Can I Grow Turks Cap in Maine?

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

Conditional — Some Areas

Turks cap (zones 7-11) reaches only part of Maine (3b-7a): zone 7 are in range, so where you are in the state decides it.

One zone short — what would close it

Turks Cap is hardy to zone 7, and the warmest ground in Maine is zone 6 — 1 zone short. Planted in open ground it will not survive a Maine winter. To grow it here, grow turks cap in a container and move it under cover for the coldest weeks, or give it a greenhouse.

Season extension and overwintering under cover both work at this margin. How to buy the weeks →

Zone math from 7-11 (plant) against 3-6 (Maine). Lift modeled by crop_engine Sprint 20B effective_zone_modifier (+2 zones) via api/fast_sections.py Unlock Engine v2.

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Your yard isn't the whole zone.

Maine spans zones 3b-7a, but your yard sits in exactly one — and slope, tree cover, and cold-air pockets nudge it further. Enter your address and we'll score turks cap against your parcel's actual hardiness, soil, and sun.

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Zone Comparison

Turks Cap Needs

  • USDA Zones: 7-11
  • Frost-Free Days: 365+
  • Sun: Full Sun
  • Mature size: 6 ft tall
  • Picking window: ~120 days of harvest
  • Drought tolerance: High

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 7-11)

7a
11b
3a (Cold)13b (Hot)

Preferred Soil pH

3.5 (Acidic)7.0 (Neutral)9.0 (Alkaline)
Highlighted range: pH 6.08.5

Plant data: USDA PLANTS Database / Growable Ground plant catalog. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.

When to Plant Turks Cap 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.

Winter standing

Maine runs as cold as USDA zone 3, and no sourced winter-hardiness floor is on record for turks cap, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether turks cap is a permanent planting or a replant-every-spring crop for you turns on your own zone within Maine; check its hardiness range against that before treating it as long-lived ground.

Timing tuned to sub-state frost dates — Piscataquis County, not the statewide average.

Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: USDA PLANTS Database. 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 turks cap survives winter in part of Maine, not across all of it. Whether the season is long enough — and warm enough — is a different question.

Frost-free days

Turks Cap wants 365+ frost-free days; a typical Maine site sees ~182 (NOAA Regional Climate Centers ACIS, 1991-2020) — 183 days short of what it needs. A typical Maine season does not carry this crop to harvest outdoors, and a gap that size is not one an earlier sowing date or a faster cultivar closes; growing it here means growing it under cover.

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

Turks Cap likes near-neutral soil (pH 6-8.5). That's the common-ground band across Maine's glacial till and sandy loam — a soil test confirms it for your site. It will grow across that whole span, but it does best between pH 6.5 and 8 — worth knowing before you decide whether a Maine soil test result is a problem or just a number. Drainage matters: this plant wants poorly (saturated >50% of year), well (dry spells). If your Maine site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.

Your land, not the state average

SSURGO maps about 27.4% of Maine as poorly or somewhat-poorly drained, and the class flips parcel to parcel. Turks Cap tolerates drought well, so wet feet — not dry spells — is its real risk here — your soil map unit, not the state average, is the real answer.

Check your parcel → Source: USDA NRCS SSURGO.

Plant pH and drainage requirements from USDA PLANTS Database. Maine soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.

Turks Cap in Maine — Quick Answer

  • Verdict: Conditional — Some Areas
  • Plant Zones: 7-11 (USDA PLANTS Database)
  • State Zones: 3b-7a (USDA ARS PHZM 2023)
  • Growing Season: 28°F hard freezes about Apr 16 - May 3 to Oct 10 - Oct 24 (NOAA Regional Climate Centers ACIS, 1991-2020)

What Else to Consider for Turks Cap 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

Growing turks cap here specifically

Turks Cap roots run deep and prefer pH 6.0–8.5, but drainage comes first here: SSURGO maps about 27.4% of Maine as poorly or somewhat-poorly drained, and wet ground rots its crown before pH ever matters.

Plant turks cap on a raised, gravel-amended berm so water drains fast and the crown stays dry. How to handle it →

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

Timing shifts within Maine

Maine isn't one climate. In Piscataquis County, the last hard freeze (28°F) holds until about May 15 — roughly 23 days later than the recorded state median — so plant turks cap to your county's window, not the statewide date.

Turks Cap needs about 365 days of frost-free season to complete its cycle. No Maine county gives it that outdoors: even Knox County, the state’s longest season at 222 frost-free days, falls 143 days short — so it needs transplants, a short-season variety, or covered growing.

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, which is 183 days short of what turks cap needs — so on a typical Maine parcel this is a transplant-or-protect crop, not a direct-sow one.

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"). Turks Cap's 365-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

Turks Cap draws hummingbirds and butterflies (high value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, turks cap 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.

Recommended Turks Cap Varieties for Maine

Maine publishes no state variety trial for turks cap, so we won't invent a "best for Maine" list. Choose types rated to your USDA hardiness zone (3b-7a), and confirm winter survival and drainage against your own parcel.

Maine Cooperative Extension

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

Common Questions About Growing Turks Cap in Maine

When can I plant Turks Cap 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). No sourced winter-hardiness floor is on record for Turks Cap, so this page does not state whether it overwinters in Maine and publishes no fall establishment date for it — check its hardiness range against your own zone before treating it as a permanent planting.

What hardiness zone is Turks Cap grown in across Maine?

Maine spans USDA hardiness zones 3b-7a (USDA ARS PHZM 2023). Turks Cap carries a range of zones 7-11, 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). Turks Cap needs 365+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date. In cooler counties like Piscataquis, the freeze-free season runs shorter than the state average, so verify your own county's window.

How should I amend the soil for Turks Cap in Maine?

Turks Cap prefers pH 6-8.5 and poorly (saturated >50% of year), well (dry spells) drainage (FAO ECOCROP). That sits in the common-ground band across Maine soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.

Will Turks Cap actually grow on my specific land in Maine?

State-level zone + climate data is a sketch. A Growable Ground parcel report scores turks cap 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 turks cap against your parcel's exact soil, sun, drainage, and frost data — not zone averages.

Three things about your lot that Maine turks cap 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 turks cap average

Analysis by the Growable Ground research team, grounded in USDA PLANTS, USDA NRCS SSURGO, NOAA Climate Normals (1991-2020), and named Cooperative Extension sources. How we know →

Cite this dataset

Kirchick, M. (2026). Growable Ground Plant Database [Data set]. Zenodo. https://doi.org/10.5281/zenodo.21435643

Licensed CC BY-NC 4.0. DOI 10.5281/zenodo.21435643

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