Hubbard squash (Cucurbita maxima), photographi

Can I Grow Hubbard Squash in Maine?

USDA Zones 3b-7a · Plant zone range 2-11

Yes — Strong Match

Hubbard squash (zones 2-11) covers every zone Maine contains (3b-7a), so hardiness is not what limits it anywhere in the state.

Hubbard Squash in Maine — the short answer

Hubbard Squash in Maine: hardy in zones 2–11, full sun, against a state median of ~182 frost-free days.

Plant zones
2-11
Manual horticultural correction (source not retained); NC State Extension and Missouri Botanical Garden, with the remaining rows from other published sources or Growable Ground compilation
Maine zones
3b-7a
USDA PHZM 2023
Frost window
Apr 16 - May 3 – Oct 10 - Oct 24
NOAA RCC ACIS 1991-2020, 28°F
Shortest county season
143 days
NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
Days to maturity
100 days
Growable Ground Plant Database

Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — per-field provenance varies and is published with the dataset.

Score your parcel · free

Your yard isn't the whole zone.

Maine spans zones 3b-7a, but your yard has its own microclimate — slope, trees, and low spots shift frost and sun across a single parcel. Enter your address and we'll score hubbard squash against your land's actual soil, sun, and frost.

We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.

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Maine is not one climate

A single Maine answer averages 16 counties whose growing seasons are 79 days apart — from 143 frost-free days in Franklin County to 222 in Knox County. Which end of that your land sits nearer changes what hubbard squash can finish before the first hard freeze.

143 daysFranklin County222 daysKnox County

The middle half of 16 counties runs 154191 days, with a median of 178 days — a 79-day span end to end.

Measured across 16 Maine counties. NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze. Quartiles are order statistics — every figure shown is a value a real county recorded, not an interpolation. Your own site sits somewhere inside this range; a parcel report resolves where.

Where in Maine Fits Best

Even within Maine's zones 3b-7a, county microclimates differ enough to change what thrives. These counties carry the closest zone match for hubbard squash (USDA PHZM 2023):

Zone Comparison

Hubbard Squash Needs

  • USDA Zones: 2-11
  • Frost-Free Days: 80+
  • Sun: Full Sun
  • Mature size: 2 ft tall
  • Picking window: ~18 days of harvest
  • Drought tolerance: Low

Maine Has

  • USDA Zones: 3b-7a
  • Last Hard Freeze (28°F): Apr 16 - May 3
  • First Hard Freeze (28°F): Oct 10 - Oct 24
  • Annual Rainfall: 36-50 inches
  • Common Soils: Glacial till, Sandy loam, Rocky loam

Plant Zone Range (zones 2-11)

2a
11b
3a (Cold)13b (Hot)

Preferred Soil pH

3.5 (Acidic)7.0 (Neutral)9.0 (Alkaline)
Highlighted range: pH 5.08.5

Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS, and university Extension sources — per-field provenance varies and is published with the dataset. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.

When to Plant Hubbard Squash in Maine

The frost window

Across Maine, the last spring hard freeze (28°F) clears between Apr 16 and May 3, and the first fall hard freeze lands between Oct 10 and Oct 24 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 160-day window you can count on — up to 191 days on a mild site in a kind year. That marks the hard freeze, not the last light frost, so tender transplants usually wait another 2-3 weeks.

When to start the seed

Those dates are when hubbard squash goes out, not when it starts. It is sown under cover about 3 weeks ahead, so counting back from Maine's late-side last freeze of May 3 is what fixes your sowing date — and a yard that clears frost earlier than the state's late date starts earlier still.

Days to maturity vs. the window

At 100 days to maturity (Growable Ground Plant Database), counting from the last hard freeze it ripens with 60 days to spare even in Maine's tightest freeze scenario — room for a later start or a second sowing.

Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: Growable Ground Plant Database — frost-free days from FAO ECOCROP, days to harvest from university Extension production guides, and growing-degree-day and chill-hour minimums that are compilation estimates rather than published figures. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.

Growing Season Fit

The zone check says hubbard squash survives winter here. Whether the season is long enough — and warm enough — is a different question.

Frost-free days

Hubbard Squash wants 80+ frost-free days; a typical Maine site sees ~182 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.

Growing degree days

Hubbard Squash needs ~2200 GDD (base 50°F) to ripen. The state median runs ~1450 GDD (from PRISM 1991-2020 climate normals), so Maine's typical season runs short on heat — pick a south-facing site and consider season extension.

GDD and chill-hour figures are computed from PRISM 1991-2020 monthly climate normals; frost-free days from NOAA Regional Climate Centers ACIS, 1991-2020. Each is the state median across its counties (P25/P75 span the within-state spread). Hardiness-zone range is USDA PHZM 2023.

Soil + Drainage Fit

Hubbard Squash tolerates a wide pH range (pH 5-8.5) — 3.5 units, acid ground through alkaline — so soil acidity is rarely what limits it in Maine. A soil test is still worth having, but for what else it tells you about this site, not to clear this plant. It will grow across that whole span, but it does best between pH 5.5 and 7.5 — worth knowing before you decide whether a Maine soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Maine site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.

Plant pH requirements: FAO ECOCROP and USDA PLANTS, with the remaining rows from other published sources or Growable Ground compilation. Drainage: FAO ECOCROP, with the remaining rows from other published sources or Growable Ground compilation. Maine soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.

Before you plant hubbard squash for food

Anything you grow to eat takes up what is in the ground it grows in, so what is on record near you is worth knowing before hubbard squash goes in. What follows is Maine’s documented federal record at state scale — a screening signal, not a soil test, and not a statement about any one lot.

Safe to Grow Here?

What the federal record shows across Maine — and how to grow with it.

Federal record: High

We checked the federal record across Maine10,103 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

High163Moderate3,125Low6,815

Highest-Severity Sites

Acton Area Mines
Mining Sites · Past Producer
Acton Mine
Mining Sites · Past Producer
Argonaut Mine
Mining Sites · Past Producer
Belfast Water District
PFAS Sampling · PFAS Detected
Brunswick Naval Air Station
Superfund · Superfund NPL

Know Before You Grow

  • Underground tanks leak petroleum as they age — near a former filling station, test the soil.
  • Near a brownfield, raised beds of imported soil give your food clean ground.
  • On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.

Sources: EPA, USGS1.8M documented sites tracked nationwide across 9 federal source types.

What Else to Consider for Hubbard Squash in Maine

Zone compatibility tells you about winter cold survival — but Maine growers also need to think about:

Very short growing season (100-140 frost-free days)

Rocky glacial soils require significant clearing

Harsh winters with heavy snow and ice

What to actually do about these — and the constraints that apply to every Maine grower, not just hubbard squash — is covered on the Maine growing guide.

Timing shifts within Maine

Hubbard Squash needs about 80 days of frost-free season to complete its cycle. Even Franklin County — Maine’s shortest season at 143 frost-free days — clears that by 63 days, so season length isn’t the constraint anywhere in Maine. What varies is your own parcel.

Across Maine’s 16 counties the frost-free season runs from 143 days in Franklin County to 222 days in Knox County — a spread of 79 days, which is why a single statewide planting date misleads. The median Maine county sees 182 frost-free days, leaving hubbard squash about 102 days of slack on a typical parcel — room for a second sowing where the season runs long.

County last-freeze dates and frost-free day counts: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F freeze (earlier than the folk 32°F "last frost"). Hubbard Squash's 80-day requirement: USDA PLANTS / Growable Ground plant database (minimum frost-free days). A parcel report resolves your address's own frost dates.

Pollinator + Wildlife Value

Hubbard Squash draws honeybees and native bees (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, hubbard squash can only work that bloom inside Maine's frost window — roughly 182 days, opening after the last 28°F freeze (Apr 16 - May 3) and closing at the first (Oct 10 - Oct 24), per NOAA Regional Climate Centers ACIS, 1991-2020.

Maine Cooperative Extension

For Maine-specific cultivar recommendations, planting calendars, and pest pressure for hubbard squash, the canonical source is UMaine Cooperative Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.

Is Hubbard Squash native to Maine?

No — the USDA PLANTS Database lists Hubbard Squash as introduced rather than native in the Lower 48, so it is not part of Maine's native flora. It grows here as a garden plant; pairing it with a few Maine natives keeps local pollinators fed too.

Looking for plants that belong here? The Maine growing guide lists USDA-documented natives for the state.

Native-range data: USDA PLANTS Database state-distribution records, accessed 2026-07-01.

What pests threaten hubbard squash in Maine?

Squash bug and squash vine borer are documented in Maine, and they hit hubbard squash where it counts. Here is what each one actually does — and the move that beats it.

Squash bug

Squash bug

Act on this

Squash bugs primarily attack squash and pumpkins, and the plants most at risk are the youngest and the ones in flower — the University of Minnesota notes feeding can kill young plants outright, while a larger, sturdier plant shrugs it off.

What to do: Go after where they sleep, not just the bugs. Crush the bronze egg clusters on the leaf undersides in the vein angles, drop nymphs and adults into soapy water, and clear plant debris through the season and again in fall to strip out overwintering shelter. Where squash bugs are a consistent problem, skip straw mulch — it gives them the night shelter they are looking for.

Here: In Maine that second clean-up lands around Oct 10 - Oct 24, when the first 28°F freeze typically ends the hubbard squash — pulling the vines then is what strips the overwintering shelter, and leaving them is what stocks next season.

Documented range: the United States · University of Minnesota Extension, University of Illinois IPM, University of Kentucky Entomology

The full squash bug playbook

Squash vine borer

Squash vine borer

Act on this

The wilt you notice is the larva already inside the stem. The University of Illinois puts it plainly: the squash vine borer cannot complete its development except in squash or pumpkins — and Hubbard and acorn types are the ones Kentucky and Wisconsin name as most susceptible.

What to do: Two moves beat it, and both are about timing. Float a row cover over the plants when the vines start to run — late June or early July for non-vining types — anchor the sides, and keep it on for about two weeks after the first adult moth is seen; take it off once flowers open so bees can work. Then sow a second planting of summer squash in early July: those plants mature after the moths have finished laying and come through undamaged.

Here: The escape is tight here, not impossible. Maine's ~182 frost-free days leave ~82 beyond the ~100 hubbard squash needs — enough for a late replacement sowing, not for a full second crop.

Documented range: the United States east of the Rocky Mountains · University of Minnesota Extension, University of Wisconsin–Madison Division of Extension, University of Kentucky Entomology, University of Illinois IPM

The full squash vine borer playbook

Only pests whose documented range and host relationship both trace to a primary source appear here — so a quiet section means we have nothing sourced to tell you, not that your garden is pest-free.

Common Questions About Growing Hubbard Squash in Maine

When can I plant Hubbard Squash in Maine?

Maine's last spring hard freeze (28°F) clears between Apr 16 and May 3, and the first fall hard freeze lands between Oct 10 and Oct 24 (NOAA Regional Climate Centers ACIS, 1991-2020). Time outdoor planting to after the last hard freeze for your specific site — a further two to three weeks for anything tender — and count back from those dates for transplant scheduling.

Can Hubbard Squash mature before first frost in Maine?

Yes — Hubbard Squash matures in 100 days (Growable Ground Plant Database), and Maine's dependable hard-freeze-free window runs 160 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 60 days of margin. Plant once the last hard freeze has passed — two to three weeks later for anything tender — and it ripens ahead of the first fall freeze.

What hardiness zone is Hubbard Squash grown in across Maine?

Maine spans USDA hardiness zones 3b-7a (USDA ARS PHZM 2023). Hubbard Squash carries a range of zones 2-11, so the overlap zones are where outdoor growing is most reliable.

How many frost-free days does a typical Maine site have?

A typical Maine site sees ~182 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Hubbard Squash needs 80+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date.

Is Hubbard Squash native to Maine?

No — the USDA PLANTS Database lists Hubbard Squash as introduced rather than native in the Lower 48, so it is not part of Maine's native flora. It grows here as a garden plant; pairing it with a few Maine natives keeps local pollinators fed too.

How should I amend the soil for Hubbard Squash in Maine?

Hubbard Squash tolerates pH 5-8.5 and well (dry spells) drainage (FAO ECOCROP). That is a 3.5-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a Maine site — amend for drainage and organic matter first.

Will Hubbard Squash actually grow on my specific land in Maine?

State-level zone + climate data is a sketch. A Growable Ground parcel report scores hubbard squash against your address's exact soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.

Free Report

Check your specific parcel in Maine

State-level data is a sketch. Your Growable Ground report scores hubbard squash against your parcel's exact soil, sun, drainage, and frost data — not zone averages.

Three things about your lot that Maine hubbard squash averages can't show:

Your soil pHYour frost-free days — Maine averages 182Your sun & shade

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 hubbard squash average

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