Watering deeply at longer intervals (preferably only twice a week) is better for your lawn than watering lightly and frequently. Your lawn develops roots to the depth where the water saturates to in the soil. If you water lightly, all the water stays near the soil surface, so your lawn can only develop shallow roots. Watering frequently is not healthy for any lawn. When you water deeply, you encourage your lawn to develop a deep, more healthy, root system.
When you water matters. The experts don’t recommend that you water your lawn between 10 a.m. and 6 p.m. This is the hottest part of the day when over half of the water used to irrigate may be lost to evaporation. Also avoid watering in the dead of night. Not much water will evaporate, true, but the sitting water on your lawn can promote the growth of various fungi that can damage your lawn. Experts teach you should water between 4 and 6 in the morning.
Keep the whole plant healthy—including the roots. The goal should be for the roots of your lawn to remain somewhat damp between waterings but not too wet. When the soil under a lawn is drenched constantly, root rot can develop, and it’s difficult for oxygen to be drawn into the soil.
Add compost. Adding no more than 3 inches of compost material to your lawn in the spring or fall can help your lawn stay healthy in a couple of ways. It will form a surface cover to hold water in the soil, and it will provide nutrients to your lawn as well.
The key is to water only when your lawn needs it. It’s easy to grasp the problem of underwatering—your grass turns brown and dies. But overwatering can also compromise the health of your lawn—not to mention it wastes water. So strive to strike a balance between the two extremes. Give your lawn just the water it needs to thrive and no more. Watering twice a week will help you achieve this.