When to plant sweet corn in New Hampshire
New Hampshire spans USDA zones 5a–6a, so the right time to plant sweet corn shifts by weeks across the state. The window to sow seed directly outdoors runs from about April 29 in Nashua to May 14 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 30 – May 14 |
| Nashua | 6a | April 29 | October 8 | April 29 – May 13 |
| Concord | 5b | May 8 | October 3 | May 8 – May 22 |
| Dover | 6a | May 3 | October 10 | May 3 – May 17 |
| Rochester | 6a | April 30 | October 9 | April 30 – May 14 |
| Keene | 5b | May 14 | October 1 | May 14 – May 28 |
| Portsmouth | 6a | May 4 | October 8 | May 4 – May 18 |
| Derry | 6a | April 30 | October 11 | April 30 – May 14 |
Sweet Corn in New Hampshire: FAQ
When can I plant sweet corn in New Hampshire?
Across New Hampshire, the time to direct-sow sweet corn spans roughly April 29 in Nashua to May 14 in Keene, each following that city's local frost dates.
Does the sweet corn planting date vary across New Hampshire?
Yes. New Hampshire publishes 15 cities with their own frost dates, so the right sweet corn 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 corn take to grow in New Hampshire?
Sweet Corn takes about 60–90 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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