Illinois · zones 5b–6b
When to plant carrots in Illinois.
Sow between Mar 13 to Apr 15 in a typical year, keyed to Illinois's median last frost around Apr 20. A second, fall sowing fits Jul 23 to Aug 18. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Carrots dates for a typical Illinois season.
Direct sow
Mar 13 to Apr 15
Keyed to the ~Apr 20 last frost. Sow 0.25" deep, 2" apart.
Fall round
Jul 23 to Aug 18
Counted back from the ~Oct 18 first frost.
Harvest
~68 days later
~0.2 lb per plant over ~2 weeks.
Illinois spans more than one climate: Zone 6 is the most common zone, but the state runs 5b to 6b. That's why the planner works from your ZIP code's frost dates, not your zone: mountain and coastal gardens in the same state can be three weeks apart.
In Illinois: watch for
The pests that find carrots here.
A middle-length season, about 181 frost-free days, means carrot overlaps carrot rust fly for a stretch each summer. Check plants every week or two and treat early.
Rusty tunnels in the roots and stunted tops.
Organic fix: Cover the row; rotate away from last year's carrots.
Big green-and-black striped caterpillars on the foliage.
Organic fix: Handpick (or leave for swallowtails); Bt if heavy.
Brown spots ringed in yellow on the oldest leaves first, darkening until the tops look scorched.
Organic fix: Water at the base rather than overhead, turn under old carrot tops, and leave 2 years between carrot crops.
Your season math: Illinois gives carrots about 181 frost-free days, and it needs roughly 68 days to a first harvest. That fits about 6 re-sown rounds across the season, so you can keep it coming instead of picking once.
Planting carrots in Illinois: questions
When should I plant carrots in Illinois?+
In a typical Illinois year, sow carrots between Mar 13 to Apr 15, keyed to the state's median last frost around Apr 20. There's also a fall window: Jul 23 to Aug 18. Your exact dates shift with your ZIP code and microclimate.
What USDA zone is Illinois?+
Illinois spans zones 5b–6b, mostly zone 6. But frost dates, not zones, set planting time. The free planner uses your ZIP code's actual frost dates.
How many carrots plants do I need?+
Depends who you're feeding. The crop page has exact counts per household size, or the free planner does the math for your family in about 60 seconds.