Maine spans USDA hardiness zones 3b-7a, with a growing season of about 182 frost-free days — a true four-season rhythm: spring greens, a full summer main crop, and a fall window that rewards planning.
The raw materials of the growing year here: 36-50 inches of annual rainfall, a median of roughly 1,450 growing-degree days (base 50°F), and about 2,500 winter chill hours for tree fruit. Underfoot it's mostly glacial till, sandy loam, rocky loam, and peat bog — and how those drain decides more about crop success than almost anything else. What grows in Maine depends on where in it you stand — Midcoast Maine, Casco Bay / Greater Portland, and Down East Maine each run on their own zones and frost timing. These conditions suit potato, blueberry, apple, and white pine — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Grounded inUSDA PHZM•NOAA Climate Normals•USDA NRCS SSURGO•GDD (PRISM 1991-2020 normals)•Chill hours (PRISM 1991-2020 normals)•USDA hardiness sub-region map•EPA FRS•USDA PLANTS•Growable Ground suitability scoring
Maine spans zones 3b-7a, but your yard 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 Maine — soil, climate, flood, and parcel records. How we handle your address.
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Distinct growing regions within Maine — each has its own zones, soils, and signature crops.
Maine: USDA zones 3b-7a, 143–222 frost-free days depending on the county, 16 counties.
The middle half of this state’s counties. Tender transplants usually wait 2–3 weeks past the last hard freeze. The shortest-season figure is Maine's own county record — Franklin County's measured 28°F normal, not a modeled floor.
Maine does not have one growing season. Across all 155 of its towns that carry their own 30-year record, the shortest measured season is Rangeley's at 147 days and the longest is Portland's at 224 — a 77-day spread inside one state.
Neither end is a lone reading — another 11 towns measure within 10 days of Rangeley and 4 sit within 10 days of Portland. These are real pockets, so the number to plant against is your own town's, not the state average.
NOAA Regional Climate Centers ACIS (1991–2020), 30-year daily minimum record
Zone 3b-7a is Maine's average, not your lot's — a low corner or a tree line moves it. Against Maine's 182-day season, see what your own ground reads.
One answer for Maine averages 16 counties whose growing seasons are 79 days apart — from 143 frost-free days in Franklin County to 222 in Knox County. That is the same state, measured the same way, in the same years. Which end of it your county sits nearer decides what finishes before the first hard freeze.
The middle half of 16 counties runs 154–191 days, with a median of 178 days — a 79-day span end to end.
Measured across 16 counties, each carrying its own 28°F normal. NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze. A county with no record of its own is absent from the range rather than counted as zero — nothing here is interpolated to the state. Your own site sits somewhere inside this range; a parcel report resolves where.
The middle half of Maine runs 154–191 frost-free days, and 7 of its 16 counties sit outside that — 3 on the short side, 4 on the long. A statewide planting date describes the middle well and the ends poorly, which is worth knowing before you follow one.
Under 154 frost-free days
3 counties
The end of the state that sets the planting calendar — start seed indoors here and the season stretches to meet the crop.
154–191 frost-free days
9 counties
0 of 9 shown
The middle half of the state, and the part a single statewide date describes well.
Over 191 frost-free days
4 counties
3 of 4 shown
Long enough for a second succession of a quick crop after the first comes out.
Each county is placed by its own 28°F frost-free normal (NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze), the same figure its own guide page publishes. Elevation, slope and cold-air drainage move a yard within its county as well — which is the part only your address resolves.
The soil types that dominate Maine — how each drains decides more about crop success than almost anything else. Tap any soil to learn what it is and how to work with it. Each photo is a representative profile of that soil type; the named series is where it was documented, which is often another state.
Drainage
Variable by the shovelful. Sandy till drains freely; dense, compacted till (hardpan) can perch water above it after snowmelt and heavy rain.
What thrives
Apples, stone fruits, brambles, and the whole northern vegetable garden do well on till — much of New England and the upper Midwest farms it. Deep-rooted perennials work through the stony structure happily.
Drainage
Fast. The sand fraction opens the soil up, so water moves through the root zone quickly and the surface rarely stays soggy. The trade is that nutrients ride out with the water.
What thrives
Root crops love it — carrots, potatoes, radishes, and onions size up cleanly in ground they can push through. Melons, sweet potatoes, asparagus, and most herbs appreciate the warmth and the drainage.
Loam threaded with stones — the signature of ground where glaciers, mountains, or shallow bedrock keep feeding rock into the topsoil. Every New England stone wall started as a rocky-loam garden bed.
Drainage
Good. The stones keep channels open through the profile, and rocky ground rarely waterlogs.
What thrives
Fruit trees, brambles, asparagus, herbs, and deep-rooted perennials thread between the stones happily. Root crops that need clean, straight runs — long carrots, parsnips — prefer a picked-over or raised bed.
Drainage
Saturated by default — peat forms precisely because water excludes the oxygen decomposition needs. Drained peat holds moisture beautifully but can stay cold late into spring.
What thrives
Acid-lovers are at home: blueberries and cranberries are the classic peatland crops, with rhododendrons, azaleas, and bog natives alongside.
Soil data: USDA NRCS SSURGO · Soil types explained
Plants well-suited to Maine's climate, soils, and growing season — each links to its full growing profile.
Almost never — the real question is what to plant next. Across Maine, cool-season planting typically opens about four weeks before the local last hard freeze — county medians put that freeze near Apr 22, with the middle half of counties between Apr 16 and May 3 (NOAA 1991–2020 climate normals). Tender transplants wait two to three weeks past it, and fall planting counts back from first freezes mostly between Oct 10 and Oct 24 — long-season crops need about 90 days of runway, quick greens only 30. Late in the year the fall bench takes over — quick greens, radishes, and garlic that repays you next summer.
The plants Maine put its name on — cultural emblems, not growing recommendations.
Pinus strobus
Designated 1895. In our plant library — see its full growing profile.
Pinus strobus
Designated 1945. In our plant library — see its full growing profile.
Wild blueberry
Designated 1991.
Plants the USDA PLANTS Database documents as native and present in Maine — a real per-state range, not just a zone match. Ordered by how closely each plant’s published hardiness range matches Maine’s zones 3b-7a, so this is a shortlist by climate fit, not a ranking of which plants matter most here. Presence is statewide, so a plant may still be uncommon in your specific county; your state’s Cooperative Extension or a native-plant society is the local authority.
US-native plants whose hardiness range overlaps Maine’s USDA zones 3b-7a but which USDA PLANTS doesn’t map to a single state range here. Zone overlap is a starting filter, not a range map.
What an experienced grower plans around here — each one has a move.
Very short growing season (100-140 frost-free days)
Fast varieties, transplants started indoors, and a cold frame on each end — Maine growers make 120 days behave like 160.
Rocky glacial soils require significant clearing
Build up instead of digging out — a raised bed over cleared ground beats a season of boulder harvesting.
Harsh winters with heavy snow and ice
Plant to your true zone and let the snow work for you — it is excellent insulation for well-chosen perennials.
For cultivar selection, pest pressure, and planting-time guidance specific to Maine, the UMaine Cooperative Extension is the authoritative local source.
Safe to Grow Here?What the federal record shows across Maine — and how to grow with it.
We checked the federal record across Maine — 10,103 documented sites across 8 of the 9 source types we track.
The most significant on record: 99 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Maine carries one of the heavier federal records we track — and that's not a verdict on your yard. Proximity to a documented site is information, not a diagnosis: nothing here says any particular parcel is affected. It does earn one concrete step — before food beds go in the ground, a professional soil test tells you exactly what you're working with, and raised beds with clean imported soil grow well almost anywhere in the meantime.
Severity Distribution
across Maine
Highest-Severity Sites
Know Before You Grow
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
Everything above resolves to Maine as a whole — a state whose own counties record seasons 79 days apart, and hardiness across zones 3b-7a. Your parcel sits at one point in that range, not in the middle of it. 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 state 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 statewide average.
State averages sketch the shape. Your soil, sun exposure, drainage, and microclimate decide what actually takes. Pull a site-specific report for your exact parcel.
Enter your address. We read your soil, sun, drainage, and frost dates, then score 1,086 plants against the real conditions on your land.
Three things about your lot that Maine averages can't show:
We read public map data around Maine — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Maine average
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read per county and aggregated to the state band; the growing season from NOAA Regional Climate Centers ACIS 1991–2020 28°F normals, read at each county’s own record; rainfall from NOAA Climate Normals; soils from USDA NRCS SSURGO; boundaries from US Census TIGER/Line 2025; the contamination record from the federal sources named in that beat above. Where a county carries no record of its own, it is absent from the figure rather than filled in.
Maine spans USDA hardiness zones 3b-7a — which is to say winter's coldest night runs from about −35°F to 5°F depending where in Maine you are, averaged over 1991–2020 (USDA PHZM 2023).
Almost never — the real question is what to plant next. Across Maine, cool-season planting typically opens about four weeks before the local last hard freeze — county medians put that freeze near Apr 22, with the middle half of counties between Apr 16 and May 3 (NOAA 1991–2020 climate normals). Tender transplants wait two to three weeks past it, and fall planting counts back from first freezes mostly between Oct 10 and Oct 24 — long-season crops need about 90 days of runway, quick greens only 30. Late in the year the fall bench takes over — quick greens, radishes, and garlic that repays you next summer.
Across Maine, the middle half of counties see their last hard freeze (28°F) between about Apr 16 and May 3, with a county median near Apr 22 (NOAA 1991–2020 climate normals). 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 13.
Measured between 28°F hard freezes, growing seasons across Maine's counties mostly run about 159 to 191 days, with a county median near 182 (NOAA 1991–2020 climate normals). Tender crops get a somewhat shorter practical window, since lighter frosts reach a few weeks past the hard-freeze dates on both ends.
Maine's zones 3b-7a support a wide range — strong performers include Potato, Blueberry, Apple, White Pine, and Kale. 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.
Officially, Maine spans USDA zones 3b-7a (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 1,086 plants against what's actually there.
The federal record across Maine runs heavier than most — 10,103 documented sites, mostly Underground Storage Tanks entries (6,003) — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
Start with three facts. Maine spans USDA zones 3b-7a, which sets what survives winter; last hard freezes range from about Apr 16 to May 3 across its counties (NOAA 1991–2020 climate normals); and 10,103 documented sites sit on the federal record here, so a soil test before food beds is the smart first step. From there, matching plants to your actual soil and sun is the fun part.
Everything above is measured at Maine's scale — its 3b-7a band and its 182-day season. Your yard writes its own version of Maine's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
6 of the readings below were taken at Maine's own scale — the full zone 3b-7a span inside its borders, the 4 soil types that dominate its ground and 10,103 documented sites on its federal record; anything it cannot resolve at this scale is named below.
Measured here
What this page can’t tell you
Explore growing conditions by county — each has its own zone range and land area.
Explore growing conditions by city or town in Maine.
Maine shares its dominant growing region with these states — a useful comparison if you're weighing where a crop will behave the same way.
