Yes — Strong Match
basil is grown as an annual, so season length decides it here, not a winter zone — and New Hampshire's typical season runs ~171 frost-free days against the ~80 basil needs.
Sow by about Aug 11
Basil is grown as an annual, so what decides it here is season length, not a winter zone. It needs about 80 frost-free days and a typical New Hampshire season runs ~171 frost-free days, leaving 91 days of slack. That is room to sow as late as about Aug 11 and still finish before the usual first freeze (Oct 15).
Want more weeks at either end of that window? How to buy the weeks →
80 frost-free days required against New Hampshire’s ~171-day season. NOAA Regional Climate Centers ACIS 1991-2020 (28°F killing freeze), state median across counties, via stateClimateData.ts.
Basil in New Hampshire — the short answer
Basil in New Hampshire: hardy in zones 10–11, full sun, against a state median of ~171 frost-free days.
- Plant zones
- 10-11
- Not verified — NC State Extension Gardener Plant Toolbox lists zones 10a–10b
- 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
- 65 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.
New Hampshire spans zones 3b-6b, but your yard sits in exactly one — and slope, tree cover, and cold-air pockets nudge it further. Enter your address and we'll score basil against your parcel's actual hardiness, soil, and sun.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
No card required · your parcel report in seconds — read in full free for your first 14 days
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 basil 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.
Zone Comparison
Basil Needs
- USDA Zones: 10-11
- Frost-Free Days: 80+
- Sun: Full Sun
- Mature size: 2 ft tall
- Picking window: ~60 days of harvest
- 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 10-11)
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 Basil 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.
When to start the seed
Those dates are when basil goes out, not when it starts. It is sown under cover about 5 weeks ahead, so counting back from New Hampshire's late-side last freeze of May 4 is what fixes your sowing date — and a yard that clears frost earlier than the state's late date starts earlier still.
Winter standing
New Hampshire runs as cold as USDA zone 3, and no sourced winter-hardiness floor is on record for basil, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether basil is a permanent planting or a replant-every-spring crop for you turns on your own zone within New Hampshire; check its hardiness range against that before treating it as long-lived ground.
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
Frost-free days
Basil wants 80+ 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
Basil 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
Basil tolerates a wide pH range (pH 4.3-8.2) — 3.9 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 6 and 7 — 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. Basil 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.
Before you plant basil for food
Anything you grow to eat takes up what is in the ground it grows in, so what is on record near you is worth knowing before basil goes in. What follows is New Hampshire’s documented federal record at state scale — a screening signal, not a soil test, and not a statement about any one lot.
Safe to Grow Here?
What the federal record shows across New Hampshire — and how to grow with it.
We checked the federal record across New Hampshire — 10,091 documented sites across 8 of the 8 source types we track.
The most significant on record: 82 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
New Hampshire carries one of the heavier federal records we track — and that's not a verdict on your yard. Proximity to a documented site is information, not a diagnosis: nothing here says any particular parcel is affected. It does earn one concrete step — before food beds go in the ground, a professional soil test tells you exactly what you're working with, and raised beds with clean imported soil grow well almost anywhere in the meantime.
Sources Checked
across New Hampshire
Severity Distribution
across New Hampshire
Highest-Severity Sites
Know Before You Grow
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •Near a brownfield, raised beds of imported soil give your food clean ground.
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 8 federal source types.
What Else to Consider for Basil 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 basil here specifically
Basil has low drought tolerance and roots run shallow, so it can't chase deep water; about 15.0% of New Hampshire's soils are excessively drained (SSURGO) and dry out fast between rains.
Mulch basil heavily and set it up with steady drip irrigation on the sandiest ground. How to handle it →
What to actually do about these — and the constraints that apply to every New Hampshire grower, not just basil — 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 basil to your county's window, not the statewide date.
Basil needs about 80 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 65 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"). Basil's 80-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
Basil draws honeybees and native bees (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, basil 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.
Recommended Basil Varieties for New Hampshire
New Hampshire publishes no state variety trial for basil, so we won't invent a "best for New Hampshire" list. Choose types rated to your USDA hardiness zone (3b-6b), and confirm winter survival and drainage against your own parcel.
New Hampshire Cooperative Extension
For New Hampshire-specific cultivar recommendations, planting calendars, and pest pressure for basil, the canonical source is UNH Cooperative Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Basil native to New Hampshire?
No — the USDA PLANTS Database lists Basil 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.
What pests threaten basil in New Hampshire?
Japanese beetle is documented in New Hampshire and will find basil, but it is manageable here. What an experienced grower watches for, and does:
Japanese beetle
Worth watchingThis is on the University of Minnesota's list of Japanese beetle preferred plants — but their read is that fruits, vegetables and herbs tolerate limited leaf feeding, and that in most cases the damage is cosmetic and will not kill the plant.
What to do: Protect it only through the few peak weeks: handpick into soapy water in the cool of morning, harvest regularly through July and August to take the feeding pressure off the edible parts, and keep the plant well watered — a vigorous plant outgrows feeding that looks worse than it is. Do not hang a beetle trap.
Documented range: states listed as Japanese-beetle infested · University of Minnesota Extension, National Plant Board
Only pests whose documented range and host relationship both trace to a primary source appear here — so a quiet section means we have nothing sourced to tell you, not that your garden is pest-free.
Common Questions About Growing Basil in New Hampshire
When can I plant Basil 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). No sourced winter-hardiness floor is on record for Basil, so this page does not state whether it overwinters in New Hampshire and publishes no fall establishment date for it — check its hardiness range against your own zone before treating it as a permanent planting.
What hardiness zone is Basil grown in across New Hampshire?
New Hampshire spans USDA hardiness zones 3b-6b (USDA ARS PHZM 2023). Basil carries a range of zones 10-11, 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). Basil needs 80+ 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 Basil native to New Hampshire?
No — the USDA PLANTS Database lists Basil 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 Basil in New Hampshire?
Basil tolerates pH 4.3-8.2 and well (dry spells) drainage (FAO ECOCROP). That is a 3.9-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 Basil actually grow on my specific land in New Hampshire?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores basil 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 basil against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that New Hampshire basil 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 basil average
Explore More
Growing guides for basil
Explore New Hampshire county by county
New Hampshire carries 10 counties with their own USDA zone — a sample of the growing pages for basil there:
Where else basil grows
Basil'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 807 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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