If having a lush, green lawn fits in your vision of a green lifestyle, but you don't want to needlessly bankrupt your local water supply (and run up your water bill), there are some strategies you can use to keep your grass green and reduce your water use. While the greenest option is to ditch the manicured lawn and go with a native garden or xeriscaped landscape, if you like your lawn to be a pleasant place to play and relax, here's how to cut back on its water use.
Learn what your community's restrictions are.
Many areas of the country have responded to increasing water shortages by carefully limiting how many times per week you can water your lawn, at what times you should water, and for how long. Be sure to heed these restrictions.
Water well to encourage deep root growth.
Frequent shallow waterings encourage weed germination, and they also cause the grass plants' roots to grow shallow, leaving the plant more susceptible to drought and to certain diseases. Watering only when your grass really needs it encourages the roots to grow deeper, but only if you apply enough water each time to penetrate the root zone. The most accurate way to determine the depth of the root zone is to dig a small hole and measure how far the roots go down. Alternatively, you can follow these general approximations: if you have a bluegrass lawn, each watering should moisten the soil to 6-8 inches, while for most other grasses, the water should penetrate 8-12 inches.
Water early in the morning. When you use sprinklers, some water evaporates before it hits the ground; the hotter and windier it is, the more water you lose to evaporation. To reduce the amount that never reaches the grass, water sometime between 4 a.m. and 9 a.m., when the air is still cool and the wind is generally more calm.
Don't water the street or sidewalk. We've all seen it: the sprinklers set up to water half a lawn and half the street, too. Any water that hits impervious surfaces like your driveway or the sidewalk is totally wasted, so take care to make sure your sprinkler doesn't overshoot its bounds.
Avoid runoff. Along the same lines, if you allow water to run off your lawn and in to the driveway or street, it isn't doing your grass any good. If water starts to run off your lawn before you've been able to give it a good, deep watering, turn off the water for 15 or 20 minutes to let the soil absorb the water, and then continue watering as needed; rotating a sprinkler from one area to another will also do the trick.
Water different areas with different amounts. If part of your lawn is shrouded by shade trees, it'll require less water than a south-facing slope that gets lots of solar exposure, so pay attention to how the sun and other features like trees affect your lawn, and adjust your watering patterns accordingly.
Consider letting your lawn go dormant this summer. If you live in a climate with moist, mild winters and dry summers, like where I live in the Pacific Northwest, you'll have a beautiful green lawn for most of the year without having to water your lawn at all. It'll dry out and get a little brown around the edges in the heat of summer, but it won't take long for it to get green again once the weather shifts. And, if your water bill skyrockets every summer, our best advice is...
Think about getting rid of the lawn altogether. Though a symbol of your green thumb and proud homeownership, lawns are high-maintenance and use a tremendous amount of water -- almost 8 billion gallons a year in this country. The greenest option is to not have a big green lawn at all.
Difficulty level: Easy to moderate