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Should I seed my lawn in Spring or Fall?

Lawn grub damage in need of repair and seeding

Lawn grub damage in need of repair and seeding

Seeding in Spring or Fall? A common question from homeowners.

One common question I am asked every Spring is, “Should I seed my lawn in Spring or Fall?” Many homeowners are eager to start thickening up their lawn as soon as they get a glimpse of good weather in early Spring. We sometimes still have a late March snow on the ground when the calls start coming in. My answer to their question is the ever-popular “It depends.” After explaining the pros and cons to many homeowners over the years, I’ve put my recommendation in writing on this page.

When is the best time to seed my Northern Illinois lawn?

Per the Illinois Department of Agriculture resources and many other university studies, the best time to seed in Northern Illinois is either Spring (the month of April), or early Fall (late August through the 2nd week of September). I am going to make it easier for you and recommend that you stick with early fall. Keep reading to find out why…

Seeding your lawn in Spring

Spring is a great time to seed your lawn, but there are more cons than pros when it comes to seeding this time of year. There are 2 main reasons why you should not seed your lawn in Spring: pre-emergent and summer.


As part of a normal lawn care program, pre-emergent is usually applied in the Spring to help prevent crabgrass and many other types of weeds. That is the good part about pre-emergent. The bad part about pre-emergent is, it also prevents good grass seed from germinating. If you put seed down all over your yard and then a pre-emergent is applied over the top of it, chances are, the seed will not germinate, or will experience a very low germination rate.


Grass plants depend on deep, healthy roots, and a tall, thick stand of grass blades to help it survive the stresses of Summer. Deep roots allow the grass to reach moisture that lies beyond the dried out top layer of soil. A tall and thick stand of grass blades help to shade the soil and prevent weeds from competing with the lawn. When you seed in the Spring, the new grass plants may come up very nicely after a few weeks, but under the soil, the roots will not yet be deep enough to survive Summer without a significant amount of irrigation from a sprinkler system. Unless you keep the seedlings watered all summer long and into early Fall, the chances of their survival is slim to none.

Seeding your lawn in Early Fall

If you seed your lawn in early Fall, the seedlings will have 9 to 10 months to develop deeper root systems before they have to experience their first Summer of hot and dry weather. Compare this to 1 or 2 months for a Spring seeding, and the chances of an early Fall seeding surviving to maturity are significantly greater. On top of that, you can still apply your pre-emergent in Spring and keep out the crabgrass and other weeds throughout the season.

Exceptions to my seeding recommendation

As with any rule or recommendation, there are always exceptions. For example, you may want to seed in the Spring if you had extensive drought or grub damage during the previous summer or fall. Pre-emergent works best on a thick stand of turf, but it does not work well in areas where there is exposed soil and not much grass. In cases like this, you have to compare the pros and cons. If you have a lot of bare spots, and you wait until Fall to seed, you may end up with a lot more weeds in those bare spots throughout the season. If you skip the pre-emergent and seed the bare areas in the Spring, you will prevent a lot of weeds in those bare areas, but you might experience some crabgrass or other weeds throughout the lawn.

Lawn seeding recommendation summary

To summarize, follow these recommendations when seeding your lawn in Northern Illinois:

Repair prior year damage or bare spots in Spring (month of April)

  • Apply pre-emergent for crabgrass and other weeds as part of your regular lawn care program.
  • Fix bare spots by roughing them up with a garden rake and adding fresh top soil and seed.
  • Keep the seeded areas and new seedlings watered throughout the Summer.

Over-seed the entire lawn in Early Fall (late August through early September)

  • Core aerate the entire lawn.
  • Over-seed the entire lawn.
  • You can also repair summer damage this time of year.

If you need any assistance with lawn care, core aeration, and over-seeding, please fill out the form on this page and I can provide you with a free quote and answer any other questions you might have.

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