New London, New Hampshire, sits in USDA hardiness zone 6a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Reliable performers under these conditions include cabbage, hazelnut, lavender, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Even in New London, no two yards are alike.
A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single New London lot. Enter your address and we'll score 1,086 plants against your land's actual soil, sun, and frost.
We read public map data around New London — soil, climate, flood, and parcel records. How we handle your address.
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New London — the short answer
New London, New Hampshire: USDA zone 6a, about 183 days between hard freezes, across 711 acres of town.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 23
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 23
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~183
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 711 acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are this town’s own 28°F normals: light frosts run a few weeks past them, and tender transplants usually wait 2–3 weeks after the last hard freeze.
Hardiness Zone Range
Zone 6a is New London's average, not your lot's — a low corner or a tree line moves it. Against New London's 183-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in New London
Each reading below is measured for New London itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredNew London runs about 183 days between hard freezes — a moderate growing season.
There is room for the full run of cool-season crops plus a warm-season main crop, but the calendar is tight enough that a late spring or early fall frost still decides how much finishes.
Time warm-season transplants to your last hard freeze, and a few weeks of season extension turns a near-miss harvest into a sure one.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredNew London sits in USDA hardiness zone 6a.
The zone sets which perennials, shrubs, and fruit trees live through an average winter here — a plant rated for a colder zone is a safe bet, one rated warmer needs winter protection or gets treated as an annual.
Match perennials and fruit to the zone before you buy, so nothing you plant is a gamble against the cold.
USDA PHZM 2023
The kind of country New London is in
New London sits in the Northeastern Highlands — EPA Level III, inside the wider Northern Forests. That is read at New London's own centroid rather than borrowed from Merrimack County.
What Grows in New London
Every plant below cleared New London's own zone 6a and its 183-day season. Each card opens that plant's New Hampshire profile. How we score.
Is it too late to plant in New London?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Mar 26; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 23 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 23 — long-season crops need about 90 days of runway, quick greens only 30. As the window narrows, the plantings just get faster — fall brassicas, then greens, then garlic to finish.
Documented around New London
Spotted lanternfly documented 20 miles from New London, first recorded 2023. What to watch for.
What's on the federal record near New London
Closest first, within ~10 miles of New London. Listing isn't leaking, and distance isn't exposure.
- COLBY-SAWYER COLLEGE/MAINTENANCE GARAGEUnderground Storage Tanks · 250 ft
- TDS COMMUNICATIONSUnderground Storage Tanks · 850 ft
- NEW LONDON MINI MARTUnderground Storage Tanks · 1300 ft
- COLBY-SAWYER COLLEGEBrownfields · 2000 ft
- FORMER NEW LONDON FUEL ENERGY INCUnderground Storage Tanks · 2600 ft
- HIGHWAY DEPTUnderground Storage Tanks · 0.5 mi
- NEW LONDON CLEANERSBrownfields · 0.6 mi
- NH DESBrownfields · 0.6 mi
- NEW LONDON JIFFY MARTUnderground Storage Tanks · 0.6 mi
- ORANGE PHOTONICS INCBrownfields · 0.7 mi
- JAKES MARKET & DELIUnderground Storage Tanks · 0.8 mi
- NEW LONDON HOSPITALUnderground Storage Tanks · 0.8 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from New London's center, not your beds. Run your own address for what's upwind of you specifically.
Environmental Intelligence
The counts behind that headline — every source type on the record near New London.
Total Sites
193
within ~10 miles of New London
Risk Level
Moderate
Highest-severity
3 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of New London
Severity Distribution
within ~10 miles of New London
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around New London, Nitrate runs higher than the national average — 64 sites within ~10 miles of New London. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in New London
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,086 plant recommendations.
25+ data sources read at your address, not the New London average
Your land is one point inside New London
Everything above resolves to New London as a whole — one PHZM band and one 28°F frost record, read across 711 acres. Your parcel is one point inside that footprint. Slope, tree cover, a low spot that pools cold air, and what is in the soil are all resolved at the address, and none of them are visible at town scale. That is the honest boundary of this page, and the reason the next step is a reading of your own ground rather than a better local average.
Your Lot vs the New London Average
New London Average
- ●USDA Zones 6a, averaged across New London
- ●One soil character for all of New London
- ●Frost dates read at New London's scale: Apr 23 to Oct 23
YOUR Parcel
- ✓Your exact zone, not New London's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in New London
Pull a site-specific report for your exact address in New London, New Hampshire — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that New London averages can't show:
We read public map data around New London — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the New London average
How we know this about New London
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at New London’s own record; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at town grain anywhere on this page — there is no town-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about New London
When does frost risk typically end in New London?
The last hard freeze (28°F) in New London typically lands around Apr 23, per NOAA 1991–2020 climate normals — earlier than the light-frost dates most charts quote. That marks the hard freeze, not the last light frost — lighter frosts keep biting past it, which is why tender transplants here wait until about May 14.
When is the first frost in New London?
The first hard freeze (28°F) in New London typically arrives around Oct 23, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 9, so the watching starts about Sep 23 — about 183 days after the spring freeze cleared.
How long is the growing season in New London?
Measured between 28°F hard freezes, New London sees about 183 frost-free days — roughly Apr 23 through Oct 23, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 14 to Oct 9, about 148 days.
Is the soil safe to grow vegetables in New London?
The federal record around New London shows 193 documented sites, mostly Underground Storage Tanks entries (94), the nearest Underground Storage Tanks record under a tenth of a mile out — a typical footprint for a growing area, and proximity to a documented site is information, not a diagnosis of any one yard. It's worth seeing which recorded sites sit closest to where you grow, and testing the soil before new food beds near any of them.
How do I protect my plants from frost in New London?
From about Sep 23 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Oct 23 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Oct 23. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at New London's scale — its 6a band and its 183-day season. Your yard writes its own version of New London's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at New London’s own scale
7 of the readings below were taken at New London's own scale — its own ~183-day season between 28°F freezes, the 711 acres it covers and 193 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- New London's own USDA hardiness band, zones 6aUSDA PHZM 2023
- New London's own 28°F hard-freeze dates, about Apr 23 and Oct 23 and the ~183-day span between themNOAA 1991–2020 Climate Normals
- 193 documented contamination sites on the federal record near New London, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- New London's boundary and the 711 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~183-day seasonGrowable Ground crop-matching engine
- The ecoregion at New London's own centroid, the Northeastern HighlandsUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of New Londonlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so New London's 711 acres read through its county's SSURGO summaryfrom Merrimack County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Merrimack County
- The growing challenges every New Hampshire grower plans around — written at state scale, so they stay on the state guidefrom New Hampshire
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Merrimack County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among New London's 711 acreswhy one lot differs from the next →
- Which side of New London you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 711 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record under a tenth of a mile out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any New London-wide figureread your own land →
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