By Brad Haire
University of Georgia
Since March 1, some places in north Georgia have had good rainfall. But some are 2 inches to 3 inches below normal. South Georgia has been dry, with only a half-inch to an inch of rain across most of the region, about 5 inches below normal.
Just two weeks without water can be enough to hurt most grasses, said Kerry Harrison, an irrigation specialist with the University of Georgia Cooperative Extension.
But you don't want to just turn on the sprinklers anytime you feel the lawn needs a drink. This could waste water and damage lawns.
"It could get you in trouble, too," Harrison said.
Georgia has statewide watering restrictions now. There are some guidelines.
If your street address is an odd number, you're asked to water only on Sunday, Tuesday and Thursday. If it's an even number, you're asked to do it on Monday, Wednesday and Saturday. "There's no outside watering on Friday," he said.
New automated irrigation systems, Harrison said, must be equipped with rainfall sensors to stop them when it rains. Watering guidelines are enforced by local authorities.
But homeowners can easily supply their lawns with needed water and still follow the guidelines, he said.
It doesn't matter if you use a permanent system or a sprinkler attached to a hose. The first thing you need to know is how much water you're applying and how fast.
"Not knowing your water application rate is like driving a car with no speedometer," he said.
Different systems apply water at different rates. Hose-sprinkler systems vary the most. Space three rain gauges within the watering area of your system. Look at your watch. After an hour has passed, check your gauges to see how much water your system puts out in that time.
Most lawns grow best when they get 1 inch of water a week, either from rain, irrigation or combination of the two. And they prefer long soakings. In dry weather, water only once or twice a week to get that 1 inch.
Light, frequent watering can cause turf grasses to develop shallow roots. This can lead to many problems, including disease and insect damage and discoloring from poor fertility.
The grass at the very end of a sprinkler's trajectory may not get as much water as the grass closer to the sprinkler. Permanent systems should be set for overlap in sprinkler patterns to adjust for this. Remember this when you move your hose-sprinkler system. You want your lawn to be uniformly wet.
Water at the right times, too: early morning or late at night, Harrison said. If you don't, you could just waste time and water.
"We have research and evidence to show that you can lose as much as half the water if it's applied during peak daylight hours," he said.
High temperatures and high winds can evaporate water or blow it off-target, too, he said.
Watering during the day also increases the time grass is wet. This can lead to diseases. Watering at night won't hurt grass that's already wet from dew. The turf gets the water it wants and is drier during the day.
(Brad Haire is the former news editor with the University of Georgia College of Agricultural and Environmental Sciences.)