Hillsborough, New Hampshire, sits in USDA hardiness zone 5b — 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 Hillsborough, 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 Hillsborough 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 Hillsborough — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Hillsborough — the short answer
Hillsborough, New Hampshire: USDA zone 5b, about 172 days between hard freezes, across 1K acres of town.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 26
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 15
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~172
- 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 5b is Hillsborough's average, not your lot's — a low corner or a tree line moves it. Against Hillsborough's 172-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Hillsborough
Each reading below is measured for Hillsborough itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredHillsborough runs about 172 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
MeasuredHillsborough sits in USDA hardiness zone 5b.
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 Hillsborough is in
Hillsborough sits in the Northeastern Highlands — EPA Level III, inside the wider Northern Forests. That is read at Hillsborough's own centroid rather than borrowed from Hillsborough County.
What Grows in Hillsborough
Every plant below cleared Hillsborough's own zone 5b and its 172-day season. Each card opens that plant's New Hampshire profile. How we score.
Is it too late to plant in Hillsborough?
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 Mar 29; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 26 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 15 — 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 Hillsborough
Spotted lanternfly documented 30 miles from Hillsborough, first recorded 2021. What to watch for.
What's on the federal record near Hillsborough
Closest first, within ~10 miles of Hillsborough. Listing isn't leaking, and distance isn't exposure.
- CONTOOCOOK VALLEY TELEPHONEUnderground Storage Tanks · 350 ft
- J B VAILLANCOURT OFFICEUnderground Storage Tanks · 700 ft
- MR MIKES HILLSBORO FMR HILLSBORO SUNOCOUnderground Storage Tanks · 750 ft
- NAJIBS PIZZAUnderground Storage Tanks · 800 ft
- NEW ENGLAND KUSTOM & COLLISIONBrownfields · 850 ft
- FORMER GABLES REALTYUnderground Storage Tanks · 1200 ft
- WOODS WOOLEN MILLSuperfund · 1400 ft
- CUMBERLAND FARMS 2843Underground Storage Tanks · 1500 ft
- HILLSBORO-DEERING MIDDLEBrownfields · 1600 ft
- HILLSBORO DEERING HIGH SCHOOLBrownfields · 2200 ft
- NORTON CO.Underground Storage Tanks · 0.5 mi
- NORTON COToxics Release Inventory · 0.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Hillsborough'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 Hillsborough.
Total Sites
173
within ~10 miles of Hillsborough
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Hillsborough
Severity Distribution
within ~10 miles of Hillsborough
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Hillsborough, Nitrate runs higher than the national average — 60 sites within ~10 miles of Hillsborough. 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 Hillsborough
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 Hillsborough average
Your land is one point inside Hillsborough
Everything above resolves to Hillsborough 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 Hillsborough Average
Hillsborough Average
- ●USDA Zones 5b, averaged across Hillsborough
- ●One soil character for all of Hillsborough
- ●Frost dates read at Hillsborough's scale: Apr 26 to Oct 15
YOUR Parcel
- ✓Your exact zone, not Hillsborough's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Hillsborough
Pull a site-specific report for your exact address in Hillsborough, New Hampshire — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Hillsborough averages can't show:
We read public map data around Hillsborough — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Hillsborough average
How we know this about Hillsborough
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 Hillsborough’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 Hillsborough
When does frost risk typically end in Hillsborough?
The last hard freeze (28°F) in Hillsborough typically lands around Apr 26, 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 17.
When is the first frost in Hillsborough?
The first hard freeze (28°F) in Hillsborough typically arrives around Oct 15, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 1, so the watching starts about Sep 15 — about 172 days after the spring freeze cleared.
How long is the growing season in Hillsborough?
Measured between 28°F hard freezes, Hillsborough sees about 172 frost-free days — roughly Apr 26 through Oct 15, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 17 to Oct 1, about 137 days.
Is the soil safe to grow vegetables in Hillsborough?
The federal record around Hillsborough is a meaningful one — 173 documented sites, mostly Underground Storage Tanks entries (77), the nearest Underground Storage Tanks record under a tenth of a mile 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 Hillsborough?
From about Sep 15 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 15 (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 15. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Hillsborough's scale — its 5b band and its 172-day season. Your yard writes its own version of Hillsborough'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 Hillsborough’s own scale
7 of the readings below were taken at Hillsborough's own scale — its own ~172-day season between 28°F freezes, the 1,245 acres it covers and 173 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Hillsborough's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Hillsborough's own 28°F hard-freeze dates, about Apr 26 and Oct 15 and the ~172-day span between themNOAA 1991–2020 Climate Normals
- 173 documented contamination sites on the federal record near Hillsborough, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Hillsborough's boundary and the 1,245 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~172-day seasonGrowable Ground crop-matching engine
- The ecoregion at Hillsborough's own centroid, the Northeastern HighlandsUS EPA Level III Ecoregions
- A documented spotted-lanternfly record within reach of Hillsboroughlydemapr (De Bona & Helmus), 10 km survey lattice
Inherited from a wider read
- Soil character — no town-scale survey exists, so Hillsborough's 1,245 acres read through its county's SSURGO summaryfrom Hillsborough County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Hillsborough 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 Hillsborough County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Hillsborough's 1,245 acreswhy one lot differs from the next →
- Which side of Hillsborough you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,245 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 Hillsborough-wide figureread your own land →
More in New Hampshire
Growing region
Nearby growing guides