When to plant fennel (bulb) in Idaho
Idaho spans USDA zones 5a–7a, so the right time to plant fennel (bulb) shifts by weeks across the state. The window to transplant seedlings outdoors runs from about March 23 in Lewiston to May 3 in Garden City — below are local dates for 25 cities, each computed from its own frost dates.
| City | Zone | Last frost | First frost | Transplant out |
|---|---|---|---|---|
| Boise City | 7a | April 24 | October 21 | April 10 – April 24 |
| Meridian | 7a | April 24 | October 21 | April 10 – April 24 |
| Nampa | 7a | April 29 | October 13 | April 15 – April 29 |
| Idaho Falls | 5b | May 9 | October 1 | April 25 – May 9 |
| Caldwell | 7a | April 29 | October 13 | April 15 – April 29 |
| Pocatello | 6a | May 2 | October 11 | April 18 – May 2 |
| Coeur d'Alene | 6b | April 22 | October 18 | April 8 – April 22 |
| Twin Falls | 7a | April 30 | October 9 | April 16 – April 30 |
Fennel (Bulb) in Idaho: FAQ
When can I plant fennel (bulb) in Idaho?
Across Idaho, the time to transplant fennel (bulb) spans roughly March 23 in Lewiston to May 3 in Garden City, each following that city's local frost dates.
Does the fennel (bulb) planting date vary across Idaho?
Yes. Idaho publishes 25 cities with their own frost dates, so the right fennel (bulb) 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 fennel (bulb) take to grow in Idaho?
Fennel (Bulb) takes about 65–90 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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