Colebrook, New Hampshire, sits in USDA hardiness zones 4a-5b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Crops well matched to these conditions include apple, sugar maple, blueberry, and potato — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Even in Colebrook, 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 Colebrook lot. Enter your address and we'll score 1,112 plants against your land's actual soil, sun, and frost.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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Quick Facts
USDA Zones
4a-5b
Last Hard Freeze (28°F)
Apr 27
Town normal — light frosts run a few weeks later
First Hard Freeze (28°F)
Oct 25
Town normal — light frosts arrive a few weeks earlier
Town Area
2K acres
Hardiness Zone Range
Zone maps are averages across Colebrook. Your yard's slope, trees, and frost pockets shift what actually grows — see your land's exact reading.
Soil varies lot by lot — soil types explained.
What Grows in Colebrook
Plants matched to Colebrook's USDA zones 4a-5b — each links to its full growing profile.
Is it too late to plant in Colebrook?
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 30; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 27 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 25 — 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.
Growing Challenges in New Hampshire
What an experienced grower plans around here — each one has a move.
Very short season in the White Mountains (80-100 frost-free days)
In the mountains, fast varieties plus a cold frame or hoop house turn 90 days into a working season.
Rocky glacial soils throughout the state
Build up rather than dig out — a raised bed over cleared ground beats fighting granite for every planting hole.
Harsh winters with deep snow cover
Deep snow is a blanket, not a threat — plant to your true zone and the cover protects what the cold would test.
For cultivar selection, pest pressure, and planting-time guidance specific to New Hampshire, the UNH Cooperative Extension is the authoritative local source.
Environmental Intelligence
Understanding what's nearby helps you make informed decisions about where and how to grow.
Total Sites
102
within ~10 miles of Colebrook
Risk Level
Moderate
Highest-severity
2 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Colebrook
Severity Distribution
within ~10 miles of Colebrook
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Colebrook, Nitrate runs higher than the national average — 32 sites nearby. 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 Colebrook
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,112 plant recommendations.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
Your Specific Parcel Matters
Colebrook Average
- ●USDA Zones 4a-5b
- ●Generic soil type for the area
- ●State-average frost dates
YOUR Parcel
- ✓Your exact hardiness zone
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Colebrook
Pull a site-specific report for your exact address in Colebrook, New Hampshire — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
Key Growing Facts for Colebrook, New Hampshire
- USDA Hardiness Zones: 4a-5b (USDA PHZM 2023)
- Last Hard Freeze (28°F): Apr 27 (town normal, NOAA 1991–2020 Climate Normals — light frosts can follow for a few weeks)
- First Hard Freeze (28°F): Oct 25 (town normal, NOAA 1991–2020 Climate Normals — light frosts can arrive a few weeks earlier)
- Days Between Hard Freezes: ~181 (town normal, NOAA 1991–2020 Climate Normals)
- Land Area: 2K acres (US Census TIGER 2025)
Zone data: USDA ARS Plant Hardiness Zone Map 2023. Climate data: NOAA NCEI. Boundaries: US Census TIGER/Line 2025.
Frequently Asked Questions
What hardiness zone is Colebrook, New Hampshire?
Colebrook sits in USDA hardiness zones 4a-5b, per the USDA Plant Hardiness Zone Map 2023. Zones reflect average annual extreme minimum temperatures from 1991–2020 weather data.
Is it too late to plant in Colebrook?
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 30; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 27 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 25 — 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.
When does frost risk typically end in Colebrook?
The last hard freeze (28°F) in Colebrook typically lands around Apr 27, per NOAA 1991–2020 climate normals — an earlier marker than the light-frost dates many planting charts quote. That marks the hard freeze, not the last light frost — light frosts can still bite for a few more weeks, so tender transplants usually wait another 2–3 weeks.
When is the first frost in Colebrook?
The first hard freeze (28°F) in Colebrook typically arrives around Oct 25, per NOAA 1991–2020 climate normals — the point most tender summer crops finish. Lighter frosts usually reach a couple of weeks earlier, so watch the forecast from late summer on and harvest or cover tender plants before the first cold night.
What vegetables grow in Colebrook?
Colebrook's zones 4a-5b support a wide range — strong performers include Apple, Sugar Maple, Blueberry, Potato, and Lilac. What actually takes on any one site comes down to its soil, sun, and drainage, and we score each plant against the real conditions at your address.
Which hardiness zone is Colebrook, really?
Officially, Colebrook sits in USDA zones 4a-5b (USDA PHZM 2023) — but a zone is a 30-year average of winter's coldest night across an area, and it can't see any one yard. A south-facing slope, a tree line, or a low frost pocket can shift a single site by half a zone either way, which is why neighboring gardeners often quote different numbers. We read the conditions at your exact address — soil, sun, slope, and frost — and score 1,112 plants against what's actually there.
Is the soil safe to grow vegetables in Colebrook?
The federal record around Colebrook shows 102 documented sites — 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 Colebrook?
As the season closes around the first 28°F hard freeze near Oct 25 (NOAA 1991–2020 climate normals), a few moves buy time: cover tender plants with floating row cover or an old sheet on still, clear nights, water the soil the afternoon before a freeze so it holds warmth overnight, and harvest frost-tender crops like tomatoes, peppers, and basil before the first hard night. Hardy greens and root crops shrug off light frost and often sweeten after it, so leave them in.
Everything on this page is a Colebrook average. Your yard writes its own version — we read soil, sun, drainage, and frost at your exact address. Try it for 14 days — no card required.