There’s one thing the many kinds of warm- and cool-season grass have in common: the need for water. A proper grass watering routine is critical to the health and development of turf. But just like fertilizer and herbicides, gardeners must know when and how much water to apply. Learn all about your specific cultivar of grass, its individual needs and the conditions in which you will be growing it to achieve a lush, green lawn.
There are several factors that affect when you should water grass: soil conditions, geographic location, grass species, overall maintenance of a lawn, time of year and the amount of shade the grass receives. Of all the factors, the soil condition is one of the most critical. Grass growing on clay or loam requires less watering than the same grass growing on sandy soil.
Because lawns grow in such variable circumstances, you should follow a basic watering rule: The best time to water grass is when it’s needed. Depending on the soil type and weather conditions, most grasses need to be watered weekly. Grass growing in arid areas may need more frequent watering in the absence of rainfall. During early spring or late fall, when grass is not actively growing, look for visible cues to determine when to water. Look for discolored turf or footprint impressions on the lawn as two signs of drought stress and a need for water.
Giving grass a large enough drink of water is also key to a healthy lawn. The goal is to moisten as much of the root zone as possible. For sandy soils, that's about 1/2 inch to a 6-inch depth; for clay soils, apply about 1 to 1 1/2 inches of water. Insert a shovel or soil probe into the lawn to gauge the average rooting depth of the grass. Determine how long you need to leave your particular lawn sprinkler on to apply enough water to reach the grass roots.
When grass is watered is just as important as how much it receives. The Natural Resources Conservation Service recommends watering during early morning hours or late at night to reduce the chance of evaporation. For the best control of water, avoid irrigating when it is windy.