When to plant in Illinois
Illinois spans USDA hardiness zones 5a-7a. Average last spring frost: late April (south)/mid May (north). Average first fall frost: late October (south)/mid October (north). This calendar is anchored to University of Illinois Extension's recommendations, with timing adjusted for the dominant climate zone of the state.
Illinois at a glance
| USDA hardiness zones | 5a-7a |
| Region | Midwest |
| Average last spring frost | late April (south)/mid May (north) |
| Average first fall frost | late October (south)/mid October (north) |
| Primary Extension service | University of Illinois Extension |
What grows particularly well in Illinois
These are the crops, ornamentals, and trees University of Illinois Extension highlights as well-suited to Illinois's climate:
- sweet corn
- tomato
- blueberry
- prairie dropseed
- coneflower
- little bluestem
Illinois planting calendar
Dates are approximate and based on the dominant USDA zone for the state. For zone-specific timing, use the zone finder by ZIP code and frost date lookup tools.
Spring planting (after last frost: late April (south)/mid May (north))
Cool-season vegetables (start 2-6 weeks before last frost outdoors): lettuce, spinach, peas, radishes, carrots, beets, kale, broccoli transplants, cabbage transplants.
Warm-season vegetables (after last frost, soil 60F+): tomato transplants, pepper transplants, beans (direct sow), cucumbers, squash, melons. See the seed starting timeline tool for indoor start dates.
Annual flowers (after last frost): zinnia, marigold, cosmos, sunflower, nasturtium.
Perennials, shrubs, trees: Plant in spring after soil thaws but before summer heat. Best window in Illinois: 4-6 weeks after last frost.
Summer (June - August)
Maintenance season for most Illinois gardens. Mulch heavily, water deeply (1 inch per week), pinch back mums for fall bloom, hand-pull weeds, harvest summer vegetables. Plant fall vegetable starts indoors by mid-July.
Fall planting (before first frost: late October (south)/mid October (north))
Cool-season vegetables (6-8 weeks before first frost): lettuce, spinach, radish, kale, broccoli, cabbage transplants. Per Penn State Extension, fall vegetable production can equal or exceed spring production with proper timing.
Spring-flowering bulbs: tulip, daffodil, allium, crocus, hyacinth. Plant 4-6 weeks before ground freezes. In Illinois: typically October-November.
Perennials, shrubs, trees: Fall is the best planting season for woody plants in most of Illinois - cooler temperatures + autumn rains reduce transplant stress. Plant 6+ weeks before first hard freeze.
Garlic: Plant cloves in October-November. Harvest the following July.
Winter (December - February)
Most of Illinois is in dormancy. Tasks: order seeds, plan next year, dormant prune fruit trees (February), order bare-root plants for spring delivery. Avoid foot traffic on frozen lawns.
Common Illinois challenges
Severe storms; clay soil in much of state; high deer pressure; emerald ash borer destruction; flooded springs in Mississippi River valley. For region-specific guidance, see our Midwest regional gardening guide.
Where to get Illinois-specific advice
The most reliable source for local growing advice is your county Extension office. University of Illinois Extension has county offices that provide free soil testing, plant disease diagnosis, and growing recommendations specific to your microclimate.
Visit University of Illinois Extension for the office nearest you.
Related tools and guides
- Find your USDA zone by ZIP code
- Look up your average frost dates
- Seasonal care calendar by zone
- Seed starting timeline calculator
- Midwest regional gardening guide