When to plant onion in Kentucky
Kentucky spans USDA zones 6b–7b, so the right time to plant onion shifts by weeks across the state. The window to transplant seedlings outdoors runs from about March 3 in Shively to April 3 in Shelbyville — below are local dates for 46 cities, each computed from its own frost dates.
| City | Zone | Last frost | First frost | Transplant out |
|---|---|---|---|---|
| Louisville/Jefferson County metro government | 7a | April 6 | November 1 | March 9 – March 23 |
| Lexington-Fayette urban county | 7a | April 13 | October 28 | March 16 – March 30 |
| Bowling Green | 7a | April 5 | October 31 | March 8 – March 22 |
| Owensboro | 7a | April 2 | November 1 | March 5 – March 19 |
| Covington | 6b | April 16 | October 25 | March 19 – April 2 |
| Georgetown | 6b | April 18 | October 23 | March 21 – April 4 |
| Richmond | 7a | April 15 | October 22 | March 18 – April 1 |
| Florence | 6b | April 18 | October 25 | March 21 – April 4 |
Onion in Kentucky: FAQ
When can I plant onion in Kentucky?
Across Kentucky, the time to transplant onion spans roughly March 3 in Shively to April 3 in Shelbyville, each following that city's local frost dates.
Does the onion planting date vary across Kentucky?
Yes. Kentucky publishes 46 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 Kentucky?
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.
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