Calendars by city / IL
Chicago, Illinois vegetable planting calendar
Planting windows for Chicago, Illinois built from the NOAA 1991–2020 freeze normals at CHICAGO OHARE INTERNATIONAL AIRPORT, IL US (station USW00094846), not from a hardiness zone.
Chicago, Illinois planting dates for 27 vegetables
The same windows as a table
Each row applies a published extension rule to the frost dates above. Hardy crops go out 2–4 weeks before the last frost; semi-hardy crops 0–2 weeks before; tender crops around the frost date; very tender crops 2 or more weeks after. The last fall planting date counts the crop's days to harvest back from the first fall frost. The rules and their sources are on the methodology page.
| Crop | Frost class | Start seeds indoors | Plant outdoors | Last fall planting | Days to harvest |
|---|---|---|---|---|---|
| Beets | Semi-hardy | — (direct sow) | Direct sow: Apr 8 – Apr 22 | Aug 27 | 60 |
| Broccoli | Hardy | Feb 4 – Mar 4 | Transplant: Mar 25 – Apr 8 | Aug 29 | 65 (from transplant) |
| Cabbage | Hardy | Feb 4 – Mar 4 | Transplant: Mar 25 – Apr 8 | Aug 9 | 85 (from transplant) |
| Carrots | Semi-hardy | — (direct sow) | Direct sow: Apr 8 – Apr 22 | Aug 17 | 70 |
| Cauliflower | Semi-hardy | Feb 18 – Mar 18 | Transplant: Apr 8 – Apr 22 | Aug 22 | 65 (from transplant) |
| Kohlrabi | Hardy | — (direct sow) | Direct sow: Mar 25 – Apr 8 | Sep 13 | 50 |
| Lettuce (leaf) | Hardy | — (direct sow) | Direct sow: Mar 25 – Apr 8 | Sep 3 | 60 |
| Onions (green) | Hardy | — (direct sow) | Direct sow: Mar 25 – Apr 8 | Sep 3 | 60 |
| Onions (dry, from seed) | Hardy | — (direct sow) | Direct sow: Mar 25 – Apr 8 | Jul 15 | 110 |
| Onions (dry, from sets) | Hardy | — (direct sow) | Plant sets: Mar 25 – Apr 8 | Jul 15 | 110 |
| Parsnips | Semi-hardy | — (direct sow) | Direct sow: Apr 8 – Apr 22 | Aug 17 | 70 |
| Peas | Hardy | — (direct sow) | Direct sow: Mar 25 – Apr 8 | Aug 29 | 65 |
| Potatoes | Semi-hardy | — (direct sow) | Plant seed potatoes: Apr 8 – Apr 22 | Jun 23 | 125 |
| Radishes | Hardy | — (direct sow) | Direct sow: Mar 25 – Apr 8 | Oct 3 | 30 |
| Spinach | Hardy | — (direct sow) | Direct sow: Mar 25 – Apr 8 | Sep 23 | 40 |
| Swiss chard | Semi-hardy | — (direct sow) | Direct sow: Apr 8 – Apr 22 | Aug 27 | 60 |
| Turnips | Hardy | — (direct sow) | Direct sow: Mar 25 – Apr 8 | Sep 13 | 50 |
| Snap beans | Tender | — (direct sow) | Direct sow: Apr 22 – Apr 29 | Aug 20 | 60 |
| Cantaloupe | Very tender | Apr 15 – May 6 | Direct sow (or transplant): May 6 – May 20 | Jul 26 | 85 |
| Sweet corn | Tender | — (direct sow) | Direct sow: Apr 22 – Apr 29 | Jul 21 | 60–90 |
| Cucumbers | Tender | Apr 1 – Apr 15 | Direct sow (or transplant): Apr 22 – Apr 29 | Aug 25 | 55 |
| Eggplant | Very tender | Mar 4 – Apr 8 | Transplant: May 6 – May 20 | Aug 20 | 60 (from transplant) |
| Peppers | Very tender | Mar 11 – Apr 8 | Transplant: May 6 – May 20 | Aug 10 | 70 (from transplant) |
| Tomatoes | Very tender | Mar 18 – Apr 15 | Transplant: May 6 – May 20 | Aug 15 | 65 (from transplant) |
| Summer squash | Tender | Apr 1 – Apr 15 | Direct sow (or transplant): Apr 22 – Apr 29 | Aug 30 | 50 |
| Winter squash | Very tender | Apr 15 – May 6 | Direct sow (or transplant): May 6 – May 20 | Jul 11 | 100 |
| Watermelon | Very tender | Apr 15 – May 6 | Direct sow (or transplant): May 6 – May 20 | Jul 26 | 85 |
What the Chicago, Illinois frost-free season means for your choices
At 180 frost-free days, Chicago, Illinois gardeners should compare that number to the days-to-harvest column before buying seed. A crop whose days to harvest plus its transplant age is close to the season length needs either an early start indoors or a short-season variety.
- Hardy crops (peas, spinach, radishes, lettuce, broccoli, cabbage) can go in from about Mar 25 – Apr 8 and again for fall.
- Very tender crops (tomatoes, peppers, eggplant, melons, winter squash) should wait until May 6 – May 20; start tomato seeds indoors Mar 18 – Apr 15.
- Fall sowing is worthwhile only for the rows that show a separate fall date; for the others the spring window already covers the season.
Chicago, IL planting questions
When is the last frost in Chicago, Illinois?
The 50% probability date for the last spring 32°F reading at CHICAGO OHARE INTERNATIONAL AIRPORT, IL US is Apr 22, from the NOAA 1991–2020 climate normals. In half the years on that record the last frost came later than that date, so tender crops are safer a week or two after it. The last 28°F hard freeze averages Apr 11.
When can I plant tomatoes in Chicago, Illinois?
Tomatoes are a very tender crop, so the Colorado State Extension rule puts them out 2 or more weeks after the last spring frost: May 6 – May 20 in Chicago, Illinois. Start the seeds indoors Mar 18 – Apr 15, which is 5 to 7 weeks before that transplant window.
How long is the growing season in Chicago, Illinois?
Chicago, Illinois averages 180 frost-free days, between the 50% last spring frost on Apr 22 and the 50% first fall frost on Oct 19 at CHICAGO OHARE INTERNATIONAL AIRPORT, IL US. Check a variety's days to harvest against that number before buying seed.
When should I start seeds indoors in Chicago, Illinois?
The earliest indoor sowing on this calendar is broccoli and cabbage at Feb 4 – Mar 4. Hardy crops are transplanted out Mar 25 – Apr 8 here, and each crop's indoor window is simply its outdoor window minus the transplant age published by Colorado State Extension, so nothing starts earlier than that.
What can I plant in fall in Chicago, Illinois?
The crops with a separate fall sowing here, latest first, are radishes, spinach, kohlrabi, turnips, lettuce (leaf) and onions (green), plus 21 more on the chart above. Each fall date counts the crop's days to harvest back from the first fall frost on Oct 19, plus an allowance for frost-tolerant crops that is our own assumption, not the source's.
Station data and limitations
| NOAA station | CHICAGO OHARE INTERNATIONAL AIRPORT, IL US (USW00094846) |
|---|---|
| Location | 41.995, -87.9336 · elevation 201.8 m |
| Last spring 32°F / 28°F (50%) | Apr 22 / Apr 11 |
| First fall 32°F / 28°F (50%) | Oct 19 / Oct 30 |
| Dataset | NOAA/NCEI U.S. Climate Normals 1991–2020, annual/seasonal product, data types ANN-TMIN-PRBLST/PRBFST-T32FP50 and T28FP50 |
| Retrieved | 2026-10-16 |
The normals describe the airport station, not your yard. They are averages of a 30-year record and say nothing about this year's weather. Watch the local forecast around the dates shown, and use soil temperature for warm-season crops, which the Colorado State guide treats as the better signal.
Nearby calendars
- Madison, Wisconsin — last spring frost May 2
- Grand Rapids, Michigan — last spring frost Apr 28
- Indianapolis, Indiana — last spring frost Apr 16
- Detroit, Michigan — last spring frost Apr 20
Read the method behind these dates: last frost date vs hardiness zone.