water soluble nitrogen source, do
not apply more than ½ lb. of nitrogen per 1,000 square
feet at any one application. If you are using a slow
release nitrogen source, you may apply up to 1 lb. of
nitrogen at any one time. Apply a total of 2-3 lbs. of
total nitrogen throughout the growing season. Remember to
base your lawn's phosphorus needs on soil test results.
Look for a fertilizer that has equal or slightly higher
amounts of potassium (K) than nitrogen when fertilizing a
paspalum lawn. Organic fertilizers are a good choice to
use when fertilizing this grass.
Remember that seashore paspalum does not grow well
under high fertility regimes. In fact, too much
fertilizer can cause excessive growth, which may result
in problems with thatch accumulation, insects, and
disease. The grass is also more prone to scalping since
its growth rate will be high.
MOWING
Mowing has a significant effect on lawn
appearance. The height of cut, frequency of mowing, and
type of mower all have a major influence on your lawn's
health and attractiveness. Fertility, soil moisture, and
temperature determine the optimum mowing schedule.
SeaIsle 1 should be maintained in a home lawn at a mowing
height of 1.0-2.0 inches. If using a rotary mower, mow at
the higher height. Remember that it is imperative to keep
the blade sharp, particularly with a rotary mower. Reel
mowers will give a better cut, particularly when mowing
at the lower height, but are not necessary for
maintenance of a SeaIsle 1 lawn.
Mowing should begin as soon as the roots have pegged
down into the soil, generally 7-14 days after planting.
It is critical to bring the mowing height down very
slowly and to not remove too much shoot tissue at any one
mowing. Seashore paspalum does not recover very well from
scalping, or removal of too much shoot tissue at any one
time. Therefore, initial mowings should be at heights
similar to the height maintained at the sod farm.
You can gradually reduce the mowing height over
several mowing events or after the grass emerges from
winter dormancy. During the summer, when the grass is
growing vigorously, it will take longer to reduce the
mowing height, unless you plan to mow more than once a
week. Only remove 1/3 of the leaf canopy at any one
mowing. Clippings can be left on the ground and will not
contribute to thatch build-up.
Generally the higher the mowing height, the more open
the canopy and the lower the mowing height, the tighter
the canopy, resulting in minimal weed competition.
Because of a tighter canopy, the lower mowing heights
seem to overwinter better with prolonged cold
temperatures than the higher mowing heights.
IRRIGATION
During Establishment:
Grass that has just been planted as sod has only a
portion of its root system and is vulnerable to drought
stress. To keep roots from drying out, irrigate two to
three times a day for short periods for the first 4-7
days after planting. Then, irrigate once daily and apply
½" for another week or so. Gradually extend the
number of days between irrigation events and apply ½-1
inch of water with each event. Four to five weeks after
sodding, the grass should be irrigated once weekly in
order to force the root system deeper into the soil. Root
establishment can be determined by lifting a corner of
sod and observing the root development. Learn to read the
grass and its response to irrigation. Do not overwater
this grass since this activity creates an ideal
environment for pathogens and predisposes the grass to
disease attack. The strategy is to gradually decrease the
irrigation frequency until you can meet state-mandated
water restrictions. Train the roots deep into the soil
and this grass will exhibit excellent drought resistance.
Under cloudy or cool conditions, you do not need to
irrigate as frequently or with as much volume when
compared to hot, dry, or humid conditions.
Established Turf:
Your goal now is to only irrigate the lawn when the grass
is showing signs of drought stress. These signs include
leaf blades folding in half, a blue-gray color, and
footprints that remain visible long after being made.
Make these visual assessments during the morning hours.
The frequency and amount of irrigation to apply will
depend on where you live, time of year, and general
climatic conditions. Once you have identified the onset
of drought stress, irrigate established seashore paspalum
on a need-only basis. Check with your local Cooperative
Extension Service for irrigation recommendations for your
area. The amount of evapotranspiration will usually
dictate how often and how much irrigation water will be
needed.
It is important not to overwater your lawn!
Overwatering leads to a number of problems and is a
leading factor in lawn decline. Less frequent, longer
irrigation events on established turf provide the
greatest benefit and increase the overall health of your
lawn. Irrigate in the early morning hours so that leaf
blades have a chance to dry out during the day. This
reduces disease incidence and is better for the overall
health of your lawn.
Use of alternative water sources:
Although seashore paspalum is tolerant of a wide range of
irrigation water quality and salinity, and some effluent
water can be used almost as if it were fresh water, soil
or plant nutrient relationships can be affected by the
use of alternate water sources. Therefore it is important
that the homeowner seek advice on irrigation and salt
mediation requirements specific to his area before
deciding to use effluent or high saline irrigation water.
It will not be unusual for the management requirements to
vary within a subdivision community. In general, sandy
soils will be easier to manage than heavy clay or silty
soils, and higher rates of irrigation will be required
when saline water is used for irrigation. Contact your
County Extension office for specific recommendations
geared to your conditions. When irrigating with saline
water you must take care to minimize the buildup of
excess salts in the soil.
Irrigation during winter:
Irrigation may not be needed during the winter if
your seashore paspalum is brown and dormant due to
freezing temperatures. However, in some parts of the
south, grass often goes semi-dormant, as evidenced by
green leaves but little growth, because of cold
temperatures and shorter daylengths. In this situation,
it is recommended that when no rain has been received for
a 2 to 3 week period, irrigation can be applied every 14
to 21 days to maintain root metabolic activity, to
prevent cold temperature desiccation, and to enhance
spring greenup.
WEED CONTROL
General:
A healthy turf that is fertilized, irrigated, and mowed
properly will out-compete many weeds. However, any lawn
may develop some weed pressure even with the best care.
There are three basic types of weeds: broadleaf, grassy,
or sedges. Each weed type requires a different product.
Remember, the label is the law, so be sure to read and
follow label instructions! Check with your county agent.
Broadleaf Weed Control:
There are a number of products that can effectively
remove broadleaf weeds from seashore paspalum. These
include Trimec Southern (make sure to use the Southern
formulation!), Lontrel, or any of the Weed Be Gone
products that are available in lawn and garden supply
stores.
Grassy Weed Control:
There are fewer options for removing grassy weeds from
seashore paspalum without also injuring the lawn.
Professional pest control operators can choose from a
wider range of chemicals, but even they have limited
options for control of grassy weeds. Your best bet here
is to apply a "preemergence" herbicide based on
potential weeds you had last year. You need to know where
the weedy areas are before you apply an herbicide, so
take note of those areas when you see them and you will
be ready to deal with them the following spring. Check
with your local Cooperative Extension office to identify
the weeds and to determine when their germination times
occur in your area. Timing of preemerge herbicide
applications can often be keyed to soil temperatures or
night temperatures. Products that can be safely used for
this type of weed control on seashore paspalum include
Halts and Ronstar.
Sedge Control:
Products that can safely be used for sedge control
include Manage or Image.
Using salt to control weeds:
Since seashore paspalum is tolerant of salts, spot
applications of rock salt can be helpful. Cover the weed
with a white coating of salt, but do not turn on the
irrigation system. Let the morning dew gradually dissolve
the salt and slowly desiccate the weed. The idea is to
kill the weed without injuring or burning the lawn. The
salt will at the same time furnish micronutrients to the
turf.
INSECT/DISEASE CONTROL
Seashore paspalum has problems with a few insect pests in
some environments. These insects can include sod
webworms, fall armyworms, billbugs, and mole crickets. If
you notice insect damage, there are a number of products
available that can safely treat the insects without
harming the lawn. Contact your local Cooperative
Extension Service office for more information on insect
identification and control. Timing of application is
usually the key to effective control.
Disease problems are also seen in paspalum, depending
on the environment, the amount of fertilizer applied, and
the presence of environmental stresses. Scalping the
lawn, or removing too much leaf tissue at any one time,
is a primary source of stress that may induce disease.
Problems may also arise from over or underwatering during
establishment, which can weaken the grass and make it
more vulnerable. It is important first to determine the
disease or organism, then to apply a fungicide, if
appropriate, to arrest the disease and, finally, to take
proper steps to deal with the environmental condition
that may have contributed to it in the first place.
Contact your local Cooperative Extension Service office
for more information on disease diagnosis and control
measures.
SOURCES AND LINKS
These management suggestions have been compiled from the
following sources:
Seashore Paspalum website: www.griffin.peachnet.edu/cssci/turf/paspalum/paspalum.htm.
SeaIsle 1 website: www.seaisle 1.com
GA Cooperative Extension Turfgrass website: www.georgiaturf.com
. Click on 'seashore paspalum'.
Seashore Paspalum, the Environmental Turfgrass, by
R.R. Duncan and R.R. Carrow, Clock Tower Press, 2000. (www.clocktowerpress.com)
For their kind assistance in deveolping this article we
extend thanks to Dr. R. R. Duncan, SeaIsle1
developer, Laurie E. Trenholm, Ph.D., Assistant
Professor/ Extension Turfgrass Specialist, Urban
Turfgrass Program University of Florida, and Earl
Elsner, Ph.D., retired Director of the Georgia Seed
Development Commission
Specific questions can be sent to "Ask the
Expert" on this website or directly to Paul Raymer (praymer@gaes.griffin.peachnet.edu).
|