What Planting Zones Are in New Hampshire?
New Hampshire spans USDA hardiness zones 4a to 6b, where the average coldest winter night ranges from −30 °F to 0 °F (−34.4 °C to −17.8 °C). Zone 6a covers the most ZIP codes, 43%, and zones 5a to 6a together cover 94% of the state.
- Zone 4a2% · 5 ZIPs
- Zone 4b4% · 10 ZIPs
- Zone 5a21% · 59 ZIPs
- Zone 5b30% · 85 ZIPs
- Zone 6a43% · 119 ZIPs
- Zone 6b<1% · 2 ZIPs
Bars show each zone's share of the 280 New Hampshire ZIP codes in the official 2023 USDA ZIP code table; select a zone for its temperatures and hardy plants.
What Hardiness Zone Are New Hampshire Cities In?
Manchester is in zone 6a, Nashua is in zone 6a, Concord is in zone 5b and Dover is in zone 6a. The table lists the zone, winter low and average frost dates for 11 New Hampshire cities, using the ZIP code nearest each city center.
| City | ZIP | Zone | Winter low | Last frost | First frost |
|---|---|---|---|---|---|
| Manchester | 03101 | 6a | −10 °F to −5 °F | Apr 30 | Oct 11 |
| Nashua | 03060 | 6a | −10 °F to −5 °F | Apr 29 | Oct 8 |
| Concord | 03301 | 5b | −15 °F to −10 °F | May 8 | Oct 3 |
| Dover | 03820 | 6a | −10 °F to −5 °F | May 3 | Oct 10 |
| Rochester | 03867 | 6a | −10 °F to −5 °F | Apr 30 | Oct 9 |
| Keene | 03431 | 5b | −15 °F to −10 °F | May 14 | Oct 1 |
| Portsmouth | 03801 | 6a | −10 °F to −5 °F | May 4 | Oct 8 |
| Laconia | 03246 | 5b | −15 °F to −10 °F | Apr 30 | Oct 18 |
| Lebanon | 03766 | 5a | −20 °F to −15 °F | May 9 | Oct 6 |
| Claremont | 03743 | 5b | −15 °F to −10 °F | May 14 | Oct 1 |
| Berlin | 03570 | 4b | −25 °F to −20 °F | May 14 | Sep 30 |
Zone: 2023 USDA ZIP code table for the ZIP code nearest each city's Census center point. Frost dates: 50% (median) dates from the nearest NOAA station, 1991–2020 normals. Cities: the largest New Hampshire places by 2024 Census population estimates, spread across the state, plus the largest place in each common zone. Large cities can span two half zones.
Which Parts of New Hampshire Are in Each Zone?
Zone 4b, the coldest New Hampshire zone with towns, covers 4% of ZIP codes around Berlin. Zone 6a, the warmest with towns, covers 43% around Manchester, Nashua and Dover. The table lists the largest places in every zone.
| Zone | Avg. coldest night | Share of ZIPs | Largest places in this zone |
|---|---|---|---|
| Zone 4a | −30 °F to −25 °F | 2% (5) | Rural ZIP codes only |
| Zone 4b | −25 °F to −20 °F | 4% (10) | Berlin |
| Zone 5a | −20 °F to −15 °F | 21% (59) | Lebanon |
| Zone 5b | −15 °F to −10 °F | 30% (85) | Concord, Keene, Laconia, Claremont |
| Zone 6a | −10 °F to −5 °F | 43% (119) | Manchester, Nashua, Dover, Rochester |
| Zone 6b | −5 °F to 0 °F | <1% (2) | Rural ZIP codes only |
Places: incorporated places with 1,000+ residents, assigned the zone of the ZIP code nearest their Census center point.
What Do the Hardiness Zones Mean for New Hampshire Gardeners?
A New Hampshire gardener in zone 6b sees winter lows about 25 °F milder than one in zone 4a, so a shrub or perennial that thrives in one part of the state can die in another. Choose plants rated to your own ZIP code's zone or colder.
Hardiness zones follow latitude, elevation and large bodies of water rather than state lines. Higher ground and inland valleys that trap cold air usually sit in colder half zones, while cities, coasts and large lakes moderate winter lows. Within New Hampshire, a plant labelled “zones 5–6” survives winter in at least 94% of ZIP codes, but plants at the edge of their range benefit from mulch and a sheltered spot. Enter a ZIP code in the USDA hardiness zone finder by ZIP code to check your exact half zone before buying perennials.
A zone describes winter cold only. Summer heat, humidity, rainfall and soil decide whether a cold-hardy plant thrives, and planting dates for vegetables follow frost dates, not zones: two New Hampshire towns in the same zone can have last frosts weeks apart.
What Plants Grow Well Across New Hampshire?
199 plants in PlantoScan's catalogue are hardy in every zone from 5a to 6a, the zones that cover 94% of New Hampshire ZIP codes. Popular examples include hydrangea, peony and daisy.
Hydrangea
Hydrangea macrophylla
Zone 5 – 9
AI generated
Peony
Paeonia lactiflora
Zone 3 – 8
AI generated
- DaisyBellis perennisPlantoScan
Daisy
Bellis perennis
Zone 4a – 8b
Chrysanthemum
Chrysanthemum morifolium
Zone 5a – 9b
PlantoscanAI generated
Poppy
Papaver somniferum
Zone 3a – 9b
AI generated
Carnation
Dianthus caryophyllus
Zone 5a – 9b
AI generated
Daffodil
Narcissus poeticus
Zone 3 – 8
AI generated
Arugula
Eruca sativa
Zone 5a – 10b
AI generated
Alfalfa
Medicago sativa
Zone 3a – 10a
AI generated
Hardiness ranges come from PlantoScan's plant database; gardeners in New Hampshire's colder or warmer edge zones should check each plant's full range.
When Is the Last Frost in New Hampshire?
Across most New Hampshire ZIP codes, the average last spring frost falls between April 30 and May 19, from April 29 in Nashua to May 14 in Berlin. Tender vegetables such as tomatoes go out 1 to 2 weeks after the local date.
The last and first frost dates for New Hampshire cities include the safer 90% planting date, the fall frost date, growing season length and a tomato planting table for each city.
Frequently Asked Questions
- What planting zone is New Hampshire?
- New Hampshire spans USDA hardiness zones 4a to 6b on the 2023 USDA Plant Hardiness Zone Map. Zone 6a is the most common, covering 43% of the state's 280 ZIP codes, and zones 5a to 6a together cover 94%.
- What hardiness zone is Manchester, New Hampshire?
- Manchester is in USDA hardiness zone 6a (ZIP 03101), where the average coldest winter night reaches −10 °F to −5 °F. Its average last spring frost is April 30 and its first fall frost October 11.
- What hardiness zone is Nashua, New Hampshire?
- Nashua is in USDA hardiness zone 6a (ZIP 03060), where the average coldest winter night reaches −10 °F to −5 °F. Its average last spring frost is April 29 and its first fall frost October 8.
- What hardiness zone is Concord, New Hampshire?
- Concord is in USDA hardiness zone 5b (ZIP 03301), where the average coldest winter night reaches −15 °F to −10 °F. Its average last spring frost is May 8 and its first fall frost October 3.
- What is the coldest hardiness zone in New Hampshire?
- Zone 4a (−30 °F to −25 °F) is the coldest zone in New Hampshire, found in 5 ZIP codes. The warmest is zone 6b (−5 °F to 0 °F).
Zones: 2023 USDA Plant Hardiness Zone Map ZIP code table, USDA Agricultural Research Service and the PRISM Climate Group, Oregon State University, used without changes. Frost dates: NOAA National Centers for Environmental Information, 1991–2020 U.S. Climate Normals. City locations and populations: U.S. Census Bureau Gazetteer files and Vintage 2024 population estimates. PlantoScan is not affiliated with or endorsed by these agencies.