When to plant in New Hampshire
New Hampshire spans USDA hardiness zones 3b-6a. Average last spring frost: mid May. Average first fall frost: late September. This calendar is anchored to UNH Cooperative Extension's recommendations, with timing adjusted for the dominant climate zone of the state.
New Hampshire at a glance
| USDA hardiness zones | 3b-6a |
| Region | Northeast |
| Average last spring frost | mid May |
| Average first fall frost | late September |
| Primary Extension service | UNH Cooperative Extension |
What grows particularly well in New Hampshire
These are the crops, ornamentals, and trees UNH Cooperative Extension highlights as well-suited to New Hampshire's climate:
- apple
- blueberry
- peony
- lilac
- rhododendron
- wildflower mixes
New Hampshire planting calendar
Dates are approximate and based on the dominant USDA zone for the state. For zone-specific timing, use the zone finder by ZIP code and frost date lookup tools.
Spring planting (after last frost: mid May)
Cool-season vegetables (start 2-6 weeks before last frost outdoors): lettuce, spinach, peas, radishes, carrots, beets, kale, broccoli transplants, cabbage transplants.
Warm-season vegetables (after last frost, soil 60F+): tomato transplants, pepper transplants, beans (direct sow), cucumbers, squash, melons. See the seed starting timeline tool for indoor start dates.
Annual flowers (after last frost): zinnia, marigold, cosmos, sunflower, nasturtium.
Perennials, shrubs, trees: Plant in spring after soil thaws but before summer heat. Best window in New Hampshire: 4-6 weeks after last frost.
Summer (June - August)
Maintenance season for most New Hampshire gardens. Mulch heavily, water deeply (1 inch per week), pinch back mums for fall bloom, hand-pull weeds, harvest summer vegetables. Plant fall vegetable starts indoors by mid-July.
Fall planting (before first frost: late September)
Cool-season vegetables (6-8 weeks before first frost): lettuce, spinach, radish, kale, broccoli, cabbage transplants. Per Penn State Extension, fall vegetable production can equal or exceed spring production with proper timing.
Spring-flowering bulbs: tulip, daffodil, allium, crocus, hyacinth. Plant 4-6 weeks before ground freezes. In New Hampshire: typically October-November.
Perennials, shrubs, trees: Fall is the best planting season for woody plants in most of New Hampshire - cooler temperatures + autumn rains reduce transplant stress. Plant 6+ weeks before first hard freeze.
Garlic: Plant cloves in October-November. Harvest the following July.
Winter (December - February)
Most of New Hampshire is in dormancy. Tasks: order seeds, plan next year, dormant prune fruit trees (February), order bare-root plants for spring delivery. Avoid foot traffic on frozen lawns.
Common New Hampshire challenges
Acidic glacial soil; severe winters; short growing season at altitude; high deer pressure; tick-borne disease; emerald ash borer. For region-specific guidance, see our Northeast regional gardening guide.
Where to get New Hampshire-specific advice
The most reliable source for local growing advice is your county Extension office. UNH Cooperative Extension has county offices that provide free soil testing, plant disease diagnosis, and growing recommendations specific to your microclimate.
Visit UNH Cooperative Extension for the office nearest you.
Related tools and guides
- Find your USDA zone by ZIP code
- Look up your average frost dates
- Seasonal care calendar by zone
- Seed starting timeline calculator
- Northeast regional gardening guide