Washington spans USDA hardiness zones 4a-9b, with a growing season of about 208 frost-free days — a generous window with room for succession plantings and warm-season crops that need time to finish.
The climate hand here is 6-90 inches of annual rainfall, a median of roughly 1,740 growing-degree days (base 50°F), and about 2,500 winter chill hours for tree fruit — the numbers that decide what ripens comfortably and what runs out of runway. On the soil map, volcanic ash, silt loam (Palouse), sandy loam, and glacial outwash dominate — and drainage is the trait that separates an easy bed from a project. Growing in Washington really means growing in one of its distinct regions — Pacific Northwest, Columbia Basin, and Puget Sound Lowlands — each with its own zone band and frost rhythm. These conditions suit apple, cherry, hop, and grape — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Grounded inUSDA PHZM•NOAA Climate Normals•USDA NRCS SSURGO•GDD (PRISM 1991-2020 normals)•Chill hours (PRISM 1991-2020 normals)•USDA hardiness sub-region map•EPA FRS•USDA PLANTS•Growable Ground suitability scoring
Washington spans zones 4a-9b, but your yard 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 Washington — soil, climate, flood, and parcel records. How we handle your address.
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Distinct growing regions within Washington — each has its own zones, soils, and signature crops.
Washington: USDA zones 4a-9b, 131–300 frost-free days depending on the county, 39 counties.
The middle half of this state’s counties. Tender transplants usually wait 2–3 weeks past the last hard freeze. The shortest-season figure is Washington's own county record — Whatcom County's measured 28°F normal, not a modeled floor.
Zone 4a-9b is Washington's average, not your lot's — a low corner or a tree line moves it. Against Washington's 208-day season, see what your own ground reads.
One answer for Washington averages 39 counties whose growing seasons are 169 days apart — from 131 frost-free days in Whatcom County to 300 in San Juan County. That is the same state, measured the same way, in the same years. Which end of it your county sits nearer decides what finishes 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 counties, each carrying its own 28°F normal. NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze. A county with no record of its own is absent from the range rather than counted as zero — nothing here is interpolated to the state. Your own site sits somewhere inside this range; a parcel report resolves where.
The middle half of Washington runs 192–248 frost-free days, and 18 of its 39 counties sit outside that — 9 on the short side, 9 on the long. A statewide planting date describes the middle well and the ends poorly, which is worth knowing before you follow one.
Under 192 frost-free days
9 counties
3 of 9 shown
The end of the state that sets the planting calendar — start seed indoors here and the season stretches to meet the crop.
192–248 frost-free days
21 counties
0 of 21 shown
The middle half of the state, and the part a single statewide date describes well.
Over 248 frost-free days
9 counties
3 of 9 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, county 28°F killing freeze), the same figure its own guide page publishes. Elevation, slope and cold-air drainage move a yard within its county as well — which is the part only your address resolves.
The soil types that dominate Washington — how each drains decides more about crop success than almost anything else. Tap any soil to learn what it is and how to work with it. Each photo is a representative profile of that soil type; the named series is where it was documented, which is often another state.
Drainage
Excellent and unusual: ash soils drain freely yet hold remarkable amounts of plant-available water in their porous structure — the best of both habits.
What thrives
Volcanic regions grow celebrated crops the world over: orchards, berries, vegetables, coffee, and wine grapes all prosper on ash-derived soils.
Drainage
Moderate. Silt holds water well and releases it steadily, though the fine particles can crust after hard rain and compact under traffic.
What thrives
The full vegetable garden does well here, and small grains, corn, and leafy greens are classic silt-loam crops. Its steady moisture suits shallow-rooted plants that dislike drought stress.
Drainage
Fast. The sand fraction opens the soil up, so water moves through the root zone quickly and the surface rarely stays soggy. The trade is that nutrients ride out with the water.
What thrives
Root crops love it — carrots, potatoes, radishes, and onions size up cleanly in ground they can push through. Melons, sweet potatoes, asparagus, and most herbs appreciate the warmth and the drainage.
Drainage
Fast and deep. Outwash plains are among the best-drained ground in the glaciated states.
What thrives
Root crops, asparagus, bush fruits, and orchard trees on drought-tolerant rootstocks. Anything that resents wet feet considers outwash a gift.
Drainage
Usually good: rivers sort their loads, and most alluvial soils have enough sand and silt to move water while holding plenty for roots. Low-lying pockets can run wet.
What thrives
Nearly everything — vegetables, orchards, vines, and berries all prosper on alluvium. Its depth lets roots go as far down as they care to.
Soil data: USDA NRCS SSURGO · Soil types explained
Plants well-suited to Washington's climate, soils, and growing season — each links to its full growing profile.
For most of the year, no — what changes is which crops still fit the days remaining. Across Washington, cool-season planting typically opens about four weeks before the local last hard freeze — county medians put that freeze near Apr 5, with the middle half of counties between Mar 16 and Apr 15 (NOAA 1991–2020 climate normals). Tender transplants wait two to three weeks past it, and fall planting counts back from first freezes mostly between Oct 24 and Nov 18 — long-season crops need about 90 days of runway, quick greens only 30. A long window like this one runs successions deep into fall — and even its last weeks take quick greens and garlic.
The plants Washington put its name on — cultural emblems, not growing recommendations.
Coast rhododendron
Rhododendron macrophyllum
Designated 1892.
Western hemlock
Tsuga heterophylla
Designated 1947.
Walla Walla sweet onion
Designated 2007.
Plants the USDA PLANTS Database documents as native and present in Washington — a real per-state range, not just a zone match. Ordered by how closely each plant’s published hardiness range matches Washington’s zones 4a-9b, so this is a shortlist by climate fit, not a ranking of which plants matter most here. Presence is statewide, so a plant may still be uncommon in your specific county; your state’s Cooperative Extension or a native-plant society is the local authority.
US-native plants whose hardiness range overlaps Washington’s USDA zones 4a-9b but which USDA PLANTS doesn’t map to a single state range here. Zone overlap is a starting filter, not a range map.
What an experienced grower plans around here — each one has a move.
Extreme rain divide: 90+ inches west, 6 inches east of Cascades
Plant to your side of the Cascades, not to the state — your exact spot's rainfall decides the whole plan.
East side requires irrigation — no rain from June through September
With no summer rain, drip lines and deep mulch are the growing season — set them up before June.
Slug and root rot pressure on the wet west side
Raise the beds, bait the slugs, and water mornings only — the wet-side trio that keeps roots and leaves healthy; extension has the details.
Short seasons at elevation in the Cascades and northeast corners
In the short-season corners, fast varieties plus a cold frame or tunnel reliably close the gap.
For cultivar selection, pest pressure, and planting-time guidance specific to Washington, the WSU Extension is the authoritative local source.
Safe to Grow Here?What the federal record shows across Washington — and how to grow with it.
We checked the federal record across Washington — 33,912 documented sites across 8 of the 9 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 with clean imported soil grow well almost anywhere in the meantime.
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 — 1.8M documented sites tracked nationwide across 9 federal source types.
Everything above resolves to Washington as a whole — a state whose own counties record seasons 169 days apart, and hardiness across zones 4a-9b. 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 state 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 statewide average.
State averages sketch the shape. Your soil, sun exposure, drainage, and microclimate decide what actually takes. Pull a site-specific report for your exact parcel.
Enter your address. We read your soil, sun, drainage, and frost dates, then score 1,086 plants against the real conditions on your land.
Three things about your lot that Washington 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 average
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read per county and aggregated to the state band; the growing season from NOAA Regional Climate Centers ACIS 1991–2020 28°F normals, read at each county’s own record; rainfall from NOAA Climate Normals; soils from USDA NRCS SSURGO; boundaries from US Census TIGER/Line 2025; the contamination record from the federal sources named in that beat above. Where a county carries no record of its own, it is absent from the figure rather than filled in.
Washington spans USDA hardiness zones 4a-9b — which is to say winter's coldest night runs from about −30°F to 30°F depending where in Washington you are, averaged over 1991–2020 (USDA PHZM 2023).
For most of the year, no — what changes is which crops still fit the days remaining. Across Washington, cool-season planting typically opens about four weeks before the local last hard freeze — county medians put that freeze near Apr 5, with the middle half of counties between Mar 16 and Apr 15 (NOAA 1991–2020 climate normals). Tender transplants wait two to three weeks past it, and fall planting counts back from first freezes mostly between Oct 24 and Nov 18 — long-season crops need about 90 days of runway, quick greens only 30. A long window like this one runs successions deep into fall — and even its last weeks take quick greens and garlic.
Across Washington, the middle half of counties see their last hard freeze (28°F) between about Mar 16 and Apr 15, with a county median near Apr 5 (NOAA 1991–2020 climate normals). That marks the hard freeze, not the last light frost — lighter frosts keep biting past it, which is why tender transplants here wait until about Apr 26.
Measured between 28°F hard freezes, growing seasons across Washington's counties mostly run about 193 to 246 days, with a county median near 208 (NOAA 1991–2020 climate normals). Tender crops get a somewhat shorter practical window, since lighter frosts reach a few weeks past the hard-freeze dates on both ends.
Washington's zones 4a-9b support a wide range — strong performers include Apple, Cherry, Hop, Grape, and Blueberry. What actually takes on any one site comes down to its soil, sun, and drainage, and we score each plant against the real conditions at your address.
Officially, Washington spans USDA zones 4a-9b (USDA PHZM 2023) — but a zone is a 30-year average of winter's coldest night across an area, and it can't see any one yard. A south-facing slope, a tree line, or a low frost pocket can shift a single site by half a zone either way, which is why neighboring gardeners often quote different numbers. We read the conditions at your exact address — soil, sun, slope, and frost — and score 1,086 plants against what's actually there.
The federal record across Washington runs heavier than most — 33,912 documented sites, mostly Underground Storage Tanks entries (16,413) — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
Start with three facts. Washington spans USDA zones 4a-9b, which sets what survives winter; last hard freezes range from about Mar 16 to Apr 15 across its counties (NOAA 1991–2020 climate normals); and 33,912 documented sites sit on the federal record here, so a soil test before food beds is the smart first step. From there, matching plants to your actual soil and sun is the fun part.
Everything above is measured at Washington's scale — its 4a-9b band and its 208-day season. Your yard writes its own version of Washington's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
6 of the readings below were taken at Washington's own scale — the full zone 4a-9b span inside its borders, the 5 soil types that dominate its ground and 33,912 documented sites on its federal record; anything it cannot resolve at this scale is named below.
Measured here
What this page can’t tell you
Explore growing conditions by county — each has its own zone range and land area.
Explore growing conditions by city or town in Washington.
Washington shares its dominant growing region with these states — a useful comparison if you're weighing where a crop will behave the same way.
