Yes — Strong Match
buckwheat (zones 3-10) covers every zone New Hampshire contains (3b-6b), so hardiness is not what limits it anywhere in the state.
Buckwheat in New Hampshire — the short answer
Buckwheat in New Hampshire: hardy in zones 3–10, full sun, against a state median of ~171 frost-free days.
- Plant zones
- 3-10
- Manual horticultural correction (source not retained); NC State Extension and Missouri Botanical Garden, with the remaining rows from other published sources or Growable Ground compilation
- New Hampshire zones
- 3b-6b
- USDA PHZM 2023
- Frost window
- Apr 22 - May 4 – Oct 10 - Oct 21
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 145 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
- Days to maturity
- 45 days
- Growable Ground Plant Database
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — per-field provenance varies and is published with the dataset.
Your yard isn't the whole zone.
Buckwheat is grown as an annual, so your winter zone isn't the deciding factor — your frost-free window is. A typical New Hampshire site runs ~171 frost-free days, but that is a state median, not your yard: slope, trees, and low spots move the last-frost date across a single parcel. Enter your address and we'll score buckwheat against your land's actual frost dates, sun, and soil.
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New Hampshire is not one climate
A single New Hampshire answer averages 10 counties whose growing seasons are 43 days apart — from 145 frost-free days in Coos County to 188 in Rockingham County. Which end of that your land sits nearer changes what buckwheat can finish before the first hard freeze.
The middle half of 10 counties runs 159–183 days, with a median of 169 days — a 43-day span end to end.
Measured across 10 New Hampshire counties. NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze. Quartiles are order statistics — every figure shown is a value a real county recorded, not an interpolation. Your own site sits somewhere inside this range; a parcel report resolves where.
Where in New Hampshire Fits Best
Even within New Hampshire's zones 3b-6b, county microclimates differ enough to change what thrives. These counties carry the closest zone match for buckwheat (USDA PHZM 2023):
Zone Comparison
Buckwheat Needs
- USDA Zones: 3-10
- Frost-Free Days: 55+
- Sun: Full Sun
- Mature size: 2.5 ft tall
- Drought tolerance: Low
New Hampshire Has
- USDA Zones: 3b-6b
- Last Hard Freeze (28°F): Apr 22 - May 4
- First Hard Freeze (28°F): Oct 10 - Oct 21
- Annual Rainfall: 36-50 inches
- Common Soils: Glacial till, Sandy loam, Rocky loam
Plant Zone Range (zones 3-10)
Preferred Soil pH
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS, and university Extension sources — per-field provenance varies and is published with the dataset. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Buckwheat in New Hampshire
The frost window
Across New Hampshire, the last spring hard freeze (28°F) clears between Apr 22 and May 4, and the first fall hard freeze lands between Oct 10 and Oct 21 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 159-day window you can count on — up to 182 days on a mild site in a kind year. That marks the hard freeze, not the last light frost, so tender transplants usually wait another 2-3 weeks.
Frost hardiness
Buckwheat takes cold down to about 28°F before a freeze kills it (FAO ECOCROP), so you can plant on the early side of New Hampshire's window — even a few weeks before the final hard freeze. That is the point where cold damages growing tissue, not a winter-survival floor — an established perennial comes through far colder while dormant, which is what its hardiness zone tells you.
When to start the seed
Buckwheat is direct-sown where it grows rather than started under cover, so there is no seed-tray head start to bank — New Hampshire's dates above are the whole calendar for it. That makes the last-freeze date the binding constraint, and a warmer pocket of your own yard is worth more to this crop than it is to a transplanted one.
Days to maturity vs. the window
At 45 days to maturity (Growable Ground Plant Database), counting from the last hard freeze it ripens with 114 days to spare even in New Hampshire's tightest freeze scenario — room for a later start or a second sowing.
Timing tuned to sub-state frost dates — Coos County, not the statewide average.
Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: Growable Ground Plant Database — frost-free days from FAO ECOCROP, days to harvest from university Extension production guides, and growing-degree-day and chill-hour minimums that are compilation estimates rather than published figures. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.
Growing Season Fit
The zone check says buckwheat survives winter here. Whether the season is long enough — and warm enough — is a different question.
Frost-free days
Buckwheat wants 55+ frost-free days; a typical New Hampshire site sees ~171 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.
Growing degree days
Buckwheat needs ~1100 GDD (base 50°F) to ripen. The state median runs ~1870 GDD (from PRISM 1991-2020 climate normals), so New Hampshire's typical season clears that easily.
GDD and chill-hour figures are computed from PRISM 1991-2020 monthly climate normals; frost-free days from NOAA Regional Climate Centers ACIS, 1991-2020. Each is the state median across its counties (P25/P75 span the within-state spread). Hardiness-zone range is USDA PHZM 2023.
Soil + Drainage Fit
Buckwheat tolerates a wide pH range (pH 4.4-7.5) — 3.1 units, acid ground through alkaline — so soil acidity is rarely what limits it in New Hampshire. A soil test is still worth having, but for what else it tells you about this site, not to clear this plant. It will grow across that whole span, but it does best between pH 5 and 6.5 — worth knowing before you decide whether a New Hampshire soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your New Hampshire site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
SSURGO maps about 8.5% of New Hampshire as poorly or somewhat-poorly drained, and the class flips parcel to parcel. Buckwheat has low drought tolerance, so it is the fast-draining end that will cost you — your soil map unit, not the state average, is the real answer.
Check your parcel → Source: USDA NRCS SSURGO.
Plant pH requirements: FAO ECOCROP and USDA PLANTS, with the remaining rows from other published sources or Growable Ground compilation. Drainage: FAO ECOCROP, with the remaining rows from other published sources or Growable Ground compilation. New Hampshire soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
What Else to Consider for Buckwheat in New Hampshire
Zone compatibility tells you about winter cold survival — but New Hampshire growers also need to think about:
Very short season in the White Mountains (80-100 frost-free days)
Rocky glacial soils throughout the state
Harsh winters with deep snow cover
Growing buckwheat here specifically
Buckwheat wilts without steady moisture and rates to zones 3–10; roughly 15.0% of New Hampshire sits on sandy, excessively-drained ground (SSURGO) that sheds water almost as fast as it falls.
Hold moisture for buckwheat with deep mulch and drip lines, especially on the droughtiest parcels. How to handle it →
What to actually do about these — and the constraints that apply to every New Hampshire grower, not just buckwheat — is covered on the New Hampshire growing guide.
Timing shifts within New Hampshire
New Hampshire isn't one climate. In Coos County, the last hard freeze (28°F) holds until about May 13 — roughly 16 days later than the recorded state median — so plant buckwheat to your county's window, not the statewide date.
Buckwheat needs about 55 days of frost-free season to complete its cycle. Even Coos County — New Hampshire’s shortest season at 145 frost-free days — clears that by 90 days, so season length isn’t the constraint anywhere in New Hampshire. What varies is your own parcel.
County last-freeze dates and frost-free day counts: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F freeze (earlier than the folk 32°F "last frost"). Buckwheat's 55-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.
Pollinator + Wildlife Value
Buckwheat draws honeybees, native bees, and butterflies (high value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, buckwheat can only work that bloom inside New Hampshire's frost window — roughly 171 days, opening after the last 28°F freeze (Apr 22 - May 4) and closing at the first (Oct 10 - Oct 21), per NOAA Regional Climate Centers ACIS, 1991-2020.
New Hampshire Cooperative Extension
For New Hampshire-specific cultivar recommendations, planting calendars, and pest pressure for buckwheat, the canonical source is UNH Cooperative Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Buckwheat native to New Hampshire?
No — the USDA PLANTS Database lists Buckwheat as introduced rather than native in the Lower 48, so it is not part of New Hampshire's native flora. It grows here as a garden plant; pairing it with a few New Hampshire natives keeps local pollinators fed too.
Looking for plants that belong here? The New Hampshire growing guide lists USDA-documented natives for the state.
Native-range data: USDA PLANTS Database state-distribution records, accessed 2026-07-01.
Common Questions About Growing Buckwheat in New Hampshire
When can I plant Buckwheat in New Hampshire?
New Hampshire's last spring hard freeze (28°F) clears between Apr 22 and May 4, and the first fall hard freeze lands between Oct 10 and Oct 21 (NOAA Regional Climate Centers ACIS, 1991-2020). Buckwheat takes cold to about 28°F before a freeze kills it (FAO ECOCROP — the point where cold damages growing tissue, not a winter-survival floor), so plant on the early side of that window — even ahead of the final hard freeze.
Can Buckwheat mature before first frost in New Hampshire?
Yes — Buckwheat matures in 45 days (Growable Ground Plant Database), and New Hampshire's dependable hard-freeze-free window runs 159 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 114 days of margin. Plant once the last hard freeze has passed — two to three weeks later for anything tender — and it ripens ahead of the first fall freeze.
What hardiness zone is Buckwheat grown in across New Hampshire?
New Hampshire spans USDA hardiness zones 3b-6b (USDA ARS PHZM 2023). Buckwheat carries a range of zones 3-10, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical New Hampshire site have?
A typical New Hampshire site sees ~171 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Buckwheat needs 55+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date. In cooler counties like Coos, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is Buckwheat native to New Hampshire?
No — the USDA PLANTS Database lists Buckwheat as introduced rather than native in the Lower 48, so it is not part of New Hampshire's native flora. It grows here as a garden plant; pairing it with a few New Hampshire natives keeps local pollinators fed too.
How should I amend the soil for Buckwheat in New Hampshire?
Buckwheat tolerates pH 4.4-7.5 and well (dry spells) drainage (FAO ECOCROP). That is a 3.1-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a New Hampshire site — amend for drainage and organic matter first.
Will Buckwheat actually grow on my specific land in New Hampshire?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores buckwheat against your address's exact soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.
Check your specific parcel in New Hampshire
State-level data is a sketch. Your Growable Ground report scores buckwheat against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that New Hampshire buckwheat averages can't show:
We read public map data around New Hampshire — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the New Hampshire buckwheat average
Explore More
Growing guides for buckwheat
Explore New Hampshire county by county
New Hampshire carries 10 counties with their own USDA zone — a sample of the growing pages for buckwheat there:
Where else buckwheat grows
Buckwheat's zone band crosses state lines — these are the states closest to New Hampshire in winter climate where it also has a page, plus the far ends of its range. Each one re-answers the question with that state's own record.
More to grow in New Hampshire
New Hampshire has a growing page for 806 plants — a rotating sample of the rest of the shelf.
Analysis by the Growable Ground research team, grounded in USDA PLANTS, USDA NRCS SSURGO, NOAA Climate Normals (1991-2020), and named Cooperative Extension sources. How we know →
Cite this dataset
Kirchick, M. (2026). Growable Ground Plant Database [Data set]. Zenodo. https://doi.org/10.5281/zenodo.21435643
Licensed CC BY-NC 4.0. DOI 10.5281/zenodo.21435643
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