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Homeowner’s guide to watering summer lawns

URBANA, Ill. – “To water or not to water the lawn” is a perennial discussion for homeowners says Richard Hentschel, University of Illinois Extension horticulture educator. “What you decide at the beginning of the lawn growing season influences your management decisions for the rest of the season,” Hentschel says.

Full-season watering

Watering throughout the season means homeowners will be mowing more as the grass will continue to grow. There is more of a time commitment for mowing and more maintenance to keep mower blades sharp. Homeowners will have a fertilizer schedule that also continues through the summer months to take advantage of the water.  

“When you do water, best management practice is to water deeply, yet infrequently,” Hentschel says. This style of watering will drive roots deeper into the soil profile, making more water available for growth as the upper profile dries.

Besides “neighborhood bragging rights,” the upside of a higher level of lawn management will be grass clippings for mulching vegetable gardens or perennial beds or a compost bin or pile. Best mowing practices suggest a mowing that is so timely that clippings are just returned to the lawn to decompose naturally, releasing nutrition back into the soil.

To keep the lawn healthy and competitive against weed competition, Hentschel suggests following the one-third rule. “Mow often enough to only remove a third of the grass blade at a time,” he says.

Irrigation systems

"If you are lucky enough to be running an irrigation system, be sure it has the correct spray pattern overlap" Hentschel says. "If it is a zoned system, be sure to adjust for exposures." Western and southern exposures will need more water than a northern or eastern exposure. Make sure the system is operating properly including head operation and checking for any line leaks.

Dormant watering

For homeowners deciding not to do a full season of watering, the lawn will look different as the growing season moves along. "They will get that spring flush of growth like everyone else," Hentschel says. "That settles down as the drier late June weather arrives. This is where our lawn maintenance schedule begins to change.” 

Not watering means there’s less mowing, but the one-third rule still applies. Without watering, no summer fertilizers are needed. The lawn naturally will go dormant during hot summer months until cooler weather and rains come back.

Here comes the difference in the two lawn care versions. While the lawn is dormant and to keep from having dead grass in the fall, enough watering must be done to keep the plant crowns hydrated until that better weather shows up.

“This will not turn the lawn green yet will keep it alive,” Hentschel says. About one-half inch of water every few weeks is enough. Once growth resumes naturally, so can the fall fertilization along with increased mowing.

Source: Richard Hentschel, Educator, University of Illinois Extension Horticulture 

University of Illinois Extension is the outreach effort of the University of Illinois at Urbana-Champaign, offering educational programs to residents of all of Illinois' 102 counties and far beyond. Illinois Extension provides practical education you can trust to help people, businesses, and communities solve problems, develop skills, and build a better future. Through our Agriculture and Natural Resources programs, Illinois Extension supports the economic viability and environmental sustainability of natural and managed landscapes and productive lands in Illinois. Horticulture program educators provide research-based information and training about gardening, fruits and vegetables, flowers, insects and diseases, composting, landscaping, and more.