If your lawn looks thinner every year, compacted soil is a likely reason. Clay soil, foot traffic, mowers and heavy rain squeeze out the air that grass roots need. Aeration and overseeding are the most effective way to turn that around in a cool-season lawn.
This site celebrates local lawn care companies doing great work, and one of our first spotlights goes to LawnWorks. The family-owned company started as LawnWorks of Joliet in 1988 and today serves Joliet and the southwest suburbs of Chicago from Crest Hill, Illinois.
Their lawn aeration service is a big part of how they help homeowners in towns like Naperville, Plainfield, Bolingbrook, Orland Park and New Lenox build thicker, healthier lawns on Chicago-area clay.
Here's what to know about aerating and overseeding a cool-season lawn.
Why cool-season lawns need it
Kentucky bluegrass, tall fescue and perennial ryegrass make up most lawns across the Midwest and North. They grow best in spring and fall, and they slow down or go dormant in summer heat. Over the years, summer stress, insects and disease thin them out, and compacted soil keeps them from filling back in.
Why fall is the best time
Late August through early October is the ideal window. Soil is still warm, which helps seed sprout quickly. Air temperatures are cooler, which is easier on new grass. And weed pressure is lower than in spring, so new seedlings face less competition.
Spring seeding can work, but new grass often struggles through its first summer, and spring crabgrass pre-emergent can stop grass seed from sprouting.
Core aeration does the heavy lifting
Core aeration pulls thousands of small plugs of soil out of the lawn. That relieves compaction, lets water and fertilizer reach the roots, and gives new seed protected pockets to sprout in. The plugs left on the lawn break down on their own in a week or two.
Choosing the right seed
A good seed blend is matched to your yard. Sunny lawns usually do well with a bluegrass and ryegrass blend. Shady areas need fine fescues or a shade-tolerant tall fescue. Mixing seed types gives the lawn better resistance to disease and drought.
Watering after seeding
New seed has to stay moist to sprout. For the first two weeks, light watering once or twice a day keeps the top inch of soil damp. Once seedlings are up, water less often but more deeply to push roots down.
Questions to ask a lawn care company
- Do you core aerate, and how many passes do you make?
- What seed blend will you use for my sun and shade?
- When should I start mowing the new grass?
- Will you mark my sprinkler heads and invisible dog fence?
- How should I adjust my watering after seeding?
Aerating and overseeding every fall or two is one of the best things you can do for a cool-season lawn.