Yes — Strong Match
peppermint is grown in zones 3-11, which covers every zone Washington contains (4a-9b). Whether the season is long enough is the question that remains.
Peppermint in Washington — the short answer
Peppermint in Washington: grown in zones 3–11, full sun.
- Plant zones
- 3-11
- Not verified — NC State Extension Gardener Plant Toolbox lists zones 5a–9b
- Washington zones
- 4a-9b
- USDA PHZM 2023
- Frost window
- Mar 16 - Apr 15 – Oct 24 - Nov 18
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 131 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
- Days to maturity
- 90 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.
Your yard isn't the whole zone.
Washington spans zones 4a-9b, 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 peppermint 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
Washington is not one climate
A single Washington answer averages 39 counties whose growing seasons are 169 days apart — from 131 frost-free days in Whatcom County to 300 in San Juan County. Which end of that your land sits nearer changes what peppermint can finish before the first hard freeze.
The middle half of 39 counties runs 192–248 days, with a median of 208 days — a 169-day span end to end.
Measured across 39 Washington 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 Washington Fits Best
Even within Washington's zones 4a-9b, county microclimates differ enough to change what thrives. These counties carry the closest zone match for peppermint (USDA PHZM 2023):
Zone Comparison
Peppermint Needs
- USDA Zones: 3-11
- Sun: Full Sun
- Mature size: 2 ft tallWe haven't confirmed this against a published source yet.
- Picking window: ~150 days of harvestWe haven't confirmed this against a published source yet.
- Drought tolerance: LowWe haven't confirmed this against a published source yet.
Washington Has
- USDA Zones: 4a-9b
- Last Hard Freeze (28°F): Mar 16 - Apr 15
- First Hard Freeze (28°F): Oct 24 - Nov 18
- Annual Rainfall: 6-90 inches
- Common Soils: Volcanic ash, Silt loam (Palouse), Sandy loam
Plant Zone Range (zones 3-11)
Preferred Soil pH
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 Peppermint in Washington
The frost window
Across Washington, the last spring hard freeze (28°F) clears between Mar 16 and Apr 15, and the first fall hard freeze lands between Oct 24 and Nov 18 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 192-day window you can count on — up to 247 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
Washington runs as cold as USDA zone 4, and no sourced winter-hardiness floor is on record for peppermint, so this page does not state whether it overwinters here — and gives no fall establishment date on the strength of a guess. Whether peppermint is a permanent planting or a replant-every-spring crop for you turns on your own zone within Washington; check its hardiness range against that before treating it as long-lived ground.
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
Peppermint is grown in zones 3–11, which covers every zone Washington contains (4a-9b). We have no sourced winter-survival figure for peppermint, so this page does not say whether it overwinters here. Washington's typical season runs ~208 frost-free days against the ~40 peppermint needs.
Growing degree days
Peppermint needs ~900 GDD (base 50°F) to ripen. We haven't confirmed this against a published source yet. The state median runs ~1740 GDD (from PRISM 1991-2020 climate normals), so Washington's typical season clears that easily.
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
Peppermint tolerates a wide pH range (pH 4.5-8.3) — 3.8 units, acid ground through alkaline — so soil acidity is rarely what limits it in Washington. 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 6.5 — worth knowing before you decide whether a Washington soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Washington site is heavier clay or sits in a low spot, a raised bed lifts the roots above wet ground, or work in compost. Drainage need: We haven't confirmed this against a published source yet.
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. Washington soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Before you plant peppermint 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 peppermint goes in. What follows is Washington’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 Washington — and how to grow with it.
We checked the federal record across Washington — 22,904 documented sites across 7 of the 8 source types we track.
The most significant on record: 329 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Washington 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.
Sources Checked
across Washington
Severity Distribution
across Washington
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Washington, Mining runs higher than the national average — 3,881 sites across Washington. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Sources: EPA, USGS — 950K documented sites tracked nationwide across 8 federal source types.
What Else to Consider for Peppermint in Washington
The zone range tells you where peppermint is grown — but Washington growers also need to think about:
Extreme rain divide: 90+ inches west, 6 inches east of Cascades
East side requires irrigation — no rain from June through September
Slug and root rot pressure on the wet west side
Short seasons at elevation in the Cascades and northeast corners
What to actually do about these — and the constraints that apply to every Washington grower, not just peppermint — is covered on the Washington growing guide.
Where in Washington Peppermint Is Zone-Hardy
Peppermint is rated for USDA zones 3–11. Every one of Washington’s 39 counties sits inside that band — from Ferry County at zone 6a to San Juan County at zone 9a — so winter cold is not what decides this plant anywhere in the state. What is left to vary is your own parcel: slope, shelter and cold-air drainage routinely move a site half a zone either way from the county figure.
Across those 39 counties Washington’s winter-low ladder runs from zone 6a in Ferry County to zone 9a in San Juan County — 3 USDA zones of spread, which is 30°F between the two counties’ average coldest night of the year. That is why a statewide hardiness answer is where you start and not where you finish.
The planting window moves with it. Whatcom County holds its last hard freeze (28°F) until about May 29, while Island County is clear by Feb 8 — 110 days apart. Set peppermint out on your county’s date, not the state’s.
County hardiness zones: USDA Plant Hardiness Zone Map (PHZM) 2023, per county. County last-freeze dates: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F killing freeze — earlier than the folk 32°F "last frost". Peppermint’s zone 3–11 band: Not verified — NC State Extension Gardener Plant Toolbox lists zones 5a–9b. A parcel report resolves your address’s own zone and frost dates rather than its county’s.
Pollinator + Wildlife Value
Peppermint draws honeybees, native bees, and butterflies (moderate value). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, peppermint can only work that bloom inside Washington's frost window — roughly 208 days, opening after the last 28°F freeze (Mar 16 - Apr 15) and closing at the first (Oct 24 - Nov 18), per NOAA Regional Climate Centers ACIS, 1991-2020. Pollinator value: We haven't confirmed this against a published source yet.
Washington Cooperative Extension
For Washington-specific cultivar recommendations, planting calendars, and pest pressure for peppermint, the canonical source is WSU Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Common Questions About Growing Peppermint in Washington
When can I plant Peppermint in Washington?
Washington's last spring hard freeze (28°F) clears between Mar 16 and Apr 15, and the first fall hard freeze lands between Oct 24 and Nov 18 (NOAA Regional Climate Centers ACIS, 1991-2020). No sourced winter-hardiness floor is on record for Peppermint, so this page does not state whether it overwinters in Washington 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 Peppermint grown in across Washington?
Washington spans USDA hardiness zones 4a-9b (USDA ARS PHZM 2023). Peppermint carries a range of zones 3-11, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Washington site have?
A typical Washington site sees ~208 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Peppermint needs 40+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date.
How should I amend the soil for Peppermint in Washington?
Peppermint tolerates pH 4.5-8.3 and well (dry spells) drainage. We haven't confirmed this against a published source yet. That is a 3.8-unit span, acid ground through alkaline, so pH is rarely what limits this plant on a Washington site — amend for drainage and organic matter first.
Will Peppermint actually grow on my specific land in Washington?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores peppermint against your address's mapped soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.
Check your specific parcel in Washington
State-level data is a sketch. Your Growable Ground report scores peppermint against your land's mapped soil, modelled sun, drainage, and frost data — not zone averages.
Three things about your lot that Washington peppermint averages can't show:
We read public map data around Washington — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Washington peppermint average
Explore More
Growing guides for peppermint
Explore Washington county by county
Washington carries 39 counties with their own USDA zone — a sample of the growing pages for peppermint there:
Where else peppermint grows
Peppermint's zone band crosses state lines — these are the states closest to Washington in winter climate where it also has a page, plus the far ends of its range. Each one re-answers the question with that state's own record.
More to grow in Washington
Washington has a growing page for 1,033 plants — a rotating sample of the rest of the shelf.
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