When Watering Is Needed
The only way to keep grass green during dry periods is to water it. Most
lawns use 1 inch of water per week. Heavy claylike soils hold 2 to 3 inches
in the root zone, enough to last a lawn for 2 weeks following a good
soaking. Sandy soils hold only 1/2 inch or less so they need watering more
frequently. On the heavier clay and silt soils, watering should be fairly
slow and prolonged. It may take more than an hour of sprinkling to soak 2
inches of water deeply without any running off. On sandy soils such as occur
near the beaches, water would be wasted if more than about 1/2 inch were
applied, and this soaks in about as fast as you can water. Because it drains
so quickly, it should be watered every 3 or 4 days during drought periods.
Well-established lawns can usually become completely brown from drought
yet come back green when conditions again turn favorable. So most watering
is for appearance's sake rather than for the health of the grass. As a
matter of fact, watering sometimes helps the weeds more than the grass,
encouraging annual bluegrass, nutgrass and other water-loving weed species.
If you are interested in installing an irrigation system, select one that
applies water evenly at the right rate. I n most cases it is advisable to
have them installed by a professional to be sure of proper coverage, correct
pipe size and adequate water pressure.