When to plant onion in Kansas
Kansas spans USDA zones 6a–7a, so the right time to plant onion shifts by weeks across the state. The window to transplant seedlings outdoors runs from about March 7 in Kansas City to March 31 in Garden City — below are local dates for 35 cities, each computed from its own frost dates.
| City | Zone | Last frost | First frost | Transplant out |
|---|---|---|---|---|
| Wichita | 7a | April 11 | October 29 | March 14 – March 28 |
| Overland Park | 6b | April 10 | October 29 | March 13 – March 27 |
| Kansas City | 6b | April 4 | November 2 | March 7 – March 21 |
| Olathe | 6b | April 10 | October 29 | March 13 – March 27 |
| Topeka | 6b | April 16 | October 22 | March 19 – April 2 |
| Lawrence | 6b | April 12 | October 28 | March 15 – March 29 |
| Shawnee | 6b | April 16 | October 22 | March 19 – April 2 |
| Lenexa | 6b | April 10 | October 29 | March 13 – March 27 |
Onion in Kansas: FAQ
When can I plant onion in Kansas?
Across Kansas, the time to transplant onion spans roughly March 7 in Kansas City to March 31 in Garden City, each following that city's local frost dates.
Does the onion planting date vary across Kansas?
Yes. Kansas publishes 35 cities with their own frost dates, so the right onion 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 onion take to grow in Kansas?
Onion takes about 90–110 days to reach harvest once planted — check that this fits inside your city's frost-free season on its place page.
Never miss a window in your area
An email when it’s time to start seeds, transplant, and sow — timed to your frost dates. Double opt-in, one-click unsubscribe, no spam.