When to plant yardlong bean in Illinois
Illinois spans USDA zones 5a–7a, so the right time to plant yardlong bean shifts by weeks across the state. The window to transplant seedlings outdoors runs from about April 18 in Granite City to May 15 in McHenry — below are local dates for 226 cities, each computed from its own frost dates.
| City | Zone | Last frost | First frost | Transplant out |
|---|---|---|---|---|
| Chicago | 6a | April 10 | November 5 | April 24 – May 1 |
| Aurora | 5b | April 19 | October 23 | May 3 – May 10 |
| Naperville | 5b | April 28 | October 16 | May 12 – May 19 |
| Joliet | 5b | April 19 | October 25 | May 3 – May 10 |
| Rockford | 5b | April 24 | October 17 | May 8 – May 15 |
| Elgin | 5b | April 26 | October 18 | May 10 – May 17 |
| Springfield | 6a | April 15 | October 22 | April 29 – May 6 |
| Peoria | 6a | April 16 | October 23 | April 30 – May 7 |
Yardlong Bean in Illinois: FAQ
When can I plant yardlong bean in Illinois?
Across Illinois, the time to transplant yardlong bean spans roughly April 18 in Granite City to May 15 in McHenry, each following that city's local frost dates.
Does the yardlong bean planting date vary across Illinois?
Yes. Illinois publishes 226 cities with their own frost dates, so the right yardlong bean planting window shifts by weeks between the warmest and coldest parts of the state — use your city's page for the exact dates.
How long does yardlong bean take to grow in Illinois?
Yardlong Bean takes about 70–90 days to reach harvest once planted — check that this fits inside your city's frost-free season on its place page.
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