Yes — Strong Match
phacelia (zones 2-11) covers every zone Oregon contains (5a-10a), so hardiness is not what limits it anywhere in the state.
Phacelia in Oregon — the short answer
Phacelia in Oregon: hardy in zones 2–11, full sun, against a state median of ~213 frost-free days.
- Plant zones
- 2-11
- Manual horticultural correction (source not retained); NC State Extension and Missouri Botanical Garden, with the remaining rows from other published sources or Growable Ground compilation
- Oregon zones
- 5a-10a
- USDA PHZM 2023
- Frost window
- Feb 25 - Apr 26 – Oct 19 - Nov 26
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 86 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
- Days to maturity
- 45 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.
Phacelia 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 phacelia against your land's actual frost dates, sun, and soil.
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Oregon is not one climate
A single Oregon answer averages 36 counties whose growing seasons are 222 days apart — from 86 frost-free days in Klamath County to 308 in Lincoln County. Which end of that your land sits nearer changes what phacelia can finish before the first hard freeze.
The middle half of 36 counties runs 165–274 days, with a median of 212 days — a 222-day span end to end.
Measured across 36 Oregon 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 Oregon Fits Best
Even within Oregon's zones 5a-10a, county microclimates differ enough to change what thrives. These counties carry the closest zone match for phacelia (USDA PHZM 2023):
Zone Comparison
Phacelia Needs
- USDA Zones: 2-11
- Frost-Free Days: 100+
- Sun: Full Sun
- Mature size: 3 ft tall
- Picking window: ~30 days of harvest
- Drought tolerance: Medium
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
Plant Zone Range (zones 2-11)
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 Phacelia 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.
Frost hardiness
Phacelia takes cold down to about 18°F before a freeze kills it (FAO ECOCROP), so you can plant on the early side of Oregon's window — even a few weeks before the final hard freeze. That is the point where cold damages growing tissue, not a winter-survival floor — an established perennial comes through far colder while dormant, which is what its hardiness zone tells you.
When to start the seed
Phacelia 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 45 days to maturity (Growable Ground Plant Database), counting from the last hard freeze it ripens with 131 days to spare even in Oregon's tightest freeze scenario — room for a later start or a second sowing.
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
The zone check says phacelia survives winter here. Whether the season is long enough — and warm enough — is a different question.
Frost-free days
Phacelia wants 100+ 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
Phacelia needs ~1000 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
Phacelia likes near-neutral soil (pH 6.4-8.6). 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 and 7.5 — 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.
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. Oregon soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
What Else to Consider for Phacelia 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)
What to actually do about these — and the constraints that apply to every Oregon grower, not just phacelia — is covered on the Oregon growing guide.
Timing shifts within Oregon
Phacelia needs about 100 days of frost-free season to complete its cycle. 35 of Oregon’s 36 counties give it that outright. The tightest that does is Lake County at 134 frost-free days — 34 to spare. Below that line you are transplanting or extending the season, not direct-sowing.
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 phacelia about 113 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"). Phacelia's 100-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
Phacelia draws honeybees, native bees, and butterflies (high value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, phacelia 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 phacelia, the canonical source is OSU Extension Service. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Phacelia native to Oregon?
Yes — the USDA PLANTS Database (accessed 2026-07-01) documents Phacelia as native to Oregon. Planting it supports the pollinators and wildlife that evolved alongside it.
Native-range data: USDA PLANTS Database state-distribution records, accessed 2026-07-01.
Common Questions About Growing Phacelia in Oregon
When can I plant Phacelia 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). Phacelia takes cold to about 18°F before a freeze kills it (FAO ECOCROP — the point where cold damages growing tissue, not a winter-survival floor), so plant on the early side of that window — even ahead of the final hard freeze.
Can Phacelia mature before first frost in Oregon?
Yes — Phacelia matures in 45 days (Growable Ground Plant Database), and Oregon's dependable hard-freeze-free window runs 176 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 131 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 Phacelia grown in across Oregon?
Oregon spans USDA hardiness zones 5a-10a (USDA ARS PHZM 2023). Phacelia carries a range of zones 2-11, 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). Phacelia needs 100+ frost-free days, so check whether your local microclimate runs above or below the state average before settling on a planting date.
Is Phacelia native to Oregon?
Yes — the USDA PLANTS Database (accessed 2026-07-01) documents Phacelia as native to Oregon. Planting it supports the pollinators and wildlife that evolved alongside it.
How should I amend the soil for Phacelia in Oregon?
Phacelia prefers pH 6.4-8.6 and well (dry spells) drainage (USDA PLANTS). 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 Phacelia actually grow on my specific land in Oregon?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores phacelia 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 phacelia against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Oregon phacelia 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 phacelia average
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