Caribou, Maine, sits in USDA hardiness zone 4a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
These conditions suit cabbage, cranberry, turkish rocket, and collard greens — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Even in Caribou, 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 Caribou 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 Caribou — soil, climate, flood, and parcel records. How we handle your address.
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Caribou — the short answer
Caribou, Maine: USDA zone 4a, about 162 days between hard freezes, across 51K acres of city.
- USDA zone
- 4a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 30
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 9
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~162
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 51K 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 4a is Caribou's average, not your lot's — a low corner or a tree line moves it. Against Caribou's 162-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Caribou
Each reading below is measured for Caribou itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredCaribou runs about 162 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
MeasuredCaribou sits in USDA hardiness zone 4a.
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 Caribou is in
Caribou sits in the Acadian Plains and Hills — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Caribou's own centroid rather than borrowed from Aroostook County.
What Grows in Caribou
Every plant below cleared Caribou's own zone 4a and its 162-day season. Each card opens that plant's Maine profile. How we score.
Is it too late to plant in Caribou?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Apr 2; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 30 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 9 — long-season crops need about 90 days of runway, quick greens only 30. The tail of the season still works: sixty-day crops into late summer, quick greens after, garlic last of all.
What's on the federal record near Caribou
Closest first, within ~10 miles of Caribou. Listing isn't leaking, and distance isn't exposure.
- SNOW BROTHERSUnderground Storage Tanks · 1.1 mi
- GRIMES WAREHOUSEToxics Release Inventory · 1.1 mi
- ARW 902Nitrate · 1.2 mi
- EDGECOMB, BURNICE EUnderground Storage Tanks · 1.7 mi
- TRI COMM RECYL & SANITARY LDFLUnderground Storage Tanks · 1.7 mi
- LAVOIE, MICHAEL SUnderground Storage Tanks · 1.7 mi
- CUSHMAN, CALDON HUnderground Storage Tanks · 1.9 mi
- M SKONIECZNY & SONUnderground Storage Tanks · 2.4 mi
- CAMPBELL, PETER JUnderground Storage Tanks · 2.4 mi
- SAMS SPORT & SKIUnderground Storage Tanks · 3.2 mi
- NORTHEASTERN SUPPLY COUnderground Storage Tanks · 3.2 mi
- MIKE'S QUICK STOP & DELIUnderground Storage Tanks · 3.3 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Caribou'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 Caribou.
Sources Checked
within ~10 miles of Caribou
Severity Distribution
within ~10 miles of Caribou
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Caribou, two things run higher than the national average within ~10 miles of Caribou — Superfund (4 sites) and Underground Storage Tanks (174 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Caribou
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 Caribou average
Your land is one point inside Caribou
Everything above resolves to Caribou as a whole — one PHZM band and one 28°F frost record, read across 51K 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 city 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 Caribou Average
Caribou Average
- ●USDA Zones 4a, averaged across Caribou
- ●One soil character for all of Caribou
- ●Frost dates read at Caribou's scale: Apr 30 to Oct 9
YOUR Parcel
- ✓Your exact zone, not Caribou's 4a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Caribou
Pull a site-specific report for your exact address in Caribou, Maine — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Caribou averages can't show:
We read public map data around Caribou — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Caribou average
How we know this about Caribou
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Caribou’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 city grain anywhere on this page — there is no city-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 Caribou
When does frost risk typically end in Caribou?
The last hard freeze (28°F) in Caribou typically lands around Apr 30, 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 21.
When is the first frost in Caribou?
The first hard freeze (28°F) in Caribou typically arrives around Oct 9, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 25, so the watching starts about Sep 9 — about 162 days after the spring freeze cleared.
How long is the growing season in Caribou?
Measured between 28°F hard freezes, Caribou sees about 162 frost-free days — roughly Apr 30 through Oct 9, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 21 to Sep 25, about 127 days.
Is the soil safe to grow vegetables in Caribou?
The federal record around Caribou is a meaningful one — 252 documented sites, mostly Underground Storage Tanks entries (174), the nearest Underground Storage Tanks record about 1.1 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 Caribou?
From about Sep 9 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 9 (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 9. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Caribou's scale — its 4a band and its 162-day season. Your yard writes its own version of Caribou'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 Caribou’s own scale
6 of the readings below were taken at Caribou's own scale — its own ~162-day season between 28°F freezes, the 50,746 acres it covers and 252 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Caribou's own USDA hardiness band, zones 4aUSDA PHZM 2023
- Caribou's own 28°F hard-freeze dates, about Apr 30 and Oct 9 and the ~162-day span between themNOAA 1991–2020 Climate Normals
- 252 documented contamination sites on the federal record near Caribou, the closest Underground Storage Tanks record about 1.1 miles out from the town centreFederal environmental registers
- Caribou's boundary and the 50,746 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4a and a ~162-day seasonGrowable Ground crop-matching engine
- The ecoregion at Caribou's own centroid, the Acadian Plains and HillsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Caribou's 50,746 acres read through its county's SSURGO summaryfrom Aroostook County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Aroostook County
- The growing challenges every Maine grower plans around — written at state scale, so they stay on the state guidefrom Maine
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Aroostook County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Caribou's 50,746 acreswhy one lot differs from the next →
- Which side of Caribou you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 50,746 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 1.1 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 Caribou-wide figureread your own land →
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