LawnWeather

Illinois Lawn Care Calendar

In Illinois, crabgrass preventer typically goes down between Mar 20 and May 6: first in Carbondale, last in Rockford. Below are typical fertilizer, seeding and frost dates for Chicago, Peoria, Springfield, Carbondale, Naperville, Joliet, Rockford and Champaign, from 2016–2025 weather data. Enter your ZIP code for this year's timing.

When to apply pre-emergent in Illinois

Typically between Mar 20 and May 6, depending on where you live. The window opens first in Carbondale (around Mar 20) and last in Rockford (around Apr 19). Apply when soil reaches 50°F, before it stays above 55°F.

CityCrabgrass preventer window
CarbondaleMar 20 – Apr 16
SpringfieldApr 8 – Apr 24
PeoriaApr 10 – Apr 25
ChampaignApr 10 – Apr 26
JolietApr 18 – May 1
ChicagoApr 19 – May 13
NapervilleApr 19 – May 8
RockfordApr 19 – May 6

Cool-season lawn calendar

Lawns across Illinois are mostly cool-season grass (tall fescue, Kentucky bluegrass, perennial ryegrass).

CitySpring fertilizerOverseeding & seedingFall fertilizer
ChicagoMay 6 – Jun 10Aug 24 – Oct 13Sep 10 – Nov 9
PeoriaApr 18 – May 23Aug 6 – Sep 25Sep 9 – Nov 5
SpringfieldApr 17 – May 22Aug 7 – Sep 26Sep 9 – Nov 5
CarbondaleApr 9 – May 14Aug 16 – Oct 5Sep 15 – Nov 18
NapervilleMay 1 – Jun 5Aug 11 – Sep 30Aug 25 – Nov 1
JolietApr 24 – May 29Aug 13 – Oct 2Sep 8 – Nov 1
RockfordApr 29 – Jun 3Aug 7 – Sep 26Aug 24 – Nov 1
ChampaignApr 19 – May 24Aug 6 – Sep 25Sep 3 – Nov 5

Frost dates in Illinois

CityLast spring frostFirst fall frost
ChicagoApr 6Nov 7
PeoriaApr 21Oct 20
SpringfieldApr 17Oct 21
CarbondaleApr 9Oct 30
NapervilleApr 27Oct 25
JolietApr 24Oct 27
RockfordApr 27Oct 21
ChampaignApr 22Oct 20

Median dates, 2016–2025. A dash means frost does not occur in most years.

Frequently asked questions

When should I put down pre-emergent in Illinois?

Typically between Mar 20 and May 6, depending on where you live. The window opens first in Carbondale (around Mar 20) and last in Rockford (around Apr 19). Apply when soil reaches 50°F, before it stays above 55°F.

When is the best time to seed grass in Illinois?

Early fall is best for cool-season grass (tall fescue, Kentucky bluegrass, perennial ryegrass): typically from Aug 6 to Oct 13 across Illinois, while soil cools from 65°F toward 50°F.

What type of grass grows in Illinois?

Most lawns in Illinois are cool-season grass (tall fescue, Kentucky bluegrass, perennial ryegrass).

Lawn care guides

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