True, water is essential to lawns. But too much or too little can harm them. Running the sprinkler all night wastes a precious resource and sets up the right conditions for disease. Frequent, light watering sets your lawn up for trouble in hot weather. Here are a few easy pointers for correct watering.
You want deep, infrequent waterings that get into the root zone. That means at least half an inch twice a week, or an inch once a week as a rule of thumb.
Early in the morning is the ideal time to water for most lawns. There's less wind, less hot sun, and your lawn has a full day to dry. Watering at night invites mildew and fungus. In the hot afternoon, much of your water can be lost to wind and evaporation. If you live in the dry southwest, though, the rules are different. There, watering in the evening or night causes less evaporation.
You can water carefully and properly, but if the water isn't absorbed, your efforts are wasted. The only way to tell for sure whether the water is soaking in is by testing. Stick an 8-inch screwdriver into the ground after watering. If it goes in 6 inches, you've watered well.
Sprinklers are ornery things. They don't always put water down equally. To make sure water is going where it's supposed to, place a few empty soup cans around your lawn, and run your sprinkler for about 20 minutes. If water collects evenly in the cans, you know your sprinkler is doing its job.
How do you know how much you've watered unless you've measured? That's what's nice about water gauges. At a glance, you can tell how much water has gone on your lawn - either from your sprinkler or rain. You'll find gauges at most lawn and garden centers.