The Pacific Northwest spans USDA hardiness zones 7a-10a — a zone band wide enough that plant choice, not possibility, is the interesting question.
The maritime Northwest west of the Cascade crest — mild, wet winters and dry summers behind berries, tree fruit, and lush cool-season gardens. (Union of the west-side ecoregions.) Expect tomato, kale, potato, and fig to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
The Pacific Northwest spans California, Oregon and Washington. Its footprint follows the EPA Level III ecoregion boundary; the counties linked below are representative of the region, not an exhaustive list.
Your yard isn't all of the Pacific Northwest.
The Pacific Northwest spans USDA zones 7a-10a, but your parcel sits in exactly one — and slope, tree cover, and low spots nudge it further. Enter your address and we'll score 1,086 plants against your land's actual soil, sun, and frost.
We read public map data around Pacific Northwest — soil, climate, flood, and parcel records. How we handle your address.
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The Pacific Northwest — the short answer
The Pacific Northwest: USDA zones 7a-10a, 131–365 frost-free days depending where in it you stand, across 3 states.
- USDA zones
- 7a-10a
- USDA PHZM 2023, aggregated over the footprint
- Shortest season here
- 131 days
- NOAA Regional Climate Centers ACIS, 1991-2020 — Whatcom County
- Counties
- 39
- US Census TIGER/Line 2025
- Region type
- EPA ecoregion
- Growable Ground growing-region registry
Region boundary: Growable Ground growing-region registry — curated county clusters, EPA Level III ecoregions, and town clusters drawn finer than any county. The season figure is this region's own record, measured across its 39 member counties, not a state or national average.
Hardiness Zone Range
The Pacific Northwest is not one growing season
One answer for the Pacific Northwest averages 39 counties whose growing seasons are 234 days apart — from 131 frost-free days in Whatcom County to 365 in San Mateo County. That is the same region, measured the same way, in the same years. Which end of it your land sits nearer decides what finishes before the first hard freeze.
The middle half of 39 counties runs 243–287 days, with a median of 256 days — a 234-day span end to end.
Measured across 39 member counties, each carrying its own 28°F normal. NOAA Regional Climate Centers ACIS, 1991-2020. A member with no own record is absent from the range rather than counted as zero — nothing here is interpolated to the region. Your own site sits somewhere inside this range; a parcel report resolves where.
Where the line runs inside the Pacific Northwest
The middle half of the Pacific Northwest runs 243–287 frost-free days, and 20 of its 39 counties sit outside that — 10 on the short side, 10 on the long. A regional planting date describes the middle well and the ends poorly, which is worth knowing before you follow one.
Under 243 frost-free days
10 counties
- Whatcom County · 131 days
- Chelan County · 158 days
- Jefferson County · 187 days
3 of 10 shown
The end of the region that sets the planting calendar — start seed indoors here and the season stretches to meet the crop.
243–287 frost-free days
19 counties
0 of 19 shown
The middle half of the region, and the part a single regional season describes well.
Over 287 frost-free days
10 counties
- San Mateo County · 365 days
- Santa Cruz County · 333 days
- Lincoln County · 308 days
3 of 10 shown
Long enough for a second succession of a quick crop after the first comes out.
Each county is placed by its OWN 28°F frost-free normal (NOAA Regional Climate Centers ACIS, 1991-2020), the same figure its own guide page publishes. Elevation, slope and cold-air drainage move a site within its county as well — which is the part only your address resolves.
What Grows in the Pacific Northwest
All 1 of the plants below that publish a season requirement clear even Whatcom County’s 131 frost-free days — so on season alone, this grid works at both ends of the region. The 234-day spread still decides how far past this list you can push, and how early you can start.
Plants matched to the Pacific Northwest's USDA zones 7a-10a, ordered by how much hardiness margin each has across the region — the ones with room to spare at both ends of this band lead. Each links to its full growing profile.
Native Plants of the Pacific Northwest
Plants the USDA PLANTS Database documents as native and present in all 3 states this region crosses, kept only where the published hardiness range meets the Pacific Northwest’s USDA zones 7a-10a — closest range match first. Presence is recorded by state, so a plant can be documented across the state and still be scarce in your corner of the region.
The ground across the Pacific Northwest
The USDA soil survey maps this ground county by county. These are those records weighted by land area across 39 member counties — this region’s own profile, not a state figure.
The ground is predominantly Inceptisols, at 33% of mapped acres, followed by Andisols (24%), Mollisols (12%) and Ultisols (11%). Eleven soil orders appear somewhere inside the footprint, which is the honest reason a regional soil answer only goes so far. The most extensive named soils are Alderwood, Bohannon, and Preacher.
65% of those acres are well drained, and another 15% moderately well drained, 5% somewhat excessively drained. Topsoil pH runs 4.6–7.0 between the lowest and the highest county on record. 8% of the footprint is classed prime farmland.
Soil order
Inceptisols
Drainage
Well drained
Topsoil pH
4.6–7.0
Hydric soils
6%
Soil changes across a driveway, so which of these your own ground sits on is a parcel question rather than a regional one. Linn County holds the most wetland ground here, at 16% — soil types explained.
USDA NRCS SSURGO via Soil Data Access
What this means for growing in the Pacific Northwest
The soil survey reads this ground county by county, and the readings above are those records summed across the Pacific Northwest. Here is what they mean for a garden here — and the move an experienced grower makes about each one.
Drainage
From county records65% of the mapped acres across the Pacific Northwest are well drained — ground that drains quickly. That is area-weighted across all 39 of its mapped counties.
The upside is soil you can work early in spring and roots that never drown; the cost is that fast-draining ground dries out fast and leaches nutrients away before plants can use them.
Work in compost and mulch to hold moisture and feed, and water more often in short doses than deep and rarely.
USDA NRCS SSURGO
Surface pH
From county recordsTopsoil across the Pacific Northwest runs pH 4.6–7.0 — acidic in 34 of its 39 counties.
Blueberries, potatoes, and rhododendrons thrive in it, but most vegetables start locking out nutrients below about pH 6.0 and grow pale and stunted no matter how much you feed them.
A measured lime application raises pH for the crops that need it — but test first, because the right rate depends on your own soil, not the county average.
USDA NRCS SSURGO
Safe to Grow Here?
What the federal record shows across the Pacific Northwest — and how to grow with it.
Across the Pacific Northwest's 39 counties the federal record holds 43,366 documented sites, mostly Underground Storage Tanks (19,196), Brownfields (14,841) and Nitrate (4,648). The heaviest single county is King County, with 6,301.
That is a regional count, not a reading of any one lot — proximity to a documented site is information, not a diagnosis. Open the map outlined to the Pacific Northwest to see which records sit where you actually grow.
Sources Checked
Summed across the 39 counties in the Pacific Northwest
Know Before You Grow
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •Near a brownfield, raised beds of imported soil give your food clean ground.
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
Your land is one point inside the Pacific Northwest
Everything above resolves to the Pacific Northwest as a whole — a footprint whose own counties record seasons 234 days apart, and hardiness across zones 7a-10a. Your parcel sits at one point in that range, not in the middle of it. Slope, tree cover, a low spot that pools cold air, and what is in the soil are all resolved at the address, and none of them are visible at region scale. That is the honest boundary of this page, and the reason the next step is a reading of your own ground rather than a better regional average.
Your Lot vs the Pacific Northwest Average
Pacific Northwest Average
- ●USDA Zones 7a-10a, averaged across Pacific Northwest
- ●One soil character for all of Pacific Northwest
- ●State-average frost dates
YOUR Parcel
- ✓Your exact zone, not Pacific Northwest's 7a-10a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in the Pacific Northwest
Pull a site-specific report for your exact address in the Pacific Northwest — soil, sun, drainage, frost risk, contamination, and scored plant recommendations.
Three things about your lot that Pacific Northwest averages can't show:
We read public map data around The Pacific Northwest — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Pacific Northwest average
How we know this about the Pacific Northwest
The boundary: an EPA Level III ecoregion (an area sharing climate, soils, and vegetation). Growing regions have no official boundary, so this footprint is our published one, and every figure on this page was measured over the counties inside it rather than borrowed from the state around it.
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, aggregated across the footprint; the growing season from NOAA Regional Climate Centers ACIS 1991–2020 28°F normals, read at each member’s own record; boundaries from US Census TIGER/Line 2025; the contamination record from the federal sources named in that beat above; the soil from the USDA NRCS SSURGO survey, read at each member county’s own record and weighted to this footprint by land area. Where a member carries no record of its own, it is absent from the figure rather than filled in.
Common questions about the Pacific Northwest
What hardiness zone is the Pacific Northwest?
The Pacific Northwest spans USDA hardiness zones 7a-10a, aggregated from the USDA Agricultural Research Service Plant Hardiness Zone Map 2023 across the region's counties. Zones reflect average annual extreme minimum temperatures from 1991–2020 data.
How long is the growing season in the Pacific Northwest?
Measured between 28°F hard freezes, the Pacific Northwest's counties mostly run 243 to 287 frost-free days, median 256 (NOAA Regional Climate Centers ACIS, 1991–2020, over 39 member counties). That 44-day spread is the honest read — no single season describes 39 counties, and each county guide below carries its own.
When does frost risk end in the Pacific Northwest?
Across the Pacific Northwest, the middle half of member counties see their last 28°F hard freeze between Feb 16 and Mar 25 (median Mar 10), and their first fall freeze between Nov 16 and Nov 28. Those are hard freezes, not the last light frost: tender transplants wait for about Mar 31, and elevation decides which end of a 37-day spread you garden in.
What grows well in the Pacific Northwest?
The Pacific Northwest's conditions suit plants such as Tomato, Kale, Potato, Fig, California Poppy, Artichoke. What actually thrives on any one site still turns on its specific soil, sun, and drainage — we score each plant against the real conditions at your address.
How is the Pacific Northwest defined?
The Pacific Northwest's footprint follows an EPA Level III ecoregion — a boundary drawn where climate, soils, and vegetation actually change rather than where a state line falls. It covers 39 counties, and the counties linked on this page are representative of the region, not an exhaustive list.
Which states does the Pacific Northwest cover?
The Pacific Northwest spans California, Oregon, and Washington. Each state's full growing guide is linked on this page.
What other growing regions cover the same states?
Columbia Basin, California Central Valley, Willamette Valley, Sacramento Valley, San Joaquin Valley, and Sierra Nevada Foothills share at least one state with the Pacific Northwest. Growing regions overlap and interlock — a single address can sit inside more than one, which is why the precise read is always the parcel, not the region.
What this page reads at the Pacific Northwest’s own scale
6 of the readings below were taken at the Pacific Northwest's own scale — the zone 7a-10a band across its footprint, a median 256-day season across its 39 counties and 43,366 documented federal contamination records across its 39 counties, 6,301 of them in King County alone; one is borrowed from a wider read, named and linked below.
Measured here
- The USDA hardiness band 7a-10a aggregated across all 39 counties in the footprintUSDA PHZM 2023
- The boundary itself — the EPA Level III ecoregion its 39 counties sit inside, drawn where climate and soils changeEPA Level III Ecoregions
- The growing character that makes this region distinct from the states it crossesGrowable Ground subregion registry
- The 28°F season across the footprint — the middle half of its 39 counties run 243 to 287 frost-free days, median 256NOAA Regional Climate Centers ACIS, 1991-2020
- The federal contamination record over the whole footprint — 43,366 documented federal contamination records across its 39 counties, 6,301 of them in King County aloneEPA, USGS and USDA federal site records
- The soil order mix across the footprint — 33% Inceptisols, topsoil pH 4.6–7.0, area-weighted across its 39 mapped countiesUSDA NRCS SSURGO
Inherited from a wider read
- The candidate plant list — all 3 member states' curated sets, merged and filtered to zones 7a-10afrom California, Oregon and Washington
What this page can’t tell you
- Which end of the 44-day range your ground sits at — 243 days at one extreme, 287 at the other, decided mostly by elevationfrost dates explained →
- Which of those soils your own ground sits on — the survey maps them county-wide, and they change across a drivewaysoil types explained →
- The soil pH, drainage, sun hours, and frost pockets on one specific lotwhy one lot differs from the next →
Explore the Pacific Northwest
State growing guides
Representative counties
Other growing regions across California, Oregon, and Washington
A dry basalt plateau of loess soils in the inland Northwest where irrigation turns arid ground into apple, cherry, hop, and wine-grape country.
A vast flat alluvial trough with hot dry summers and rich soils — one of the most productive agricultural regions on earth, from almonds and stone fruit to row crops.
Oregon's broad maritime valley pairs deep alluvial soils with cool wet winters and dry summers — the heart of the state's hazelnut, berry, and Pinot country.
The cooler, wetter northern half of the Central Valley — rice, walnuts, tomatoes, and orchard fruit on rich alluvial bottomland.
The hot southern half of California's Central Valley — deep soils and intense sun behind almonds, stone fruit, grapes, and row crops at vast scale.
California's Gold Country foothills — rocky, well-drained slopes and warm days that suit wine grapes, olives, and Mediterranean orchard crops.