Aroostook County, in Maine, sits in USDA hardiness zone 4a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Among the crops suited to this profile: cabbage, cranberry, turkish rocket, and collard greens. The site-level story — soil, sun, drainage — decides the rest.
Aroostook County lies within Aroostook County — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Aroostook County holds more than one microclimate.
Soils and elevations shift across Aroostook County, so your frost dates and drainage aren't the county average. 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 Aroostook County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Aroostook County — the short answer
Aroostook County, Maine: USDA zone 4a, about 153 days between hard freezes, across 4.3M acres.
- USDA zone
- 4a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 7
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 7
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~153
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 4.3M acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are county 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 Aroostook County's average, not your lot's — a low corner or a tree line moves it. Against Aroostook County's 153-day season, see what your own ground reads.
Heat in Aroostook County
Across a year, Aroostook County accumulates about 1,450 growing degree days above 50°F, about 308 fewer than the middle Maine county — ahead of 4 of Maine’s 16 counties. Degree days are the heat a crop actually gets to work with — more of them is more room to ripen a long-season crop before the freeze closes the window.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Aroostook County
Across Aroostook County, the ground is predominantly Spodosols, where Howland, Monarda, and Plaisted are the most extensive named soil series. The soil is generally moderately well drained with a silt loam surface. Topsoil pH runs about 4.2–4.8, very strongly acidic. Rainfall drains through hydrologic group D soils.
Soil order
Spodosols
Drainage
Moderately well drained
Prime farmland
8%
Hydric soils
29%
Soil still varies lot by lot — soil types explained.
How the ground varies across Aroostook County
The USDA soil survey maps 27% of Aroostook County as moderately well drained — but another 71% drains differently: 26% poorly drained, 22% well drained.
Howland is the most extensive named soil at 12% of mapped acres, then Monarda (11%) and Plaisted (10%).
Which of them your own lot sits on is a parcel question, not a county one. Check your address for the survey at your boundary.
What this means for growing in Aroostook County
Each reading below is measured for Aroostook County itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Drainage
MeasuredThe dominant soils across Aroostook County are moderately well drained, in hydrologic group D — roughly the middle of the drainage range.
This is close to the middle most vegetables prefer: it holds enough water to carry a crop between rains without staying waterlogged. The catch is that a wet spring or a low corner can still tip it soggy.
Plant on the site as-is for most crops, but keep the lowest, slowest-draining beds for moisture-tolerant plantings.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Aroostook County runs about pH 4.2–4.8, on the acidic side.
Blueberries, potatoes, and rhododendrons thrive in it, but most vegetables start locking out nutrients below about pH 6.0 and grow pale and stunted no matter how much you feed them.
A measured lime application raises pH for the crops that need it — but test first, because the right rate depends on your own soil, not the county average.
USDA NRCS SSURGO
Wet ground
MeasuredAbout 29% of Aroostook County is mapped as hydric — wetland — soil.
If your lot falls in one of those pockets, a standard in-ground bed will fight waterlogging all season, and roots that need air will struggle.
Check how your own ground drains before you dig; raised beds or moisture-loving plantings turn a wet corner from a problem into a niche.
USDA NRCS SSURGO
Season length
MeasuredAroostook County runs about 153 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
The kind of country Aroostook County is in
Aroostook County spans 2 EPA Level III ecoregions — Acadian Plains and Hills (60%) and Northeastern Highlands (40%). Which one your land falls in changes what grows wild there and how the ground behaves, and a county-wide answer cannot tell you which.
What Grows in Aroostook County
We scored all 1,086 plants against Aroostook County's own USDA zone 4a and its own 153-day season between hard freezes, using the same matching engine that runs a full parcel report. These cleared both. Sun, soil pH and drainage vary lot by lot — those are the parcel questions below. Each card opens that plant's Maine profile.
Is it too late to plant in Aroostook County?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Apr 9; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 7 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 7 — 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.
Documented around Aroostook County
- Japanese beetle1 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Aroostook County
USGS estimates 55,625 lb of Metolachlor & Metolachlor-s on Aroostook County farmland in 2019, its largest by weight, ahead of Metolachlor-s (55,395 lb) and Metribuzin (15,207 lb).
Farmland across the whole county, not any one lot. Check your address for the site-by-site record.
Safe to Grow Here?
What the federal record shows across Aroostook County — and how to grow with it.
We checked the federal record across Aroostook County — 979 documented sites across 7 of the 9 source types we track.
The most significant on record: 6 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
There's a meaningful federal record across Aroostook County — worth a look before you plant food, not a reason to hold back from growing. Proximity to a documented site is information, not a diagnosis of any one yard. A soil test before new food beds is the sensible precaution here, and the map shows exactly which sites sit where, so you can see what's actually near you.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Aroostook County
Closest first, across Aroostook County. Listing isn't leaking, and distance isn't exposure.
- Bull HillMining · 4.3 mi
- STATION DUnderground Storage Tanks · 5.8 mi
- MOOSELEUKUnderground Storage Tanks · 6.0 mi
- IRVING FOREST PRODUCTS INCToxics Release Inventory · 6.3 mi
- LENDELL MCKEE INCUnderground Storage Tanks · 6.5 mi
- Bald MountainMining · 6.5 mi
- IRVING FOREST PRODUCTS, INC.Brownfields · 6.5 mi
- COFFIN GENERAL STOREUnderground Storage Tanks · 7.4 mi
- AJ SOUCY & SONUnderground Storage Tanks · 7.5 mi
- CYR LUMBER LOGGING SITEUnderground Storage Tanks · 7.5 mi
- FISH RIVER DISTRICTUnderground Storage Tanks · 7.5 mi
- MARTIN, JAMES JRUnderground Storage Tanks · 7.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Aroostook County'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 Aroostook County.
Sources Checked
across Aroostook County
Severity Distribution
across Aroostook County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Aroostook County, Underground Storage Tanks runs higher than the national average — 746 sites across Aroostook County. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Aroostook County
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 Aroostook County average
Your land is one point inside Aroostook County
Everything above resolves to Aroostook County as a whole — one PHZM band and one county frost record, read across 4.3M 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 county 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 county average.
Your Lot vs the Aroostook County Average
Aroostook County Average
- ●USDA Zones 4a, averaged across Aroostook County
- ●One soil character for all of Aroostook County
- ●Frost dates read at Aroostook County's scale: May 7 to Oct 7
YOUR Parcel
- ✓Your exact zone, not Aroostook County's 4a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Aroostook County
Pull a site-specific report for your exact address in Aroostook County, Maine — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Aroostook County averages can't show:
We read public map data around Aroostook County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Aroostook County average
How we know this about Aroostook County
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at county grain; hard-freeze dates from NOAA 1991–2020 28°F normals at this county’s own record where one resolves, and the labelled statewide window where none does; soils from the USDA NRCS SSURGO survey, area-weighted across the county’s own map units; boundaries and acreage from US Census TIGER/Line 2025; the contamination and pesticide records from the federal sources named in their beats above. Where Aroostook County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Aroostook County
When does frost risk typically end in Aroostook County?
The last hard freeze (28°F) in Aroostook County typically lands around May 7, 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 28.
How long is the growing season in Aroostook County?
Measured between 28°F hard freezes, Aroostook County sees about 153 frost-free days — roughly May 7 through Oct 7, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 28 to Sep 23, about 118 days.
Is the soil safe to grow vegetables in Aroostook County?
The federal record around Aroostook County is a meaningful one — 979 documented sites, mostly Underground Storage Tanks entries (746), the nearest Mining record about 4.3 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.
Everything above is measured at Aroostook County's scale — its 4a band and its 153-day season. Your yard writes its own version of Aroostook County's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
Will It Grow Here?
Zone fit is the first question — each answer below reads Maine's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Aroostook County’s own scale
9 of the readings below were taken at Aroostook County's own scale — its own ~153-day span between 28°F freezes, the 3 most extensive soil series mapped here and 979 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Aroostook County's own USDA hardiness band, zones 4aUSDA PHZM 2023
- Aroostook County's own 28°F hard-freeze dates and its ~153-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Aroostook CountyUSDA NRCS SSURGO
- 979 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Mining record about 4.3 miles outFederal environmental registers
- Aroostook County's boundary and the 4,269,577 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4a and a ~153-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Aroostook County spans, Acadian Plains and Hills the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Aroostook County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Aroostook County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Maine grower plans around — written at state scale, so they stay on the state guidefrom Maine
What this page can’t tell you
- How the season shifts across Aroostook County — the ~153 days above is one reading at its centre; the 12 towns below each carry their owntowns in this county →
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Aroostook County's 4,269,577 acreswhy one lot differs from the next →
- Which of those 979 documented sites actually reaches your soil — that needs your address, the wind, and the groundwater directionhow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — none of it survives being averaged over Aroostook Countyread your own land →