When to plant watercress in Idaho
Idaho spans USDA zones 5a–7a, so the right time to plant watercress shifts by weeks across the state. The window to sow seed directly 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 | Direct sow |
|---|---|---|---|---|
| Boise City | 7a | April 24 | October 21 | April 10 – May 8 |
| Meridian | 7a | April 24 | October 21 | April 10 – May 8 |
| Nampa | 7a | April 29 | October 13 | April 15 – May 13 |
| Idaho Falls | 5b | May 9 | October 1 | April 25 – May 23 |
| Caldwell | 7a | April 29 | October 13 | April 15 – May 13 |
| Pocatello | 6a | May 2 | October 11 | April 18 – May 16 |
| Coeur d'Alene | 6b | April 22 | October 18 | April 8 – May 6 |
| Twin Falls | 7a | April 30 | October 9 | April 16 – May 14 |
Watercress in Idaho: FAQ
When can I plant watercress in Idaho?
Across Idaho, the time to direct-sow watercress spans roughly March 23 in Lewiston to May 3 in Garden City, each following that city's local frost dates.
Does the watercress planting date vary across Idaho?
Yes. Idaho publishes 25 cities with their own frost dates, so the right watercress 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 watercress take to grow in Idaho?
Watercress takes about 45–60 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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