University of Illinois Extension
Bruce Spangeberg

These articles are written to apply to the northeastern corner of Illinois. Problems and timing may not apply outside of this area.

Stateline Yard & Garden

Preparing Lawns for Summer Heat

June 8, 2000

High temperatures and lack of rain are two problems lawns face during the summer months. Certainly rainfall has not been lacking recently in northern Illinois, and temperatures were cool as June began. As we advance into summer, conditions most likely will be stressful for lawns, so it pays to prepare for it.

Perhaps the single most important way to prepare lawns for hot weather is to mow higher. Mow at heights around three inches or even slightly higher. If in doubt, set the mower as high as it will go. Grass maintained at a higher height of cut usually develops deeper roots and dries out slower than closely mowed turf. Even though most lawns are currently still growing at a rapid pace from all the rain, growth usually will slow down as the weather gets drier and hotter.

The other main concern of summer is to water lawns properly. With the heavy rains hitting most of northern Illinois in June, watering lawns is probably not on the minds of most homeowners! But remember there is plenty of summer yet ahead.

The vast majority of lawns in our area consist of cool-season lawn grasses such as Kentucky bluegrass, perennial ryegrass, and fine fescue. These grasses naturally slow down and may go dormant in the heat of summer. Decide to water lawns all summer as needed to keep them green or let lawns go dormant. Do not allow lawns to turn brown and then water them back to a green condition, as this depletes energy reserves and stresses the plant.

Water lawns deeply and infrequently, applying about 1 to 1 1/2 inches per application, depending on site variables. Water early in the day if at all possible. Water should soak down into the soil. If allowed to go dormant, lawns only need about 1/4 to 1/2 inch of water every 2 to 3 weeks to keep root and crown tissue alive. Once more favorable cooler and drier weather returns, the lawn should break dormancy and green-up again.

It's best to hold off until later in the season for most other lawn care practices, including fertilizing, seeding, thatch control, and applying weed killers. The period from late August through early September is ideal for many of these practices. For now, help your lawn by proper mowing, watering, and keeping foot and vehicle traffic off the grass as much as possible during the heat of the upcoming summer months.


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