New Hampshire Planting Guide & Growing Season
New Hampshire is in USDA hardiness zone 4a-6a with a growing season of 140 days. The average last spring frost is May 10 and the average first fall frost is Sep 25.
Growing Conditions in New Hampshire
How New Hampshire Compares
Compare New Hampshire's growing conditions with states that have similar climates.
| State | USDA Zone | Last Frost | First Frost | Season (days) |
|---|---|---|---|---|
| New Hampshire (NH) | 4a-6a | May 10 | Sep 25 | 140 |
| Alabama (AL) | 7a-8b | Mar 15 | Nov 5 | 235 |
| Alaska (AK) | 1a-7b | May 30 | Sep 5 | 100 |
| Arizona (AZ) | 4b-10b | Mar 1 | Nov 15 | 260 |
| Arkansas (AR) | 6b-8a | Apr 1 | Oct 25 | 210 |
| California (CA) | 4b-11a | Feb 15 | Nov 30 | 290 |
Frequently Asked Questions About Gardening in New Hampshire
When should I start seeds indoors in New Hampshire?
In New Hampshire, the average last frost date is May 10. Start most seeds indoors 6-8 weeks before this date. The USDA hardiness zone for New Hampshire is 4a-6a, with a growing season of approximately 140 days.
What USDA hardiness zone is New Hampshire?
New Hampshire falls in USDA hardiness zones 4a-6a. This affects which perennial plants will survive winter and influences optimal planting times.
When is the first frost in New Hampshire?
The average first frost date in New Hampshire is Sep 25. Plan to harvest cold-sensitive crops before this date or protect them with row covers.
How long is the growing season in New Hampshire?
New Hampshire has an average growing season of 140 days, from the last frost (May 10) to first frost (Sep 25). This shorter season requires starting many crops indoors and choosing quick-maturing varieties.
Plan Your Garden
Use our seed starting calculator to get personalized planting dates, or browse all states.