Despite the widely-held and much-enjoyed belief to the contrary, the secret of luxuriant grass is not necessarily lots of water, certainly NOT quantities of water sprinkled with short-lived abandon whenever the mood hits the hose-happy gardener.
Indeed, the best watering practice for your particular lawn may well be not to water. To exercise noble restraint, many blades of grass, except in arid regions, require no watering.
But let’s begin at the beginning. The principles of lawn watering are elementary. First, we’ll consider the “how” (and “why”) and then the “when.”
Fundamental Rules Of Lawn Watering
One of the most fundamental rules—perhaps most often ignored—is to apply water no faster to your turf than the soil will absorb it. Light sandy soil may take as much as 3” inches an hour, which is highly unusual.
Average soils absorb little more than ½” inch (perhaps an inch) an hour, and very few sprinklers can deliver that small an amount. The result is wasteful runoff and puddling.
And if, as so often happens, people misinterpret the flooding as evidence the lawn has had enough and shut off the sprinkler, shallow watering is an additional and highly harmful result.
Above all, when you do water, water thoroughly—down to where the grassroots ought to be, 6” or 7” inches below the surface. Shallow watering is worse than no watering, for it encourages the roots to seek moisture near the surface.
The result is a disaster when sprinkling is discontinued for even a few days or when a scorching spell occurs to dry and bake the roots. Therefore, thorough deep-down watering is perhaps the most critical success factor in lawn irrigation.
Overwatering Your Lawn
But there is such a thing as overwatering your lawn—by not waiting the proper time between applications.
Too-frequent waterings keep the air spaces in the soil filled up, excluding the oxygen, and roots must have oxygen to absorb water. Therefore, a plant can lack water when standing with its feet in the water!
Also, long-continued overwatering is likely to cause lawn soils to become so dense and compact they take both water and air only with incredible difficulty. When this happens, the best remedy is to cultivate the subsoil.
Various types of implements are available for developing the soil beneath the surface without injuring the turf; spring and fall are the best times to do this, for then the soil is naturally moist, and cultivated holes are readily left in the turf, admitting water and air freely. Most professional turf growers produce their turf at various times.
How Often Should You Water?
Some excellent work sponsored by the USGA Greens Section at Pennsylvania State College indicates that lawns should be watered “only when needed.” That is, you should always wait until the grass begins to wilt slightly before watering it.
And, except creeping bent grasses, which require constant watering, the greater the interval between soakings, the better the grass stand is likely to be.
At Davis, California, an arid region where no rain falls for some six months straight in summer, daily temperatures average 100° degrees Fahrenheit. Recent tests indicate that standard bluegrass can go 24 days before it begins to wilt and needs watering.
Merion bluegrass, an improved Kentucky bluegrass, can go 36 days before starting to fade, considerably longer than the unimproved form. (However, the latter can shrink and remain dry without injury.) Bermuda grass was in the same test study—both the standard and U-3 forms. The roots of these went down 6’ feet.
The U-3 plot was watered accidentally once during the summer, and I didn’t need it then! Indeed, in all hut very arid regions, properly fertilized Bermuda grass, and even more particularly zoysia grass, provides the nearly perfect lawn without watering. (Adequately fertilized lawns, incidentally, always require less water.)
Furthermore, tests at the Beltsville Turf Gardens indicate that the combination of zoysia and Merion bluegrass is even better than zoysia alone. Indeed, the variety of zoysia and Merion bluegrass is the perfect lawn turf currently maintained without irrigation at the Beltsville Turf Gardens.
With diminishing supplies of water for domestic use and a not-too-distant likelihood, the future trend is to select the most drought-resistant grasses obtainable and provide them with the adequate fertilizing program possible. The net result should be greater lawn satisfaction with less watering than ever before.
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