Michigan State University Extension
Ornamental Plants plus Version 3.0 - 00001562
11/12/99
Watering Lawns
Cool season lawn grasses go dormant during hot dry
summer weather. During the dormant period the grass is
brown and will not recover from injury or compete with
weeds. Once a dormant lawn is adequately watered, it
greens up and begins growing again.
It is necessary to water lawns that will be kept green
throughout the summer. It is not necessary to water to
keep the lawn alive. Whether or not to water is a
decision that must be made before the lawn goes dormant.
Starting a watering program, especially if the lawn is
fertilized, and then stopping, can be more harmful than
allowing the lawn to go dormant at the beginning of the
dry weather. Do not start watering if the watering can
not be kept up through the entire dry period.
Early morning watering is preferred. This provides
water during the heat of the day and little water
evaporates due to high temperatures.
Watering may be done during the heat of the day but
more of it will evaporate due to high temperatures. Wind
may affect water distribution during mid-day waterings.
Lawns require 1- to 1 1/2 inches of water per week.
This is about 640 gallons per 1000 square feet. A garden
hose would normally take about 2 hours to apply an inch of
water to 1000 square feet. Sandy soils will require two
watering per week to maintain adequate moisture levels.
Apply the water before the lawn actually goes dormant
and when it begins to wilt. Wilted lawn grasses will have
a bluish cast and footprints will persist for some time.
Once wilting occurs, begin watering.
How the water is applied is important. Sprinklers should
apply the water evenly over the entire area. To determine
how long it takes a sprinkler to apply an inch of water,
put cans at different spots in the sprinkler pattern.
Turn on the water and keep track of the time it takes the
sprinkler to put an inch of water in all the cans.
Apply the water only as fast as the soil can absorb it.
Heavy clay soils absorb water slowly. After the surface
layer is wet, the water may run off rather than soak into
the soil.
Any rainfall must be considered as part of the inch of
water for the week. Summer rain often comes in the form
of thunderstorms during which a lot of water falls in a
very short time. Since much of this water runs off, it is
not captured by the soil for plants to use. Do not
consider short, intense rainstorms as providing a
significant amount of water for lawn growth.
Homeowners with underground sprinkler systems should
set the system to apply water for 20 minutes each day at
noon.
Lawns infected with certain diseases have circles of dead
grass with green grass in the middle. These symptoms can
be reduced by watering lightly every day to reduce
moisture stress.
This information is for educational purposes only. References
to commercial products or trade names does not imply
endorsement by MSU Extension or bias against those not
mentioned. This information becomes public property upon
publication and may be printed verbatim with credit to MSU
Extension. Reprinting cannot be used to endorse or advertise
a commercial product or company.
This file was generated from data base ZZ on 01/19/00.
Data base ZZ was last revised on 11/12/99.
For more information about this data base or its contents please contact
heatley@msue.msu.edu . Please read our
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