Quick planting window
| Start indoors | March to April |
|---|---|
| Transplant | May to June |
| Sow seeds | Usually not recommended for this crop in a short-season garden |
| Estimated harvest | July to August |
| Risk | Medium risk |
Month calendar
Scan the year by month to see seed starting, sowing, transplanting, and harvest timing.
Tomato is frost sensitive. Wait until the conservative transplant or sowing window for Illinois.
Next: ZIP code personalization
This is a state-level planning window based on typical frost timing and crop rules. Use local Extension guidance or a ZIP code frost-date tool before planting.
Planning notes
Covered crops
15
Covered states
Illinois
Frost window
April to May / September to October
Northern Illinois is later in spring and earlier in fall than southern Illinois.
Tomato growing notes
The calendar window is only the first step. These growing details affect survival, plant vigor, and harvest quality.
Sun
Full sun, ideally 6-8+ hours.
Soil
Rich, well-drained soil with compost.
Spacing
18-24 inches for compact types; 24-36 inches for vigorous vines.
Container
Use a 5+ gallon container for patio types; larger is better.
Watering
Water deeply and consistently; avoid wetting leaves late in the day.
Common mistake
Transplanting before nights are warm enough.
Beginner tip
Harden seedlings off for 7-10 days before planting outside.
Month window table
| Crop | Spring transplant / sow | Spring harvest | Fall transplant / sow | Fall harvest |
|---|---|---|---|---|
| Tomato | May to June | July to August | July to August | September to October |
| Cucumber | May to June | July to August | July to August | September to October |
| Pepper | May to June | August to September | June to July | September to October |
| Lettuce | April to May | May to June | August to September | September to October |
| Carrot | April to May | June to July | August | October to November |
| Spinach | March to April | May to June | August to September | September to October |
| Green Bean | May to June | July to August | August | September to October |
| Zucchini | May to June | June to July | July to August | September to October |
| Potato | April to May | July to August | July to August | October to November |
| Broccoli | April to May | June to July | July to August | September to October |
| Kale | April to May | May to June | August | September to October |
| Onion | March to April | July to August | July to August | October to November |
| Garlic | December to January | August to September | August to September | April to May |
| Corn | May to June | July to August | July to August | October to November |
| Radish | March to April | April to May | August to September | September to October |
Sources and limits
This page uses Illinois state-level frost windows, USDA zone ranges, and crop rules for planning. It does not replace local Extension or county-level guidance.
FAQ
When should I start spring planting in Illinois?
Use the last frost window, usually April to May, as the planning anchor. Hardy crops can start earlier; frost-sensitive crops should wait for warmer soil and nights.
When should I plan fall planting in Illinois?
Count backward from the first frost window, usually September to October. Long-season and frost-sensitive crops need more lead time.
Which vegetables are easiest in Illinois?
Start with easier crops such as cucumber, lettuce, spinach, green bean, zucchini. The best choice still depends on season and local conditions.
How should I handle summer heat in Illinois?
Summer heat is less severe than in hot southern states, but cool-season crops still benefit from avoiding the hottest weeks.
Can I grow a fall garden in Illinois?
Yes. Use September to October as the cutoff anchor and leave buffer time for germination, transplant shock, and maturity.
Do local differences matter?
Northern Illinois is later in spring and earlier in fall than southern Illinois.
Does this replace local Extension guidance?
No. Use this as a first-pass planning calendar, then confirm with local Extension, county guidance, or a ZIP-code frost-date tool before planting.