University of Illinois Extension

Late Summer and Fall Lawn Care

Depending on where you live in Illinois, late summer and fall lawn care will differ, said Richard Hentschel, U of I Extension specialist.

“Areas receiving plenty of water during the season will have less lawn recovery issues than those parts of the state that have experienced periods of dry weather during June and July and into August,” said Richard Hentschel

Now is a good time to do a weed inventory and determine your best management strategy, he noted.
“Are your main weeds annuals which will die with the first frosts or has your lawn been invaded by the germination and growth of perennial weeds like dandelions?” he asked. “Areas that have had considerable annual crabgrass will need to be reseeded to help cover the ground that was previously home to the annuals. You may need to modify the soil to encourage good seedling establishment or if your soil is in good shape, just top dress and then reseed.

“If annuals make up the biggest problem, you have a ‘do over’ with the opportunity to try again next spring to keep them from invading your lawn. You will still need to repair any damage caused by the annuals this fall. If you don’t, you leave that open area for more annuals to sprout next spring.”

If your weed inventory reveals lots of seedling broadleaf weeds like dandelions and plantains that have grown throughout the season, be sure you control them yet this fall, eliminating them now and lessening the need for a spring dandelion treatment, when our vegetables and flowers in nearby beds are more prone to damage.

“A good indicator for compacted soils is knotweed,” he said. “This is a common condition along the driveway apron where the car tire runs just off the driveway as you pull in or back out.

“You will have to relieve that soil compaction for your lawn to grow into that area and keep the weeds from reestablishing after the weed control treatment. We are not going to stop driving, yet we can be sure to pull ahead a little more before turning in or backing out a little farther before turning the wheel as we leave the driveway.”

If your lawn suffered through a dry period and went dormant, it will take about two weeks once you start to water or for cooler, wetter weather returning before the lawn will start to green up.

“During those dry periods, some of the grass may have actually died,” he said. “Those thin spots will need to be top dressed and reseeded to establish a thick lawn again that will resist weed establishment.”

Lawn disease is another possibility this summer. The weather has promoted lawn diseases longer than normal and has resulted in thinned-out lawns.

“When you are over-seeding or reseeding be sure to use the newer improved grasses for your area that have that disease resistance already built in to their DNA,” said Hentschel. “Buy a blend of several grasses over a single variety. This will provide a better chance of always having a green lawn without a disease outbreak. Over time those hybrid varieties will continue to spread and establish in your lawn as the weaker grasses die from leaf diseases.”

Besides the weather, mowing too short, under or overwatering can also promote lawn diseases.

“You also may have had grub damage in your lawn this summer,” he said. “Check for grubs and only treat if necessary. Treat for white grubs in the late spring or early summer, eliminating them from causing damage during August and September. A word of caution here – earthworms eat and digest organic matter and are present in your lawn. Repeated use of soil insecticides will also kill earthworms.

“How you treat and manage your lawn this fall will be reflected in how well in overwinters and how good it looks next spring.”