When to plant sweet potato in New Hampshire
New Hampshire spans USDA zones 5a–6a, so the right time to plant sweet potato shifts by weeks across the state. The window to transplant seedlings outdoors runs from about May 20 in Nashua to June 4 in Keene — below are local dates for 15 cities, each computed from its own frost dates.
| City | Zone | Last frost | First frost | Transplant out |
|---|---|---|---|---|
| Manchester | 6a | April 30 | October 11 | May 21 – June 4 |
| Nashua | 6a | April 29 | October 8 | May 20 – June 3 |
| Concord | 5b | May 8 | October 3 | May 29 – June 12 |
| Dover | 6a | May 3 | October 10 | May 24 – June 7 |
| Rochester | 6a | April 30 | October 9 | May 21 – June 4 |
| Keene | 5b | May 14 | October 1 | June 4 – June 18 |
| Portsmouth | 6a | May 4 | October 8 | May 25 – June 8 |
| Derry | 6a | April 30 | October 11 | May 21 – June 4 |
Sweet Potato in New Hampshire: FAQ
When can I plant sweet potato in New Hampshire?
Across New Hampshire, the time to transplant sweet potato spans roughly May 20 in Nashua to June 4 in Keene, each following that city's local frost dates.
Does the sweet potato planting date vary across New Hampshire?
Yes. New Hampshire publishes 15 cities with their own frost dates, so the right sweet potato 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 sweet potato take to grow in New Hampshire?
Sweet Potato takes about 90–120 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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