When Should Grass Seed Be Planted in Illinois? – Beginners with little knowledge or expertise may believe that grass seed may be planted at any time. In contrast, each location has a distinct planting window for lawn grasses based on temperature, soil, and other variables.
When should I fertilize my Illinois lawn?
Regarding Overseeding a Lawn – The optimum time to overseed a lawn in Illinois is late summer/early fall (late August to mid-September). The high soil temperatures at this time of year promote optimal seed germination, while the lower air temperatures favor grass growth. 
Should your lawn be reseeded in the spring?
Although the optimal time to overseed or reseed your lawn is in the spring or fall, overseeding is identical to reseeding in most other regards. Using the seed of new and improved turfgrass varieties will increase the lawn’s resistance to diseases, insects, and drought.
As an Amazon Associate and associate of other programs, I get commissions on orders that qualify. After overseeding, fresh grass should be left alone for at least two to three weeks. This will let the young, weak roots to become established before being disturbed by the mowing process.
Resting the young seedlings is essential for effective overseeding. Overseeding might be the solution for your thin and worn grass. Overseeding is the practice of cultivating fresh grass seeds. It can be difficult to identify when to cut young grass after overseeding, which makes overseeding tough at times.
This tutorial will help you understand the significance of time when it comes to mowing fresh grass after overseeding, as well as the specifics of the overseeding procedure. 
