Illinois Extension says that due to the urban heat effect, the Chicago area has a warmer zone than the rest of Northern Illinois and may be closer to central Illinois dates.
Regional guide
Chicago Area Illinois Vegetable Planting Guide
Illinois Extension guide for Chicago-area gardeners using Northern Illinois planting windows with an urban heat caveat against Central Illinois dates.
Regional timing
Current regional planting plan
Illinois Extension guide for Chicago-area gardeners using Northern Illinois planting windows with an urban heat caveat against Central Illinois dates.
Source-backed timing
Illinois Extension when to plant
Chicago Area IL
5 climate signals
Source
source cues
Local
conditions
- Illinois Extension lists Northern Illinois median spring frost-free dates as April 8-29 and Central Illinois median dates as April 8-15.
- Illinois Extension says that due to the urban heat effect, the Chicago area has a warmer zone than the rest of Northern Illinois and may be closer to central Illinois dates.
- The source says last freezes can happen before or after the median frost-free date ranges, so Chicago gardeners should still check frost-date maps, plant tags, and seed packets.
- Catalog priority
- 20 priority crops 20 catalog examples
- Climate checks
- 5 climate signals 6 planning notes
- Timing basis
- Use regional source signals source guidance first
Provider Bush Bean, Roma Tomato, Black Seeded Simpson Lettuce, Bloomsdale Spinach
For bush beans, compare Northern Illinois May 24 to June 30 or July 30 to Aug. 14 with Central Illinois May 10 to June 15 or July 15 to 30.
Calendar
Convert regional timing into dated sowing, transplant, and harvest jobs.
Frost dates
Keep hardiness zone context separate from local first and last frost dates.
All regions
Compare this guide with the broader regional atlas.
Illinois
An Illinois vegetable guide for Northern, Central, and Southern planting-date columns, frost-free ranges, and seasonal crop timing.
Climate signals
- Illinois Extension lists Northern Illinois median spring frost-free dates as April 8-29 and Central Illinois median dates as April 8-15.
- Illinois Extension says that due to the urban heat effect, the Chicago area has a warmer zone than the rest of Northern Illinois and may be closer to central Illinois dates.
- The source says last freezes can happen before or after the median frost-free date ranges, so Chicago gardeners should still check frost-date maps, plant tags, and seed packets.
- The Illinois planting chart says two dates mean the crop can be planted twice for both a summer and fall crop.
- The source separates annual vegetable timing from USDA hardiness zones because zones mostly apply to perennial landscape plants.
Planning notes
- Use the Northern Illinois table as the conservative starting point for greater Chicago gardens, then compare Central Illinois rows for warmer urban-core and near-lake microclimates instead of assuming one metro-wide date.
- For bush beans, compare Northern Illinois May 24 to June 30 or July 30 to Aug. 14 with Central Illinois May 10 to June 15 or July 15 to 30.
- For tomatoes, compare Northern Illinois May 24 to June 15 with Central Illinois May 10 to June 1, and wait for warm-season transplant conditions rather than planting by hardiness zone.
- For lettuce, compare Northern Illinois April 15 to May 15 and July 15 to Sept. 15 with Central Illinois April 1 to 30 and July 1 to Aug. 31.
- Use cool-season rows such as spinach, radish, mustard, turnip, broccoli, cabbage, kale, beets, carrots, and chard for spring and fall planning, then check maturity days against first-frost risk.
- Use these priority catalog links as crop-level examples for the Illinois Extension timing table, not Illinois Extension cultivar recommendations.
Catalog crop examples
These catalog entries match crops covered by the regional timing source; variety-specific details remain tied to each seed entry's own source.
- Provider Bush Bean Vegetable · Warm · 50 days
- Roma Tomato Vegetable · Warm · 76 days
- Black Seeded Simpson Lettuce Vegetable · Cool · 45 days
- Bloomsdale Spinach Vegetable · Cool · 42 days
- French Breakfast Radish Vegetable · Cool · 28 days
- Southern Giant Curled Mustard Vegetable · Cool · 45 days
- Purple Top White Globe Turnip Vegetable · Cool · 55 days
- Waltham 29 Broccoli Vegetable · Cool · 74 days
- Golden Acre Cabbage Vegetable · Cool · 64 days
- Lacinato Kale Vegetable · Cool · 60 days
- Detroit Dark Red Beet Vegetable · Cool · 58 days
- Danvers 126 Carrot Vegetable · Shoulder · 70 days
- Bright Lights Swiss Chard Vegetable · Shoulder · 55 days
- Golden Bantam Sweet Corn Vegetable · Warm · 80 days
- Marketmore 76 Cucumber Vegetable · Warm · 58 days
- Black Beauty Eggplant Vegetable · Warm · 80 days
- California Wonder Pepper Vegetable · Warm · 72 days
- Small Sugar Pumpkin Vegetable · Warm · 100 days
- Waltham Butternut Squash Vegetable · Warm · 95 days
- Sugar Baby Watermelon Vegetable · Warm · 80 days
Related regional guides
- Illinois Three-Region Vegetable Garden An Illinois vegetable guide for Northern, Central, and Southern planting-date columns, frost-free ranges, and seasonal crop timing.
- McHenry County Illinois Planting Guide Illinois Extension McHenry County guide for seven vegetable planting windows, transplant labels, and fall harvest timing.
Source: Illinois Extension when to plant