Water is essential for supporting plant life. It is the carrier in which
dissolved minerals enter and move about in plants. Water is also necessary
for photosynthesis, the chemical conversion of sunlight into carbohydrates,
to occur. Plant and environmental cooling also occurs as a result of water
release through leaves as vapor. Finally, water has a structural role
in maintaining plant turgidity or rigidity; herbaceous plants undergoing
water deficit often become limp. Although there are differences among
various grasses and plants in their water demands, most lawns and landscape
plants normally grown in the north central region will benefit from irrigation
that supplements natural precipitation, especially during prolonged heat
and drought.
General Lawn Watering Information
In the north central region, there are two ways to manage your lawn
regarding summer irrigation. One is to water your lawn on an as-needed
basis. In this method, your lawn is watered throughout the growing season
when natural precipitation is inadequate to support active growth and
maintain green color.
Pest problems or poor culture aside, the presence of an adequate quantity
of water during summer is the environmental factor that determines whether
a lawn is green and growing or brown and dormant. Thus, supplemental irrigation
is essential during many summers to maintain green, actively growing lawns.
Cool season lawn grasses—bluegrasses, ryegrasses, fescues, and
bentgrasses—require approximately 1 to 1 1/2 inches of water per
week during the growing season to maintain green and active growth. Even
when they are watered, however, the growth of cool season lawn grasses
slows during summer’s hot, dry weather because environmental conditions
are not within the optimum range for turfgrass growth.
An alternative method of managing lawn irrigation is to allow the lawn
to go dormant during hot, dry weather. Unwatered lawns of cool season
species normally become dormant and brown during hot, dry periods and
then recover acceptably when growing conditions improve in the late summer
or early autumn. During most years, lawns in the north central region
can safely survive periods without summer irrigation.
Lawn Watering Benefits and Considerations
There are several benefits derived from lawn irrigation, as well as
some considerations about this practice. When lawns and landscape are
properly watered, appearance is maintained and pride of ownership enhanced.
In addition, proper irrigation often decreases weed invasion and allows
lawn grasses to better tolerate insect and disease pressure. On the other
hand, improper irrigation practices—either too much or too little
water—can lead to poor lawn grass health and increased weed, insect,
and disease problems. Excessive watering can cause rapid turf growth resulting
in more mowing and clippings. It can also lead to a shallow turf root
system and weed and pest invasions. Underwatered turf becomes open and
sparse, developing a poor appearance and allowing weed invasion. Additionally,
for some individuals, the financial and environmental costs of season-long
irrigation can be substantial in areas where high-quality water is in
short supply. The choice to irrigate home lawns should be made after weighing
the specific facts in your locale.
Recommendations for
Effective Lawn Watering
The following practices are recommended to achieve effective lawn watering.
Do not begin watering at the first sign of warm weather. Root-system
elongation is the initial turfgrass response to droughty conditions.
Do not delay watering, however, until the lawn has gone dormant. After
an initial droughty period, begin watering to maintain green color and
active growth.
To determine when to water, walk on your lawn to see if your footprints
are visible behind you. On lawns in need of water, the grasses will
not spring back following trafficking. Where moisture is adequate, grasses
will spring back. Another method to determine the need for watering
is to watch for grass color changes. Very often, as soils dry, lawns
with inadequate moisture develop a dark blue or purple cast. Finally,
you can use a soil sampling tool to examine soil for the presence of
moisture.
Select a sprinkler based on yard size and shape. Many sprinklers have
water distribution patterns that can be adjusted to fit a variety of
sizes and shapes. It is not necessary to have an in-ground sprinkler
system to have an attractive yard, although an in-ground system can
reduce the labor of moving a sprinkler and hose from spot to spot.
Supply a uniform amount of water to the entire lawn. Do not supply
excessive water in some spots and inadequate amounts in others. When
sprinkling, monitor water distribution by placing coffee cans or some
other straight-sided vessels at various points beneath the sprinkler’s
pattern. Measure the quantity of water captured in each container and
overlap sprinkler patterns to supply the entire lawn with a uniform
quantity of water.
It is best to water deeply and infrequently. Water to the depth of
the turf root system, that is, supply enough water in one irrigation
to moisten the entire soil profile where roots are growing. Usually,
1 inch of water is adequate to supply this amount. Do not water again
until this soil area has dried, and then water the entire soil-root
zone again. This entails monitoring soil conditions with a trowel or
soil sampling probe. Coarse, sandy soils require more frequent watering
than fine-textured clay soils. During hot, dry, windy, and sunny conditions
lawns will also require more frequent irrigation, as will exposed, open
areas, or turf that is excessively fertilized with nitrogen.
Avoid light, frequent irrigation unless you have just seeded an area.
Light frequent irrigation encourages shallow turfgrasses rooting and
annual weed invasion.
Watch newly planted lawns, both seeded and sodded, closely. Young
grass plants and newly installed sod have smaller root systems than
their fully established counterparts. These plants will usually require
frequent irrigation until their root systems have developed and they
have become established.
Do not apply water faster than the soil can absorb it. Do not create
puddles by overwatering. On slopes, apply water slowly enough to be
absorbed into the soil and not run off the surface.
Water early in the day. This can reduce water loss due to evaporation
and also reduce the incidence of several lawn diseases.
Do not follow an irrigation regime that causes your lawn to bounce
between active growth and dormancy. Each time your lawn resumes growth
after dormancy, stored plant reserves are depleted. A continuous pattern
of dormancy followed by active growth can stress turf and may slow its
recovery when improved weather conditions return.
Additional Lawn Management Practices
Related to Water Conservation
The following practices are recommended to reduce the water requirements
of a lawn.
Do not mow turf too short. During spring and autumn in the north central
region, maintain most lawns at 2 to 2 1/2 inches. Raise this height
by 1/2 inch during the summer and any time the lawn is stressed by pests
or environmental conditions. Mow frequently and never remove more than
one-third of the grass blade at any one mowing.
Do not supply excessive nitrogen fertilizers during hot, dry spells.
Nitrogen can encourage the lawn grasses to grow excessively during periods
when environmental conditions are not conducive to lush growth. These
conditions can lead to disease problems, excessive water use, and excessive
mowing. Be sure to fertilize in late summer or early autumn. This fertilization
allows cool-season grasses to recover from summer stresses and go into
winter in good shape.
Limit lawn traffic during hot, dry periods.
Maintain a soil pH of six to seven.
Core aerify cool season lawns in spring or autumn to relieve soil
compaction and improve soil aeration and water movement. Proper core
aerifying usually improves root growth and overall lawn health.
Maintain thatch levels at 1/2 inch or less. Excessive thatch reduces
your lawn’s ability to tolerate droughty conditions.
Do not use pesticides—herbicides, insecticides, and fungicides—as
a substitute for proper lawn care. Apply these products only when proper
management practices fail to produce a satisfactory lawn. Always read,
understand, and follow the manufacturer’s label directions when
using any pest-control product.
Management Practices for Unwatered
Lawns
The following practices are recommended in order to achieve the best
possible appearance for unwatered lawns.
Grow drought-tolerant grasses. Common types of Kentucky bluegrass,
the tall fescues, the fine-leaf fescues, zoysiagrass, and buffalograss
are the most naturally drought-tolerant grasses for the north central
region.
During periods of extreme heat and prolonged drought, apply 1/4 to
1/2 inch water every 2 to 4 weeks to unwatered lawns. This will maintain
moisture in stems and roots so the grasses can survive to regrow when
conditions improve.
Follow recommendations outlined in the section above, "Additional
Lawn Management Practices Related to Water Conservation."
Lawns represent a sizable investment in both time and monetary expenditures.
A properly managed lawn is a source of pride and, as part of a quality
landscape, can increase your home’s value and improve its physical
environment. Whether it is watered or allowed to go dormant, lawns should
be treated as an important portion of the landscape that deserves consideration.
