Illinois · zones 5b–6b
When to plant green beans in Illinois.
Sow between Apr 20 to Jun 10 in a typical year, keyed to Illinois's median last frost around Apr 20. A second, fall sowing fits Jul 4 to Aug 6. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Green Beans dates for a typical Illinois season.
Direct sow
Apr 20 to Jun 10
Keyed to the ~Apr 20 last frost. Sow 1" deep, 3" apart.
Fall round
Jul 4 to Aug 6
Counted back from the ~Oct 18 first frost.
Harvest
~55 days later
~0.75 lb per plant over ~3 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 green beans here.
A middle-length season, about 181 frost-free days, means bush bean overlaps mexican bean beetle for a stretch each summer. Check plants every week or two and treat early.
Coppery ladybug-like beetles; leaves skeletonized to lace.
Organic fix: Handpick adults and yellow egg clusters; neem.
Orange or white spots on leaves late in the season.
Organic fix: Water at the base, space plants, spray neem.
Anthracnose
Sunken dark-red cankers on the pods, and leaf veins turning brick-red to black underneath.
Organic fix: Start with certified seed, water at the base, and stay out of the patch while the leaves are wet.
Your season math: Illinois gives green beans about 181 frost-free days, and it needs roughly 55 days to a first harvest. That fits about 13 re-sown rounds across the season, so you can keep it coming instead of picking once.
Planting green beans in Illinois: questions
When should I plant green beans in Illinois?+
In a typical Illinois year, sow green beans between Apr 20 to Jun 10, keyed to the state's median last frost around Apr 20. There's also a fall window: Jul 4 to Aug 6. 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 green beans 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.