Homeowners love their lawns, and they usually leave decisions about watering the lawn to the whims of the weather might be having second thoughts as summer gets off to a dry start.
Lawns in Missouri may need 1 to 1 1/2 inches of water a week from either rain or irrigation to stay green and growing, said Brad Fresenburg, University of Missouri Extension turf specialist.
Grasses that don’t get enough water will show symptoms of wilt and later turn completely brown. Browning means the aboveground portion of the grass is dormant while the lower portion remains alive but not growing.
Summer dormancy helps grasses survive, but there’s no guarantee that a browned-out lawn will fully recover, Fresenburg said.
Dormant lawns should receive at least 1 inch of water every two or three weeks to prevent complete turf loss. Thorough watering will bring the lawn out of dormancy, allowing growth to continue.
Water a lawn between 6 a.m. and 8 a.m., when water pressure is highest, the wind is low and water loss to evaporation is negligible. Lawns watered in the evening remain wet throughout the night, which can encourage the development of turf diseases.
Move sprinklers frequently enough to avoid creating puddles and runoff. Hand-water areas that wilt before other parts of the lawn. These hot spots may be due to hard soils that take up water slowly.
To avoid under- or overwatering, determine the delivery rate of your sprinkler system. You can do this by placing rain gauges or cans where the sprinkler is running and measuring the depth of water after 20 minutes. Multiply the depth by three to determine the sprinkler’s delivery rate in inches per hour. Most soils in Missouri will take in only about 0.25 to 0.5 inches of water per hour, Fresenburg said. If your sprinkler is delivering more than that, adjust your irrigation schedule accordingly.
Don’t water a lawn if the soil is moist, even if grass shows signs of wilt, Fresenburg cautions. Lawns with shallow root systems in saturated soil are susceptible to “wet wilt,” which can damage roots due to oxygen depletion.
“Water only when the lawns tell you to,” he said.