When to plant watercress in New Hampshire
New Hampshire spans USDA zones 5a–6a, so the right time to plant watercress shifts by weeks across the state. The window to sow seed directly outdoors runs from about April 15 in Nashua to April 30 in Keene — below are local dates for 15 cities, each computed from its own frost dates.
| City | Zone | Last frost | First frost | Direct sow |
|---|---|---|---|---|
| Manchester | 6a | April 30 | October 11 | April 16 – May 14 |
| Nashua | 6a | April 29 | October 8 | April 15 – May 13 |
| Concord | 5b | May 8 | October 3 | April 24 – May 22 |
| Dover | 6a | May 3 | October 10 | April 19 – May 17 |
| Rochester | 6a | April 30 | October 9 | April 16 – May 14 |
| Keene | 5b | May 14 | October 1 | April 30 – May 28 |
| Portsmouth | 6a | May 4 | October 8 | April 20 – May 18 |
| Derry | 6a | April 30 | October 11 | April 16 – May 14 |
Watercress in New Hampshire: FAQ
When can I plant watercress in New Hampshire?
Across New Hampshire, the time to direct-sow watercress spans roughly April 15 in Nashua to April 30 in Keene, each following that city's local frost dates.
Does the watercress planting date vary across New Hampshire?
Yes. New Hampshire publishes 15 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 New Hampshire?
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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