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of Rhode Island GreenShare Factsheets
Watering of Turf
the amount of rainfall received in the Northeast is generally
ample, it is not always uniformly distributed throughout the
year. It occasionally becomes necessary to provide supplemental
irrigation to keep turfgrasses growing well, especially during
summer months. Water is lost from the soil through gravitational
drainage, evaporation, and plant use. If plant or soil water
content becomes limited, drought stress, followed by turfgrass
death, may occur.
variables influence the amount of water used by turfgrasses.
These include amount of solar radiation, humidity, grass species
and rate of growth. Rooting depth and soil texture also affect
the water requirements of turfgrass. Grasses which are more deeply
rooted can extract water from a greater volume of soil and may
be more drought tolerant than shallow-rooted species. Finer textured
soils hold more water than coarse soils and require less frequent
irrigation. Because so many factors interact to determine turfgrass
water use, it is difficult to give a general estimate of how
often to water a lawn. The best technique for determining when
to irrigate is to observe both soil and plant conditions in the
lawn and then water when the turf needs water, rather than based
on the calendar.
following turfgrass types are listed in order of their tolerance
fine-leaved fescues include hard fescue, creeping red fescue
and Chewings fescue. Sheep fescue is a fine fescue which has
excellent drought tolerance, but which is more suitable for areas
mown only once or twice per year.
conserve water and avoid the detrimental effects of overwatering,
water lawns just prior to the development of wilting and drought
stress. Wilting occurs because the plant's internal water content
drops so low that the plant cannot remain turgid (stiff), and
plant cells begin to shrivel. Turfgrasses undergo a series of
visible changes when they begin to wilt. Development of a bluish-green
coloration and the rolling or folding of leaf blades are two
noticeable changes associated with wilting. If footprints remain
visible on lawn for several minutes after walking on it, the
turf is not very turgid and wilting is occurring. Although these
initial symptoms of wilting will not usually presage permanent
injury to the lawn, the lawn should be watered soon to avoid
drought stress and possible turfgrass death. Examining the soil
is also helpful in determining when to irrigate. Use a soil probe
or garden spade to observe the soil to a depth of approximately
six inches. If the soil appears dry, it is time to water.
lawn watering often encourages shallow rooting and may predispose
the lawn to increased disease and greater susceptibility to stress
injury. Watering deeply and less frequently provides for improved
turf growth and increased water conservation compared to light,
irrigation becomes necessary, wet the soil to a minimum depth
of 4 to 6 inches. This amount of water varies with soil texture,
but approximately 1 inch of water should thoroughly wet most
soils to a depth of 4 to 6 inches. Placing several empty cans
(tuna or cat food cans work well) under the sprinkler allows
you to determine when an appropriate amount of water has been
can be applied at any time during the day or night. Both day
and night watering have advantages and disadvantages. Midday
watering cools the turf and reduces heat stress on hot summer
days. If drainage is poor, pools of standing water can become
very hot and result in turf death due to scalding. Midday watering
is also relatively inefficient due to substantial evaporation
watering may incite or aggravate disease problems. However, the
turf is usually wet during the night anyway, even if irrigation
is withheld, because of dew formation. Recent research has suggested
that the duration of leaf wetness (the number of hours that the
leaf blade is actually wet) has a greater impact on disease incidence
than night watering per se. In that case, watering during early
evening or late morning (just prior to or following dew formation)
could result in increased disease by prolonging leaf wetness.
Night irrigation helps to conserve water because of minimal evaporation
at night. Night watering should be avoided, however, when disease
is present and actively damaging the lawn, or during periods
of very hot, humid weather. Very early morning watering, before
dew has dried, is the best solution, because it provides for
efficient use of water (low evaporation) and does not contribute
to disease pressure.
periods of prolonged drought, some turfgrasses have the capacity
to avoid death by entering into a state of dormancy. Kentucky
bluegrass is the most common turfgrass exhibiting this drought
avoidance mechanism. Dormant turf appears straw-colored and does
not grow. When drought conditions cease, usually due to late
summer or fall rains, the turf is capable of resuming normal
growth. Although the lawn may recover when water is no longer
limited, the grass is much more susceptible to disease, insect,
traffic and wear injury when it is dormant, because it is not
growing. Disease and insect injury may also go undetected because
the turf is already brown. This can result in the loss of large
areas of turf, a loss which may have been prevented if the lawn
had not been dormant. Weed infestations can increase because
the grass is not actively growing and cannot compete with more
actively growing weeds. If a quality green lawn is your goal,
drought-induced dormancy can be prevented by timely watering.
from the University of Massachusetts Extension, 2000
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.
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.
of Rhode Island Cooperative Extension provides equal program