University of Illinois Extension

Summer Lawn Care

Homeowners are having the annual overthe- fence discussion with their neighbors about letting the lawn go dormant or not, says Richard Hentschel, a U of I Extension horticulturist.

“Our cool-season grasses will naturally go dormant as the summer heat and lack of rainfall triggers that dormancy,” said Hentschel. “What went wrong in 2012 is that the extended drought did not supply even the minimal rains that the crown of the grass plant needed to remain hydrated and able to return to grow again in the late summer into fall as we expected. In 2013, there has been a lot of reseeding and re-sodding to get the lawns back into shape.

“This unfortunate weather did provide an opportunity to improve the lawn as we rebuilt it by using grass seed that is more disease-resistant and more vigorous than those seeds used even five or 10 years ago. Weed populations have also been higher, since the lawns are thinned and not nearly as competitive as they typically have been.”

There are several ways to continue to aid in the lawns recovery that are really variations of what we are already used to doing. As the summer weather comes along, mowing the lawn at a higher mower setting leaves a longer grass blade that can produce more nutrients for the roots and at the same time shade the soil, keeping those roots cooler.

“Moving the blade up just takes a few minutes and the results are long lasting,” he said. “Another mower-related item is to make sure the mower blade is sharp, doing a better job of cutting the grass blade and not tearing or shredding. If you are able, sharpen the blade at least a couple times during the growing season. That taller grass blade also helps the lawn compete better against existing weeds and prevents others from germinating from seed.”

Mowing frequency also helps maintain a better looking lawn. If the lawn is mowed more often, the grass clippings can often times be left on the lawn and that can return one pound of nitrogen per 1000 square feet or more to the soil. That is free nitrogen that does not cost anything and clippings that are not collected and put out for collection.

“Now back to the decision to water or not,” he said. “If the desire is to have the lawn remain green all summer, then a commitment to provide enough water to keep it actively growing is key. Watering the lawn deeply will promote longer roots, this in turn allows the lawn to be more drought tolerant during brief dry periods. This also means that the lawn will use more fertilizer as well, no matter, if it is a commercial product or organic in nature.

“When the decision is to allow the lawns to go dormant, remember that even in a dormant state, the grass plant crowns will need to receive about 1/2 inch of water a couple of times a month even while the lawn is dormant and brown or straw-colored. The lawns will resume their fall growth once appropriate weather returns no matter what part of the state you live in. In summary, mow high, mow often with a sharp blade and water deeply when you do.”

Did you know?
Lawns requiring frequent pesticide use, in particular herbicides, may have an underlying problem that is causing the repeated invasions of pests such as weeds. Correcting the problem leads to a healthier lawn that can resist weed invasions.

To learn more about lawn care
Lawn Talk
Major Turf Insects & Diseases