Bethlehem, New Hampshire, sits in USDA hardiness zone 5a — a zone band wide enough that plant choice, not possibility, is the interesting question.
Reliable performers under these conditions include cabbage, cranberry, lavender, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Even in Bethlehem, 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 Bethlehem 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 Bethlehem — soil, climate, flood, and parcel records. How we handle your address.
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Bethlehem — the short answer
Bethlehem, New Hampshire: USDA zone 5a, about 155 days between hard freezes, across 1K acres of town.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 6
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 8
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~155
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 1K 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 5a is Bethlehem's average, not your lot's — a low corner or a tree line moves it. Against Bethlehem's 155-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Bethlehem
Each reading below is measured for Bethlehem itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredBethlehem runs about 155 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
MeasuredBethlehem sits in USDA hardiness zone 5a.
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 Bethlehem is in
Bethlehem sits in the Northeastern Highlands — EPA Level III, inside the wider Northern Forests. That is read at Bethlehem's own centroid rather than borrowed from Grafton County.
What Grows in Bethlehem
Every plant below cleared Bethlehem's own zone 5a and its 155-day season. Each card opens that plant's New Hampshire profile. How we score.
Is it too late to plant in Bethlehem?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Apr 8; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 6 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 8 — long-season crops need about 90 days of runway, quick greens only 30. Even past midsummer there is room for a true fall garden here, and garlic planted near the close carries the momentum into next year.
Documented around Bethlehem
Survey cells within 31 miles of Bethlehem checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 56 miles off. What to watch for.
What's on the federal record near Bethlehem
Closest first, within ~10 miles of Bethlehem. Listing isn't leaking, and distance isn't exposure.
- FORMER SINCLAIR HOTEL PROPERTYUnderground Storage Tanks · 700 ft
- BETHLEHEM CIRCLE KUnderground Storage Tanks · 1100 ft
- WHITE MOUNTAIN TRANSMISSIONUnderground Storage Tanks · 1100 ft
- TOWN OF BETHLEHEM PROPERTY (MAPLEHURST)Underground Storage Tanks · 1800 ft
- BETHLEHEM HIGHWAY GARAGEUnderground Storage Tanks · 2100 ft
- FORMER MAPLEWOOD GARAGEUnderground Storage Tanks · 1.4 mi
- NH-BSW 117Nitrate · 1.5 mi
- DOLLAR GENERAL 18150Brownfields · 1.5 mi
- NH DETOXBrownfields · 1.8 mi
- THE MAPLEWOODUnderground Storage Tanks · 1.8 mi
- NH-BSW 92Nitrate · 2.0 mi
- THE ROCKS ESTATEUnderground Storage Tanks · 2.3 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Bethlehem'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 Bethlehem.
Total Sites
228
within ~10 miles of Bethlehem
Risk Level
Elevated
Highest-severity
11 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Bethlehem
Severity Distribution
within ~10 miles of Bethlehem
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Bethlehem, Nitrate runs higher than the national average — 64 sites within ~10 miles of Bethlehem. That's not a problem with your land — it's information about 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 Bethlehem
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 Bethlehem average
Your land is one point inside Bethlehem
Everything above resolves to Bethlehem as a whole — one PHZM band and one 28°F frost record, read across 1K 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 Bethlehem Average
Bethlehem Average
- ●USDA Zones 5a, averaged across Bethlehem
- ●One soil character for all of Bethlehem
- ●Frost dates read at Bethlehem's scale: May 6 to Oct 8
YOUR Parcel
- ✓Your exact zone, not Bethlehem's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Bethlehem
Pull a site-specific report for your exact address in Bethlehem, New Hampshire — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Bethlehem averages can't show:
We read public map data around Bethlehem — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Bethlehem average
How we know this about Bethlehem
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 Bethlehem’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 Bethlehem
When does frost risk typically end in Bethlehem?
The last hard freeze (28°F) in Bethlehem typically lands around May 6, 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 27.
When is the first frost in Bethlehem?
The first hard freeze (28°F) in Bethlehem typically arrives around Oct 8, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 24, so the watching starts about Sep 8 — about 155 days after the spring freeze cleared.
How long is the growing season in Bethlehem?
Measured between 28°F hard freezes, Bethlehem sees about 155 frost-free days — roughly May 6 through Oct 8, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 27 to Sep 24, about 120 days.
Is the soil safe to grow vegetables in Bethlehem?
The federal record around Bethlehem is a meaningful one — 228 documented sites, mostly Underground Storage Tanks entries (106), the nearest Underground Storage Tanks record about 0.1 miles out — so a soil test before new food beds is a sensible precaution here, not a reason to hold back from growing. Remember that proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what sits where.
How do I protect my plants from frost in Bethlehem?
From about Sep 8 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 8 (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 8. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Bethlehem's scale — its 5a band and its 155-day season. Your yard writes its own version of Bethlehem'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 Bethlehem’s own scale
7 of the readings below were taken at Bethlehem's own scale — its own ~155-day season between 28°F freezes, the 1,046 acres it covers and 228 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Bethlehem's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Bethlehem's own 28°F hard-freeze dates, about May 6 and Oct 8 and the ~155-day span between themNOAA 1991–2020 Climate Normals
- 228 documented contamination sites on the federal record near Bethlehem, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Bethlehem's boundary and the 1,046 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~155-day seasonGrowable Ground crop-matching engine
- The ecoregion at Bethlehem's own centroid, the Northeastern HighlandsUS EPA Level III Ecoregions
- Lanternfly survey cells around Bethlehem checked, none carrying a detectionlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Bethlehem's 1,046 acres read through its county's SSURGO summaryfrom Grafton County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Grafton 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 Grafton County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Bethlehem's 1,046 acreswhy one lot differs from the next →
- Which side of Bethlehem you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,046 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.1 miles 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 Bethlehem-wide figureread your own land →
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