purple nut grass (Cyperus rotundus), photographi

Can I Grow Purple Nut Grass in Maine?

USDA Zones 3b-7a · Plant zone range 8-12

Unlikely — Zone Mismatch

purple nut grass (zones 8-12) does not overlap with Maine's zone range (3b-7a). Growing outdoors is unlikely without significant protection.

2 zones short — what would close it

Purple Nut Grass is hardy to zone 8, and the warmest ground in Maine is zone 6 — 2 zones short. Planted in open ground it will not survive a Maine winter. To grow it here, grow purple nut grass in an earth-sheltered greenhouse — its modeled 2.5-zone lift covers this gap.

An earth-sheltered greenhouse is the lift this needs. How a greenhouse changes what you can grow →

Zone math from 8-12 (plant) against 3-6 (Maine). Lift modeled by crop_engine.GREENHOUSE_ZONE_MODIFIER_BY_SUBTYPE['earth_sheltered'] (+2.5 zones) via api/fast_sections.py Unlock Engine v2.

Purple Nut Grass in Maine — the short answer

Purple Nut Grass in Maine: hardy in zones 8–12, full sun.

Plant zones
8-12
Not verified — NC State Extension Gardener Plant Toolbox lists zones 3a–10b
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

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 to start

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 purple nut grass against your parcel's actual hardiness, soil, and sun.

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

No card required · your parcel report in seconds — read in full free for your first 14 days

Maine is not one climate

Maine’s winter-low ladder runs across 16 counties, from zone 4 in Aroostook County to zone 6 in Lincoln County. That is 20°F between the two counties’ average coldest night — the difference between purple nut grass overwintering in the ground and coming under cover.

4 zonesAroostook County6 zonesLincoln County

The middle half of 16 counties runs 4.5–5.5 zones, with a median of 5.5 zones — a 2-zone span end to end.

Measured across 16 Maine counties. USDA PHZM 2023, per county. 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 Purple Nut Grass Stands in Maine

Purple Nut Grass is rated for zones 8–12 — a cold floor USDA puts at 10 to 20°F. No Maine county sits inside it, so in open ground this is a grown-under-cover plant here rather than a bed plant — which is a statement about Maine winters, not about purple nut grass.

Below the zone 8 floor

16 counties

3 of 16 shown

Winter cold is the limit here — the same plant works in a container that comes under cover.

County hardiness zones: USDA Plant Hardiness Zone Map (PHZM) 2023, per county. A zone is a 10°F band of average annual extreme minimum temperature, so the floor above is the band the plant's rating denotes, not a single measured kill point. Slope, shelter and cold-air drainage routinely move a site half a zone either way from its county figure — which is the part only your address resolves.

Zone Comparison

Purple Nut Grass Needs

  • USDA Zones: 8-12
  • Sun: Full Sun
  • Picking window: ~120 days of harvestWe haven't confirmed this against a published source yet.

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 8-12)

8a
12b
3a (Cold)13b (Hot)

Preferred Soil pH

3.5 (Acidic)7.0 (Neutral)9.0 (Alkaline)
Highlighted range: pH 3.5 – 8.0

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 Purple Nut Grass 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 purple nut grass, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether purple nut grass 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: 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.

Soil + Drainage Fit

Purple Nut Grass tolerates a wide pH range (pH 3.5-8) — 4.5 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 — 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, a raised bed lifts the roots above wet ground, or work in compost.

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. Purple Nut Grass sits mid-range for drought tolerance, so either extreme can cost you — your soil map unit, not the state average, is the real answer.

Check your parcel → Source: USDA NRCS SSURGO.

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 purple nut grass 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 purple nut grass 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 Maine — 7,879 documented sites across 7 of the 8 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 of imported, lab-tested soil grow well almost anywhere in the meantime.

Know before you grow — the guide

Sources Checked

across Maine

Severity Distribution

across Maine

High163Moderate2,021Low5,695

Highest-Severity Sites

Mining Sites · Past Producer
Mining Sites · Past Producer
Mining Sites · Past Producer
PFAS Sampling · PFAS Detected
Superfund · Superfund NPL

A note from Gnorman

What an experienced grower watches for around here

In and around Maine, Brownfields runs higher than the national average — 961 sites across Maine. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.

Brownfields: Brownfield sites are former commercial or industrial properties that EPA’s Brownfields program (ACRES) has assessed or funded cleanup on.

Contact the EPA Brownfields program or the state cleanup agency for this site’s actual assessment/remediation status — ACRES itself does not publish one we can read per site.

Sources: EPA, USGS — 950K documented sites tracked nationwide across 8 federal source types.

What Else to Consider for Purple Nut Grass 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 purple nut grass here specifically

Purple Nut Grass likes pH 3.5–8.0 and its growing tissue burns around 32°F (FAO ECOCROP), yet neither saves it from wet feet — SSURGO maps about 27.4% of Maine poorly-drained, where its crown sit and rot.

Set purple nut grass high on bermed, grit-amended ground so winter and storm water drain away from the crown. How to handle it →

What to actually do about these — and the constraints that apply to every Maine grower, not just purple nut grass — 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 purple nut grass to your county's window, not the statewide date.

County last-freeze dates: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F freeze (earlier than the folk 32°F "last frost"). A parcel report resolves your address's own frost dates.

Where in Maine Purple Nut Grass Is Zone-Hardy

Purple Nut Grass is rated for USDA zones 8–12. No Maine county reaches it. Even Lincoln County, the state’s mildest winter at zone 6a, sits below the plant’s zone 8 floor — so in open ground this one needs winter protection here, or a container that comes under cover.

Across those 16 counties Maine’s winter-low ladder runs from zone 4a in Aroostook County to zone 6a in Lincoln County — 2 USDA zones of spread, which is 20°F between the two counties’ average coldest night of the year. None of that range reaches the band purple nut grass needs, so here the statewide answer really is the answer.

County hardiness zones: USDA Plant Hardiness Zone Map (PHZM) 2023, per county. Purple Nut Grass’s zone 8–12 band: Not verified — NC State Extension Gardener Plant Toolbox lists zones 3a–10b. A parcel report resolves your address’s own zone and frost dates rather than its county’s.

Recommended Purple Nut Grass Varieties for Maine

Maine publishes no state variety trial for purple nut grass, 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 purple nut grass, the canonical source is UMaine Cooperative Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.

Is Purple Nut Grass native to Maine?

No — the USDA PLANTS Database lists Purple Nut Grass 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 plants that USDA PLANTS records growing in Maine and that Kew and NatureServe Explorer both list in its native range, leaving out any that NatureServe flags as exotic there or that our audit holds.

State records: USDA PLANTS Database state-distribution data (presence, not state-level nativity), accessed 2026-10-19.

Common Questions About Growing Purple Nut Grass in Maine

When can I plant Purple Nut Grass 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 Purple Nut Grass, 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 Purple Nut Grass grown in across Maine?

Maine spans USDA hardiness zones 3b-7a (USDA ARS PHZM 2023). Purple Nut Grass is listed for zones 8-12, which do not overlap them, so there is no zone in Maine where this page can call outdoor growing reliable. A parcel report resolves your own address's zone.

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). Purple Nut Grass needs 120+ 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.

Is Purple Nut Grass native to Maine?

No — the USDA PLANTS Database lists Purple Nut Grass 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 Purple Nut Grass in Maine?

Purple Nut Grass tolerates pH 3.5-8 and poorly (saturated >50% of year), well (dry spells) drainage (FAO ECOCROP). That is a 4.5-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 Purple Nut Grass actually grow on my specific land in Maine?

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

Free to start

Check your specific parcel in Maine

State-level data is a sketch. Your Growable Ground report scores purple nut grass against your land's mapped soil, modelled sun, drainage, and frost data — not zone averages.

Three things about your lot that Maine purple nut grass 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 purple nut grass 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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