Greater Bangor / Penobscot Valley spans USDA hardiness zone 5a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
The Penobscot Valley's settled corridor — Bangor to Old Town river ground whose measured 177-187-day seasons run a solid week past the 2-million-acre northern-forest county around it. Well-matched crops include potato, kale, blueberry, and apple, and the gap between "grows in the area" and "grows in your yard" is closed by soil, sun, and drainage.
Greater Bangor / Penobscot Valley spans Maine.
Your yard isn't all of Greater Bangor / Penobscot Valley.
Greater Bangor / Penobscot Valley spans USDA zones 5a, but your parcel sits in exactly one — and slope, tree cover, and low spots nudge it further. 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 Greater Bangor / Penobscot Valley — soil, climate, flood, and parcel records. How we handle your address.
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Greater Bangor / Penobscot Valley — the short answer
Greater Bangor / Penobscot Valley: USDA zones 5a, 177–187 frost-free days, in Maine.
- USDA zones
- 5a
- USDA PHZM 2023, aggregated over the footprint
- Frost-free season
- 177–187 days
- NOAA Regional Climate Centers ACIS, 1991-2020
- Towns
- 7
- US Census TIGER/Line 2025
- Region type
- Town cluster
- Growable Ground growing-region registry
Region boundary: Growable Ground growing-region registry — curated county clusters, EPA Level III ecoregions, and town clusters drawn finer than any county. Where a region publishes no measured season, no season figure is shown.
Hardiness Zone Range
What Grows in Greater Bangor / Penobscot Valley
Plants matched to Greater Bangor / Penobscot Valley's USDA zones 5a, ordered by how much hardiness margin each has across the region — the ones with room to spare at both ends of this band lead. Each links to its full growing profile.
Native Plants of Greater Bangor / Penobscot Valley
Plants the USDA PLANTS Database documents as native and present in this region’s state, kept only where the published hardiness range meets Greater Bangor / Penobscot Valley’s USDA zones 5a — closest range match first. Presence is recorded by state, so a plant can be documented across the state and still be scarce in your corner of the region.
The ground around Greater Bangor / Penobscot Valley
The USDA soil survey maps this ground county by county. These are those records weighted by land area across the county containing Greater Bangor / Penobscot Valley — the ground Greater Bangor / Penobscot Valley sits in, read at the only grain the survey publishes.
In the county containing Greater Bangor / Penobscot Valley, the ground is predominantly Spodosols, at 58% of mapped acres, followed by Inceptisols (34%), Histosols (6%) and Entisols (1%). The most extensive named soils are Plaisted, Monarda, and Burnham.
24% of those acres are poorly drained, and another 17% well drained, 15% moderately well drained. Topsoil pH runs 4.3–5.1 in that county’s own record. 4% of the footprint is classed prime farmland.
Soil order
Spodosols
Drainage
Poorly drained
Topsoil pH
4.3–5.1
Hydric soils
36%
Soil changes across a driveway, so which of these your own ground sits on is a parcel question rather than a regional one. soil types explained.
USDA NRCS SSURGO via Soil Data Access
What this means for growing in Greater Bangor / Penobscot Valley
The soil survey reads this ground county by county, and the readings above are the record for the county containing Greater Bangor / Penobscot Valley. Here is what they mean for a garden here — and the move an experienced grower makes about each one.
Drainage
From county records24% of the mapped acres across the county containing Greater Bangor / Penobscot Valley are poorly drained — ground that sheds water slowly. The survey maps this ground county-wide, so it describes the setting Greater Bangor / Penobscot Valley sits in rather than the valley floor alone.
Beds can stay saturated for days after heavy rain, and the roots of most vegetables, berries, and fruit trees suffocate or rot in soil that never drains.
Raised beds or mounded rows lift roots above the wet zone; choose water-tolerant crops for the lowest spots.
USDA NRCS SSURGO
Surface pH
From county recordsTopsoil across the county containing Greater Bangor / Penobscot Valley runs pH 4.3–5.1 — acidic in the one record covering it.
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
Safe to Grow Here?
What the federal record shows across Greater Bangor / Penobscot Valley — and how to grow with it.
Across Penobscot County, which contains Greater Bangor / Penobscot Valley, the federal record holds 1,140 documented sites, mostly Underground Storage Tanks (713), Brownfields (307) and Nitrate (46).
That is the containing county's count — this region is a smaller piece of that ground, so it is context, not a reading of any one lot. Open the map outlined to Greater Bangor / Penobscot Valley to see which records sit where you actually grow.
Sources Checked
Summed across the county containing Greater Bangor / Penobscot Valley
A note from Gnorman
What an experienced grower watches for around here
In and around Greater Bangor / Penobscot Valley, two things run higher than the national average across the county containing Greater Bangor / Penobscot Valley — Superfund (16 sites) and Underground Storage Tanks (713 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.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
Your land is one point inside Greater Bangor / Penobscot Valley
Everything above resolves to Greater Bangor / Penobscot Valley as a whole — a footprint spanning USDA zones 5a. Your parcel sits in exactly one of them. 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 region 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 regional average.
Your Lot vs Greater Bangor / Penobscot Valley Average
Greater Bangor / Penobscot Valley Average
- ●USDA Zones 5a, averaged across Greater Bangor / Penobscot Valley
- ●One soil character for all of Greater Bangor / Penobscot Valley
- ●State-average frost dates
YOUR Parcel
- ✓Your exact zone, not Greater Bangor / Penobscot Valley's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Greater Bangor / Penobscot Valley
Pull a site-specific report for your exact address in Greater Bangor / Penobscot Valley — soil, sun, drainage, frost risk, contamination, and scored plant recommendations.
Three things about your lot that Greater Bangor / Penobscot Valley averages can't show:
We read public map data around Greater Bangor / Penobscot Valley — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not Greater Bangor / Penobscot Valley average
How we know this about Greater Bangor / Penobscot Valley
The boundary: the region's own towns — a footprint finer than any county, because the county average would misread this microclimate. Growing regions have no official boundary, so this footprint is our published one, and every figure on this page was measured over the towns inside it rather than borrowed from the state around it.
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, aggregated across the footprint; the growing season from NOAA Regional Climate Centers ACIS 1991–2020 28°F normals, read at each member’s own record; boundaries from US Census TIGER/Line 2025; the contamination record from the federal sources named in that beat above; the soil from the USDA NRCS SSURGO survey, read at each member county’s own record and weighted to this footprint by land area. Where a member carries no record of its own, it is absent from the figure rather than filled in.
Common questions about Greater Bangor / Penobscot Valley
What hardiness zone is Greater Bangor / Penobscot Valley?
Greater Bangor / Penobscot Valley spans USDA hardiness zones 5a, aggregated from the USDA Agricultural Research Service Plant Hardiness Zone Map 2023 across the region's own towns. Zones reflect average annual extreme minimum temperatures from 1991–2020 data.
How long is the growing season in Greater Bangor / Penobscot Valley?
Measured between 28°F hard freezes, Greater Bangor / Penobscot Valley's towns mostly run 179 to 183 frost-free days, median 181 (NOAA Regional Climate Centers ACIS, 1991–2020, over 7 member towns). That 4-day spread is the honest read — no single season describes 7 towns, and each town guide below carries its own.
When does frost risk end in Greater Bangor / Penobscot Valley?
Across Greater Bangor / Penobscot Valley, the middle half of member towns see their last 28°F hard freeze between Apr 21 and Apr 23 (median Apr 21), and their first fall freeze between Oct 18 and Oct 21. Those are hard freezes, not the last light frost: tender transplants wait for about May 12, and elevation decides which end of a 2-day spread you garden in.
What grows well in Greater Bangor / Penobscot Valley?
Greater Bangor / Penobscot Valley's conditions suit plants such as Potato, Kale, Blueberry, Apple, White Pine. What actually thrives on any one site still turns on its specific soil, sun, and drainage — we score each plant against the real conditions at your address.
How is Greater Bangor / Penobscot Valley defined?
Greater Bangor / Penobscot Valley is a true microclimate — smaller than the county that contains it, with a growing reality of its own. So this page is built from the region's own 7 towns, each carrying its own hardiness zone and frost record, rather than from a county average measured somewhere else.
Which states does Greater Bangor / Penobscot Valley cover?
Greater Bangor / Penobscot Valley spans Maine. Each state's full growing guide is linked on this page.
What other growing regions cover the same states?
Midcoast Maine, Casco Bay / Greater Portland, Down East Maine, Western Maine Mountains (High Peaks / Rangeley Lakes), Aroostook County, and Kennebec Valley (Central Maine) share at least one state with Greater Bangor / Penobscot Valley. Growing regions overlap and interlock — a single address can sit inside more than one, which is why the precise read is always the parcel, not the region.
What this page reads at Greater Bangor / Penobscot Valley’s own scale
6 of the readings below were taken at Greater Bangor / Penobscot Valley's own scale — the zone 5a band across its footprint, a median 181-day season across its 7 towns and 1,140 documented federal contamination records across its one county, 1,140 of them in Penobscot County alone; one is borrowed from a wider read, named and linked below.
Measured here
- The USDA hardiness band 5a aggregated across all 7 towns in the footprintUSDA PHZM 2023
- The boundary itself — the 7 towns this region is curated fromGrowable Ground subregion registry
- The growing character that makes this region distinct from the states it crossesGrowable Ground subregion registry
- The 28°F season across the footprint — the middle half of its 7 towns run 179 to 183 frost-free days, median 181NOAA Regional Climate Centers ACIS, 1991-2020
- The federal contamination record over the whole footprint — 1,140 documented federal contamination records across its one county, 1,140 of them in Penobscot County aloneEPA, USGS and USDA federal site records
- The soil order mix across the footprint — 58% Spodosols, topsoil pH 4.3–5.1, area-weighted across its one mapped countyUSDA NRCS SSURGO
Inherited from a wider read
- The candidate plant list — its state's curated sets, merged and filtered to zones 5afrom Maine
What this page can’t tell you
- Which end of the 4-day range your ground sits at — 179 days at one extreme, 183 at the other, decided mostly by elevationfrost dates explained →
- Which of those soils your own ground sits on — the survey maps them county-wide, and they change across a drivewaysoil types explained →
- The soil pH, drainage, sun hours, and frost pockets on one specific lotwhy one lot differs from the next →
Explore Greater Bangor / Penobscot Valley
State growing guides
Towns in this region
The county containing this region
Other growing regions across Maine
Maine's rocky-peninsula coast, where the Atlantic tempers winters into USDA zones 5b–6a and stretches the frost-free season to roughly 186–222 days — Knox County's 222-day window is the longest of any county in the state.
Coastal southern Maine around Portland and Casco Bay — the three counties of the Census Portland-South Portland metro (Cumberland, Sagadahoc, York) all share USDA hardiness zone 5b and a growing season of roughly 166 to 188 frost-free days, the ocean holding the first fall freeze off until late October.
Down East Maine spans Hancock and Washington counties along the state's easternmost coast, where a maritime-tempered USDA zone 5b holds a short frost-free season of roughly 178 to 188 days.
The only true mountain regime in Maine. Franklin County runs just a 143-day growing season in zone 4b — the coldest, shortest-season part of the state outside Aroostook — because high elevation plus valley cold-air pooling in the High Peaks and Rangeley Lakes country pushes last frosts into late May and first frosts into early September. That is a short, sharp mountain season that neither Maine's milder coast nor Aroostook's flat lowland potato country shares, and it changes what you can start from seed, when you transplant, and which long-season crops need a head start indoors.
Northern Maine's vast potato country — hard winters, a short intense summer, and deep glacial loams behind one of the country's great seed-potato regions.
Central Maine's inland exception to an all-coastal map. Where the Kennebec River threads Augusta, Waterville and Gardiner, the corridor holds Zone 5b with roughly 190 frost-free days — one of the warmer pockets of Maine's continental interior, and warmer than the 4b uplands that ring it. But "continental" is the operative word: with no Atlantic moderation like a Casco Bay parcel gets, growers here trade steadier summer heat for harder radiational-frost nights that can fall well below the nominal-zone number on a clear, still spring or fall evening. Read your own cold pockets off the river — not just the corridor's headline zone.