Yes — Strong Match
mache is grown as an annual, so season length decides it here, not a winter zone — and Oregon's typical season runs ~213 frost-free days against the ~45 mache needs.
Sow by about Sep 17
Mache is grown as an annual, so what decides it here is season length, not a winter zone. It needs about 45 frost-free days and a typical Oregon season runs ~213 frost-free days, leaving 168 days of slack. That is room to sow as late as about Sep 17 and still finish before the usual first freeze (Nov 6), or to run a second succession.
Want more weeks at either end of that window? How to buy the weeks →
45 frost-free days required against Oregon’s ~213-day season. NOAA Regional Climate Centers ACIS 1991-2020 (28°F killing freeze), state median across counties, via stateClimateData.ts.
Your yard isn't the whole zone.
Mache is grown as an annual, so your winter zone isn't the deciding factor — your frost-free window is. A typical Oregon site runs ~213 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 mache against your land's actual frost dates, sun, and soil.
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Zone Comparison
Mache Needs
- USDA Zones: Data pending
- Frost-Free Days: 45+
- Sun: Full Sun
- Mature size: 6 in tall
- Picking window: ~21 days of harvest
- Drought tolerance: Low
Oregon Has
- USDA Zones: 5a-10a
- Last Hard Freeze (28°F): Feb 25 - Apr 26
- First Hard Freeze (28°F): Oct 19 - Nov 26
- Annual Rainfall: 8-90 inches
- Common Soils: Volcanic, Silt loam (Willamette), Sandy loam
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 Mache in Oregon
The frost window
Across Oregon, the last spring hard freeze (28°F) clears between Feb 25 and Apr 26, and the first fall hard freeze lands between Oct 19 and Nov 26 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 176-day window you can count on — up to 274 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
Mache is direct-sown where it grows rather than started under cover, so there is no seed-tray head start to bank — Oregon'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 50 days to maturity (USDA PLANTS Database), counting from the last hard freeze it ripens with 126 days to spare even in Oregon's tightest freeze scenario — room for a later start or a second sowing.
Timing tuned to sub-state frost dates — Klamath 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
Frost-free days
Mache wants 45+ frost-free days; a typical Oregon site sees ~213 (NOAA Regional Climate Centers ACIS, 1991-2020). That leaves comfortable headroom for succession planting.
Growing degree days
Mache needs ~600 GDD (base 50°F) to ripen. The state median runs ~1666 GDD (from PRISM 1991-2020 climate normals), so Oregon'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
Mache likes near-neutral soil (pH 6-7.5). That's the common-ground band across Oregon's volcanic and silt loam (willamette) — a soil test confirms it for your site. It will grow across that whole span, but it does best between pH 6.5 and 7 — worth knowing before you decide whether a Oregon soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Oregon site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Your land, not the state average
Whether mache is safe to eat from Oregon soil is a block-by-block question, not a town-wide one — 21,752 documented contamination sites mean levels spike on some parcels and not the one next door. What mache takes up depends on the horizon its roots actually reach on your parcel, so only a test on your address settles it.
Check your parcel → Source: USDA NRCS SSURGO + EPA/state contamination databases.
Plant pH and drainage requirements from USDA PLANTS Database. Oregon soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
Mache in Oregon — Quick Answer
- Verdict: Yes — Strong Match
- Plant Zones: Data pending (USDA PLANTS Database)
- State Zones: 5a-10a (USDA ARS PHZM 2023)
- Growing Season: 28°F hard freezes about Feb 25 - Apr 26 to Oct 19 - Nov 26 (NOAA Regional Climate Centers ACIS, 1991-2020)
- Days to Maturity: 50 days
What Else to Consider for Mache in Oregon
Zone compatibility tells you about winter cold survival — but Oregon growers also need to think about:
West side: excessive rain and overcast skies reduce sun for warm-season crops
East side: arid conditions (8-15 inches rainfall) require irrigation
Slug pressure is extreme in western Oregon
Mountain areas have very short seasons (60-90 frost-free days)
Growing mache here specifically
Because you eat the leaves of mache that sit in the soil, contamination matters more than for most crops — Oregon has 21,752 documented sites, and lead concentrates block by block, not town-wide.
Test your soil for lead first, and raise mache in clean imported soil if the reading is high. How to handle it →
What to actually do about these — and the constraints that apply to every Oregon grower, not just mache — is covered on the Oregon growing guide.
Timing shifts within Oregon
Oregon isn't one climate. In Klamath County, the last hard freeze (28°F) holds until about Jun 9 — roughly 67 days later than the recorded state median — so plant mache to your county's window, not the statewide date.
Mache needs about 45 days of frost-free season to complete its cycle. Even Klamath County — Oregon’s shortest season at 86 frost-free days — clears that by 41 days, so season length isn’t the constraint anywhere in Oregon. What varies is your own parcel.
Across Oregon’s 36 counties the frost-free season runs from 86 days in Klamath County to 308 days in Lincoln County — a spread of 222 days, which is why a single statewide planting date misleads. The median Oregon county sees 213 frost-free days, leaving mache about 168 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"). Mache's 45-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
Mache draws honeybees (low value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, mache can only work that bloom inside Oregon's frost window — roughly 213 days, opening after the last 28°F freeze (Feb 25 - Apr 26) and closing at the first (Oct 19 - Nov 26), per NOAA Regional Climate Centers ACIS, 1991-2020.
Oregon Cooperative Extension
For Oregon-specific cultivar recommendations, planting calendars, and pest pressure for mache, the canonical source is OSU Extension Service. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Mache native to Oregon?
No — the USDA PLANTS Database lists Mache as introduced rather than native in the Lower 48, so it is not part of Oregon's native flora. It grows here as a garden plant; pairing it with a few Oregon natives keeps local pollinators fed too.
Looking for plants that belong here? The Oregon 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 Mache in Oregon
When can I plant Mache in Oregon?
Oregon's last spring hard freeze (28°F) clears between Feb 25 and Apr 26, and the first fall hard freeze lands between Oct 19 and Nov 26 (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 Mache mature before first frost in Oregon?
Yes — Mache matures in 50 days (USDA PLANTS Database), and Oregon's dependable hard-freeze-free window runs 176 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 126 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 Mache grown in across Oregon?
Oregon spans USDA hardiness zones 5a-10a (USDA ARS PHZM 2023). Mache carries a range of zones Data pending, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Oregon site have?
A typical Oregon site sees ~213 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Mache needs 45+ 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 Klamath, the freeze-free season runs shorter than the state average, so verify your own county's window.
Is Mache native to Oregon?
No — the USDA PLANTS Database lists Mache as introduced rather than native in the Lower 48, so it is not part of Oregon's native flora. It grows here as a garden plant; pairing it with a few Oregon natives keeps local pollinators fed too.
How should I amend the soil for Mache in Oregon?
Mache prefers pH 6-7.5 and well (dry spells) drainage (Growable Ground Plant Database). That sits in the common-ground band across Oregon soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Mache actually grow on my specific land in Oregon?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores mache 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 Oregon
State-level data is a sketch. Your Growable Ground report scores mache against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Oregon mache averages can't show:
We read public map data around Oregon — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Oregon mache average
Explore More
Growing guides for mache
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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