For some, watering a lawn is as simple as turning on a garden hose. But Brad Fresenburg has it down to a science, using empty tuna cans to get the most out of his sprinkler – and his grass.
“Tuna cans are a good tool for determining proper irrigation procedures, especially in dry conditions,” Fresenburg, an MU turf specialist, said.
Hot and dry conditions have contributed to increasing water usage during the past week. Connie Kacprowicz of the city Water and Light Department said the watering of lawns is helping drive demand, which has been near 20 million gallons a day since Friday.
Fresenburg advises homeowners to measure the amount of water applied by randomly placing tuna cans in the path of the sprinkler.
After 20 or 30 minutes, the depth of water in each can is a good indication of how much water has been applied.
Lawns need about 1 to 11/2 inches of water per week, Fresenburg said, and it’s best to space out irrigation times to achieve this goal and prevent over-watering.
Kacprowicz said many people don’t understand how much water lawns actually need and often use too much.
“Over-watering is a big problem, and people should choose the appropriate sprinkler for their lawn’s size and shape,” she said. “Homeowners should make sure their sprinkler is positioned so water hits the lawn and not the pavement.”
Early morning is the best time to water, and homeowners should avoid using sprinklers in the heat of the day.
“Watering earlier in the day will help plants absorb water more quickly and avoid evaporation due to warmer and windier conditions,” Fresenburg said.
The first step is to decide how much, if any, moisture should be applied. “When homeowners see wilting or dry, bluish-green grass blades that are tightly curled, they should start watering,” Fresenburg said.
When selecting a sprinkler, Fresenburg recommends one with adjustable settings for arc and radius to accommodate both the size and shape of the yard. He said most sprinklers have adjustable settings to alter the amount and direction of the water that’s applied.
“A good rule of thumb is to only allow enough water on the grass that can be absorbed without creating runoff or puddling,” Fresenburg said. “Any given area of grass will absorb up to a half-inch of water at a time.”
When grasses come out of winter dormancy, he said, they typically must deep-root in order to absorb moisture embedded in the soil. When early spring is a wet one, like this past year, the roots of grasses tend to remain higher in the soil.
As the soil dries out and temperatures get hotter, the roots are unable to reach deeper moisture. As a result, the grass becomes discolored and wilts.