Generally — Most Areas
Ethiopian mustard (zones 4-10) suits most of Maine (3b-7a) — zones 4-7 are in range, and the rest of the state is the exception.
Your yard isn't the whole zone.
Ethiopian Mustard is grown as an annual, so your winter zone isn't the deciding factor — your frost-free window is. A typical Maine site runs ~182 frost-free days, but that is a state median, not your yard: slope, trees, and low spots move the last-frost date across a single parcel. Enter your address and we'll score ethiopian mustard against your land's actual frost dates, sun, and soil.
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Zone Comparison
Ethiopian Mustard Needs
- USDA Zones: 4-10
- Sun: Full Sun
- Mature size: 4 ft tall
- Drought tolerance: Medium
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 4-10)
Preferred Soil pH
Plant data: USDA PLANTS Database / Growable Ground plant catalog. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Ethiopian Mustard 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.
Frost tenderness
Ethiopian Mustard is frost-tender — its listed minimum temperature is 41°F (USDA PLANTS Database) — so set plants out two to three weeks PAST your local last hard freeze, not on it and not on the state's earliest date. The 28°F marker above is when killing freezes stop, not when light frost does.
When to start the seed
Ethiopian Mustard is direct-sown where it grows rather than started under cover, so there is no seed-tray head start to bank — Maine's dates above are the whole calendar for it. That makes the last-freeze date the binding constraint, and a warmer pocket of your own yard is worth more to this crop than it is to a transplanted one.
Days to maturity vs. the window
At 90 days to maturity (USDA PLANTS Database), counting from the last hard freeze it ripens with 70 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: 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 ethiopian mustard survives winter in part of Maine, not across all of it. Whether the season is long enough — and warm enough — is a different question.
Days to maturity
Ethiopian Mustard matures in ~90 days (Growable Ground Plant Database). A typical Maine site has ~182 frost-free days, so plenty of room for a second succession.
Growing degree days
Ethiopian Mustard needs ~1400 GDD (base 50°F) to ripen. The state median runs ~1450 GDD (from PRISM 1991-2020 climate normals), so Maine sits right at the threshold — pay attention to siting and microclimate.
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
Ethiopian Mustard 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 8 — 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 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.
Ethiopian Mustard in Maine — Quick Answer
- Verdict: Generally — Most Areas
- Plant Zones: 4-10 (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)
- Days to Maturity: 90 days
What Else to Consider for Ethiopian Mustard 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 ethiopian mustard — is covered on the Maine growing guide.
Timing shifts within Maine
Ethiopian Mustard needs about 90 days of frost-free season from planting to harvest. Even Franklin County — Maine’s shortest season at 143 frost-free days — clears that by 53 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 ethiopian mustard about 92 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"). Ethiopian Mustard's 90-day requirement: USDA PLANTS / Growable Ground plant database (days to maturity). A parcel report resolves your address's own frost dates.
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 ethiopian mustard (USDA PHZM 2023):
Pollinator + Wildlife Value
Ethiopian Mustard draws honeybees and native bees (moderate value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, ethiopian mustard 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 ethiopian mustard, the canonical source is UMaine Cooperative Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Ethiopian Mustard native to Maine?
No — the USDA PLANTS Database lists Ethiopian Mustard 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.
Common Questions About Growing Ethiopian Mustard in Maine
When can I plant Ethiopian Mustard 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). Ethiopian Mustard is frost-tender — its listed minimum temperature is 41°F (USDA PLANTS Database) — so wait two to three weeks past your site's last hard freeze, when light frost has also stopped, before planting out.
Can Ethiopian Mustard mature before first frost in Maine?
Yes — Ethiopian Mustard matures in 90 days (USDA PLANTS Database), and Maine's dependable hard-freeze-free window runs 160 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 70 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 Ethiopian Mustard grown in across Maine?
Maine spans USDA hardiness zones 3b-7a (USDA ARS PHZM 2023). Ethiopian Mustard carries a range of zones 4-10, 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). Ethiopian Mustard should be matched against that window, so check whether your local microclimate runs above or below the state average before settling on a planting date.
Is Ethiopian Mustard native to Maine?
No — the USDA PLANTS Database lists Ethiopian Mustard 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 Ethiopian Mustard in Maine?
Ethiopian Mustard 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 Ethiopian Mustard actually grow on my specific land in Maine?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores ethiopian mustard against your address's exact soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.
Check your specific parcel in Maine
State-level data is a sketch. Your Growable Ground report scores ethiopian mustard against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Maine ethiopian mustard averages can't show:
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