Illinois vegetable planting calendar 2027: frost dates and when to plant
In Illinois, the average last spring frost is April 15 in Springfield and April 10 in Chicago (NOAA 1991-2020 normals). Below are planting dates for Springfield and Chicago for 27 common vegetables and herbs, worked out the way the Rowtime app does it: NOAA's average frost dates for the nearest weather station, with the planting rules of state extension guides. Dates are for the 2027 season.
Rowtime: Garden Planner works these dates out for your own ZIP code in Illinois, shows where each one comes from, and recalculates when a planting slips. Get Rowtime on the App Store.
Dates are estimates. Check your local extension office before you plant, and use your own frost records if you have them. Dates shift by a week or more within a state, so pick the city closest to your conditions.
Springfield
When to plant tomatoes in Springfield?
In Springfield, Illinois, the average last spring frost is April 15 and the average first fall frost is October 22 (NOAA 1991-2020 normals, SPRINGFIELD #2 station, 2.4 km from ZIP 62701). For tomatoes, start seeds indoors March 20 to May 26 and plant out seedlings April 30 to July 24, following University of Maryland Extension (Home & Garden Information Center) and Purdue University Extension. Dates are for the 2027 season; sources last checked October 24, 2026.
Frost dates for Springfield (62701)
- Last spring frost: Apr 15 on average, Apr 30 for a 10% risk of a later frost.
- First fall frost: Oct 22 on average, Oct 9 for a 10% risk of an earlier frost.
- USDA hardiness zone 6a (PRISM 2023 listing).
| Crop | When |
|---|---|
| Beet | Sow outdoors: Apr 2 to Apr 16 Sow outdoors for fall: Aug 14 to Sep 11 |
| Broccoli | Start seeds indoors: Feb 27 to Apr 5 Plant out seedlings: Mar 19 to Apr 2 Plant out seedlings for fall: Aug 14 to Sep 11 |
| Cabbage | Start seeds indoors: Feb 20 to Mar 19 Plant out seedlings: Mar 19 to Apr 2 Plant out seedlings for fall: Aug 14 to Sep 11 |
| Carrot | Sow outdoors: Apr 2 to Apr 16 |
| Cauliflower | Start seeds indoors: Mar 6 to Apr 5 Plant out seedlings: Apr 2 to Apr 16 Plant out seedlings for fall: Jun 22 to Jul 22 |
| Cucumber | Sow outdoors: May 14 to Aug 13 |
| Eggplant | Start seeds indoors: Apr 6 to May 5 Plant out seedlings: May 14 to Jul 24 |
| Green onion | Plant onion sets: Mar 19 to Apr 2 Plant out seedlings for fall: Aug 14 to Sep 11 |
| Kale | Sow outdoors: Mar 19 to Apr 2 Sow outdoors for fall: Aug 14 to Sep 11 |
| Lettuce | Sow outdoors: Apr 2 to Apr 16 Sow outdoors for fall: Aug 14 to Sep 11 |
| Melon and watermelon | Sow outdoors: May 14 to Jul 14 |
| Okra | Plant out seedlings: May 14 to Aug 18 |
| Onion | Plant onion sets: Mar 19 to Apr 2 |
| Pea | Sow outdoors: Mar 19 to Apr 2 |
| Pepper | Start seeds indoors: Mar 20 to Apr 19 Plant out seedlings: May 14 to Jul 24 |
| Potato | Plant seed potatoes: Mar 19 to Apr 2 |
| Snap bean | Sow outdoors: Apr 30 to Aug 23 |
| Spinach | Sow outdoors: Mar 19 to Apr 2 Sow outdoors for fall: Aug 14 to Sep 11 |
| Summer squash | Sow outdoors: May 14 to Aug 23 |
| Sweet corn | Sow outdoors: Apr 30 to Jul 24 |
| Sweet potato | Sprout slips indoors: Apr 20 to May 19 Plant out slips: May 14 to Jun 14 |
| Tomato | Start seeds indoors: Mar 20 to May 26 Plant out seedlings: Apr 30 to Jul 24 |
| Winter squash and pumpkin | Sow outdoors: May 14 to Jul 14 |
| Basil | Plant outdoors: May 19 to Aug 18 |
| Cilantro | Sow outdoors: Feb 19 to Apr 18 Sow outdoors for fall: Aug 30 to Sep 13 |
| Dill | Sow outdoors: Apr 3 to Apr 18 Sow outdoors for fall: Jul 15 to Aug 29 |
| Parsley | Sow outdoors: Apr 6 to May 5 Plant outdoors for fall: Jul 15 to Sep 13 |
Chicago
When to plant tomatoes in Chicago?
In Chicago, Illinois, the average last spring frost is April 10 and the average first fall frost is November 5 (NOAA 1991-2020 normals, CHICAGO NORTHERLY IS station, 3.4 km from ZIP 60602). For tomatoes, start seeds indoors March 15 to May 21 and plant out seedlings April 25 to August 7, following University of Maryland Extension (Home & Garden Information Center) and Purdue University Extension. Dates are for the 2027 season; sources last checked October 24, 2026.
Frost dates for Chicago (60602)
- Last spring frost: Apr 10 on average, Apr 25 for a 10% risk of a later frost.
- First fall frost: Nov 5 on average, Oct 24 for a 10% risk of an earlier frost.
- USDA hardiness zone 6b (PRISM 2023 listing).
| Crop | When |
|---|---|
| Beet | Sow outdoors: Mar 28 to Apr 11 Sow outdoors for fall: Aug 29 to Sep 26 |
| Broccoli | Start seeds indoors: Feb 22 to Mar 31 Plant out seedlings: Mar 14 to Mar 28 Plant out seedlings for fall: Aug 29 to Sep 26 |
| Cabbage | Start seeds indoors: Feb 15 to Mar 14 Plant out seedlings: Mar 14 to Mar 28 Plant out seedlings for fall: Aug 29 to Sep 26 |
| Carrot | Sow outdoors: Mar 28 to Apr 11 |
| Cauliflower | Start seeds indoors: Mar 1 to Mar 31 Plant out seedlings: Mar 28 to Apr 11 Plant out seedlings for fall: Jul 6 to Aug 5 |
| Cucumber | Sow outdoors: May 9 to Aug 27 |
| Eggplant | Start seeds indoors: Apr 1 to Apr 30 Plant out seedlings: May 9 to Aug 7 |
| Green onion | Plant onion sets: Mar 14 to Mar 28 Plant out seedlings for fall: Aug 29 to Sep 26 |
| Kale | Sow outdoors: Mar 14 to Mar 28 Sow outdoors for fall: Aug 29 to Sep 26 |
| Lettuce | Sow outdoors: Mar 28 to Apr 11 Sow outdoors for fall: Aug 29 to Sep 26 |
| Melon and watermelon | Sow outdoors: May 9 to Jul 28 |
| Okra | Plant out seedlings: May 9 to Sep 1 |
| Onion | Plant onion sets: Mar 14 to Mar 28 |
| Pea | Sow outdoors: Mar 14 to Mar 28 |
| Pepper | Start seeds indoors: Mar 15 to Apr 14 Plant out seedlings: May 9 to Aug 7 |
| Potato | Plant seed potatoes: Mar 14 to Mar 28 |
| Snap bean | Sow outdoors: Apr 25 to Sep 6 |
| Spinach | Sow outdoors: Mar 14 to Mar 28 Sow outdoors for fall: Aug 29 to Sep 26 |
| Summer squash | Sow outdoors: May 9 to Sep 6 |
| Sweet corn | Sow outdoors: Apr 25 to Aug 7 |
| Sweet potato | Sprout slips indoors: Apr 15 to May 14 Plant out slips: May 9 to Jun 28 |
| Tomato | Start seeds indoors: Mar 15 to May 21 Plant out seedlings: Apr 25 to Aug 7 |
| Winter squash and pumpkin | Sow outdoors: May 9 to Jul 28 |
| Basil | Plant outdoors: May 14 to Aug 13 |
| Cilantro | Sow outdoors: Feb 14 to Apr 13 Sow outdoors for fall: Sep 13 to Sep 27 |
| Dill | Sow outdoors: Mar 29 to Apr 13 Sow outdoors for fall: Jul 29 to Sep 12 |
| Parsley | Sow outdoors: Apr 1 to Apr 30 Plant outdoors for fall: Jul 29 to Sep 27 |
Sources
Planting rules, in the order Rowtime tries them here:
- Purdue University Extension, Indiana Vegetable Planting Calendar (HO-186-W). Checked October 20, 2026.
- University of Maryland Extension (Home & Garden Information Center), Vegetable Planting Calendar for Central Maryland. Checked October 24, 2026.
- NC State Extension, Central North Carolina Planting Calendar for Annual Vegetables, Fruits, and Herbs (AG-756-01). Checked October 21, 2026.
Frost dates, locations and zones:
- NOAA National Centers for Environmental Information, U.S. Climate Normals 1991-2020 annual/seasonal (freeze probabilities).
- U.S. Census Bureau, 2025 Gazetteer Files: ZIP Code Tabulation Areas.
- PRISM Group, Oregon State University / USDA ARS, 2023 USDA Plant Hardiness Zone Map ZIP code listings. PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed 20 Oct 2026.
How the dates are worked out: a guide's rule such as "two weeks after the last frost" is applied to the station's NOAA date. Purdue's dates are 10% dates, so they are counted from the station's 10% date. When a guide gives no last date, the window closes early enough for the crop's longest days to harvest before the first fall frost. When a guide gives no first date for a fall planting, no fall window is shown. "Season too short" means the guide's window would close before it opens at this station's frost dates.
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