What Grows in Portland, Maine

USDA Zones 6a · 14K acres

Portland, Maine, sits in USDA hardiness zone 6a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.

Expect cabbage, blueberry, lavender, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.

Score your parcel · free

Even in Portland, 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 Portland 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 Portland — soil, climate, flood, and parcel records. How we handle your address.

No card required · your full report in seconds

Portland — the short answer

Portland, Maine: USDA zone 6a, about 224 days between hard freezes, across 14K acres of city.

USDA zone
6a
USDA PHZM 2023
Last hard freeze (28°F)
Apr 4
NOAA 1991–2020 Climate Normals, 28°F — this town
First hard freeze (28°F)
Nov 14
NOAA 1991–2020 Climate Normals, 28°F — this town
Days between freezes
~224
NOAA 1991–2020 Climate Normals, 28°F — this town
City area
14K 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

6a6a
3a (Cold)13b (Hot)
Your USDA zone 6aSee the zone map →

Zone 6a is Portland's average, not your lot's — a low corner or a tree line moves it. Against Portland's 224-day season, see what your own ground reads.

Soil varies lot by lot — soil types explained.

What this means for growing in Portland

Each reading below is measured for Portland itself — here is what it means for a garden here, and the move an experienced grower makes about it.

Season length

Measured

Portland runs about 224 days between hard freezes — a long growing season.

There is slack for succession plantings and slow-finishing crops: many vegetables can be sown twice, and the heat-lovers have time to ripen fully.

Plan a second sowing of quick crops after the first comes out, and use the fall window most gardeners let sit idle.

Making the most of a long season

NOAA 1991–2020 Climate Normals

Winter hardiness

Measured

Portland sits in USDA hardiness zone 6a.

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.

How hardiness zones work

USDA PHZM 2023

What Grows in Portland

Every plant below cleared Portland's own zone 6a and its 224-day season. Each card opens that plant's Maine profile. How we score.

cabbage, photograph
Growing cabbage in MaineZones 2–11Portland's 6a — 4 zones of cold margin.
blueberry, photograph
Maine blueberry guideZones 3–8Portland's 6a — 3 zones of cold margin.
lavender, photograph
Lavender in MaineZones 5–8Portland's 6a — 1 zone of cold margin.
collard greens, photograph
Collard greens: Maine growing notesZones 2–11Portland's 6a — 4 zones of cold margin.
hazelnut, photograph
Growing hazelnut in MaineZones 4–9Portland's 6a — 2 zones of cold margin.
California poppy, photograph
Maine california poppy guideZones 6–10Portland's 6a is its exact cold limit.
garlic, photograph
Garlic in MaineZones 2–10Portland's 6a — 4 zones of cold margin.
apple, photograph
Apple: Maine growing notesZones 3–8Portland's 6a — 3 zones of cold margin.
St. Johns wort, photograph
Growing st. johns wort in MaineZones 3–8Portland's 6a — 3 zones of cold margin.
kale, photograph
Maine kale guideZones 2–11Portland's 6a — 4 zones of cold margin.
pear, photograph
Pear in MaineZones 4–8Portland's 6a — 2 zones of cold margin.
Turkish rocket, photograph
Turkish rocket: Maine growing notesPortland's 224 days clear the ~90 it needs.
lentil, photograph
Growing lentil in MaineZones 2–11Portland's 224 days clear the ~70 it needs.
okra, photograph
Maine okra guideZones 2–12Portland's 224 days clear the ~50 it needs.
potato, photograph
Potato in MaineZones 2–11Portland's 6a — 4 zones of cold margin.
hosta, photograph
Hosta: Maine growing notesZones 3–8Portland's 6a — 3 zones of cold margin.
sunflower, photograph
Growing sunflower in MaineZones 2–11Portland's 224 days clear the ~70 it needs.
azalea, photograph
Maine azalea guideZones 4–8Portland's 6a — 2 zones of cold margin.
hops, photograph
Hops in MaineZones 3–8Portland's 6a — 3 zones of cold margin.
iris, photograph
Iris: Maine growing notesZones 3–10Portland's 6a — 3 zones of cold margin.
French marigold, photograph
Growing french marigold in MainePortland's 224 days clear the ~50 it needs.
lilac, photograph
Maine lilac guideZones 4–10Portland's 6a — 2 zones of cold margin.
American bittersweet, photograph
American bittersweet in MaineZones 3–8Portland's 6a — 3 zones of cold margin.
tulip, photograph
Tulip: Maine growing notesZones 6–8Portland's 6a is its exact cold limit.
American elm, photograph
Growing american elm in MaineZones 3–9Portland's 6a — 3 zones of cold margin.
Ethiopian mustard, photograph
Maine ethiopian mustard guideZones 4–10Portland's 6a — 2 zones of cold margin.
Kentucky bluegrass, botanical illustration
Kentucky bluegrass in MaineZones 2–7Portland's 6a — 4 zones of cold margin.
Douglas fir, photograph
Douglas fir: Maine growing notesZones 4–10Portland's 6a — 2 zones of cold margin.
alfalfa, photograph
Growing alfalfa in MaineZones 2–10Portland's 224 days clear the ~100 it needs.
Canada wild rye, photograph
Maine canada wild rye guideZones 3–8Portland's 6a — 3 zones of cold margin.

Is it too late to plant in Portland?

For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Mar 7; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 4 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 14 — long-season crops need about 90 days of runway, quick greens only 30. Here the season winds down slowly: late sowings, a real autumn harvest, and garlic in the ground before the first hard freeze.

Documented around Portland

Survey cells within 31 miles of Portland checked for spotted lanternfly, none carrying a detection — a surveyed negative, not an absence of looking. Nearest documented record 60 miles off. What to watch for.

What's on the federal record near Portland

Closest first, within ~10 miles of Portland. Listing isn't leaking, and distance isn't exposure.

  1. MAIDEN COVE PUMPING STATIONUnderground Storage Tanks · 1.5 mi
  2. FORMER PEAKS ISLAND MIL RESUnderground Storage Tanks · 1.6 mi
  3. PEAKS ISLAND WASTEWATER TREATMENT FACILITYBrownfields · 1.7 mi
  4. LIONEL PLANTE ASSOCIATESUnderground Storage Tanks · 1.8 mi
  5. OTTAWA RD PUMPING STATIONUnderground Storage Tanks · 2.0 mi
  6. FORMER DEPT OF DEFENSE SITEUnderground Storage Tanks · 2.0 mi
  7. CAPE ELIZABETH SHORE RD IRVINGUnderground Storage Tanks · 2.0 mi
  8. CAPE ELIZABETH GARAGE IRVING GAS STATIONBrownfields · 2.0 mi
  9. PEAKS ISLAND CENTRAL OFFICEUnderground Storage Tanks · 2.2 mi
  10. JACKSONS SERVICE CENTER INCUnderground Storage Tanks · 2.2 mi
  11. DUVALS SERVICE CENTERUnderground Storage Tanks · 2.3 mi
  12. FAMILY DENTAL OFFICEUnderground Storage Tanks · 2.4 mi

6 more sites are on the record inside the same radius.

Measured from Portland'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 Portland.

Total Sites

893

within ~10 miles of Portland

Risk Level

Elevated

Highest-severity

12 Superfund sites (none NPL-listed)

Sources Checked

within ~10 miles of Portland

Severity Distribution

within ~10 miles of Portland

High0Moderate173Low720

Highest-Severity Sites

2 Meadow Drive LLC
Underground Storage Tanks · Open UST(S)
697 Puffin Stop Corp
Underground Storage Tanks · Open UST(S)
7 Eleven 32531
Underground Storage Tanks · Open UST(S)
7 Eleven 32532
Underground Storage Tanks · Open UST(S)
7 Eleven 32538
Underground Storage Tanks · Open UST(S)

A note from Gnorman

What an experienced grower watches for around here

In and around Portland, Superfund runs higher than the national average — 12 sites within ~10 miles of Portland. That's not a problem with your land — it's information about it.

Superfund: Superfund sites represent the most severe contamination in the federal system.

Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).

build up with a clean-soil raised bedread your soil before you plantSee what's flagged near Portland
Explore the contamination map around Portland·Maine Growing Guide
Free Report

Check your specific parcel in Portland

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 Portland average

Your land is one point inside Portland

Everything above resolves to Portland as a whole — one PHZM band and one 28°F frost record, read across 14K 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 Portland Average

Portland Average

  • ●USDA Zones 6a, averaged across Portland
  • ●One soil character for all of Portland
  • ●Frost dates read at Portland's scale: Apr 4 to Nov 14

YOUR Parcel

  • ✓Your exact zone, not Portland's 6a
  • ✓Your SSURGO soil type & pH
  • ✓Your sun exposure, cast in 3D

See MY Growing Report

Free Report

Read your specific parcel in Portland

Pull a site-specific report for your exact address in Portland, Maine — soil, sun, drainage, frost risk, and scored plant recommendations.

Three things about your lot that Portland averages can't show:

Your soil pHYour frost-free days — Portland averages 224Your sun & shade

We read public map data around Portland — soil, climate, flood, and parcel records. How we handle your address.

25+ data sources read at your address, not the Portland average

How we know this about Portland

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 Portland’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 Portland

When does frost risk typically end in Portland?

The last hard freeze (28°F) in Portland typically lands around Apr 4, 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 Apr 25.

When is the first frost in Portland?

The first hard freeze (28°F) in Portland typically arrives around Nov 14, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 31, so the watching starts about Oct 15 — about 224 days after the spring freeze cleared.

How long is the growing season in Portland?

Measured between 28°F hard freezes, Portland sees about 224 frost-free days — roughly Apr 4 through Nov 14, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 25 to Oct 31, about 189 days.

Is the soil safe to grow vegetables in Portland?

The federal record around Portland is a meaningful one — 893 documented sites, mostly Underground Storage Tanks entries (484), the nearest Underground Storage Tanks record about 1.5 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 Portland?

From about Oct 15 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 Nov 14 (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 Nov 14. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.

Everything above is measured at Portland's scale — its 6a band and its 224-day season. Your yard writes its own version of Portland'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 Portland’s own scale

6 of the readings below were taken at Portland's own scale — its own ~224-day season between 28°F freezes, the 13,786 acres it covers and 893 documented sites around it; 2 are borrowed from a wider read, named and linked below.

Measured here

  • Portland's own USDA hardiness band, zones 6aUSDA PHZM 2023
  • Portland's own 28°F hard-freeze dates, about Apr 4 and Nov 14 and the ~224-day span between themNOAA 1991–2020 Climate Normals
  • 893 documented contamination sites on the federal record near Portland, the closest Underground Storage Tanks record about 1.5 miles out from the town centreFederal environmental registers
  • Portland's boundary and the 13,786 acres inside itUS Census TIGER/Line 2025
  • Which of 1,086 plants clear zones 6a and a ~224-day seasonGrowable Ground crop-matching engine
  • Lanternfly survey cells around Portland checked, none carrying a detectionlydemapr (De Bona & Helmus), 10 km survey lattice

Inherited from a wider read

  • Soil character — no town-scale survey exists, so Portland's 13,786 acres read through the state summaryfrom Maine
  • 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

  • The soil pH, drainage, sun hours, and frost pockets on any one lot among Portland's 13,786 acreswhy one lot differs from the next →
  • Which side of Portland you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 13,786 acresreading your own microclimate →
  • How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 1.5 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 Portland-wide figureread your own land →
The next step finer is your own address

More in Maine

Maine Growing Guide

Wider growing context

What grows across Maine

Portland sits outside our named growing regions, so Maine as a whole is its closest context here.

USDA PHZM•NOAA Climate Normals•US Census TIGER•PRISM Climate•EPA FRS