Duvall, Washington, sits in USDA hardiness zone 8b — a zone band wide enough that plant choice, not possibility, is the interesting question.
Reliable performers under these conditions include cabbage, fig, california poppy, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Even in Duvall, no two yards are alike.
A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single Duvall lot. 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 Duvall — soil, climate, flood, and parcel records. How we handle your address.
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Duvall — the short answer
Duvall, Washington: USDA zone 8b, about 252 days between hard freezes, across 2K acres of city.
- USDA zone
- 8b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 14
- King County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Nov 21
- King County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~252
- King County normal — NOAA 1991–2020, nearest to this town
- City area
- 2K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. No 30-year normal resolves at this town’s own centroid, so the hard-freeze dates are King County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 8b is Duvall's average, not your lot's — a low corner or a tree line moves it. Against Duvall's 252-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Duvall
Each reading below is measured for Duvall itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsDuvall runs about 252 days between hard freezes (read from King County, the closest normal to Duvall) — a long growing season.
There is slack for succession plantings and slow-finishing crops: many vegetables can be sown twice, and the heat-lovers have time to ripen fully.
Plan a second sowing of quick crops after the first comes out, and use the fall window most gardeners let sit idle.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredDuvall sits in USDA hardiness zone 8b.
The zone sets which perennials, shrubs, and fruit trees live through an average winter here — a plant rated for a colder zone is a safe bet, one rated warmer needs winter protection or gets treated as an annual.
Match perennials and fruit to the zone before you buy, so nothing you plant is a gamble against the cold.
USDA PHZM 2023
The kind of country Duvall is in
Duvall sits in the Puget Lowland — EPA Level III, inside the wider Marine West Coast Forest. That is read at Duvall's own centroid rather than borrowed from King County.
What Grows in Duvall
Every plant below cleared Duvall's own zone 8b and its 252-day season. Each card opens that plant's Washington profile. How we score.
Is it too late to plant in Duvall?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Feb 14; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 14 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 21 — long-season crops need about 90 days of runway, quick greens only 30. Here the season winds down slowly: late sowings, a real autumn harvest, and garlic in the ground before the first hard freeze.
What's on the federal record near Duvall
Closest first, within ~10 miles of Duvall. Listing isn't leaking, and distance isn't exposure.
- FARWEST PETROLEUM COMPANY, LLCUnderground Storage Tanks · 0.7 mi
- VALLEY WINE & SPIRITSUnderground Storage Tanks · 0.8 mi
- Duvall MarketUnderground Storage Tanks · 0.8 mi
- SAFEWAY 1572Brownfields · 0.9 mi
- 26N/06E-13D03Nitrate · 0.9 mi
- SAFEWAY FUEL 1572Underground Storage Tanks · 1.0 mi
- TOLT DUVALL SHOPS WATER DEPARTIONUnderground Storage Tanks · 1.3 mi
- STATION 69Brownfields · 1.7 mi
- DUVALL CITY OFPFAS · 1.8 mi
- DUVALL CENTRAL OFFICE 2060-B02Underground Storage Tanks · 1.8 mi
- WA DOT DUVALL TURNAROUNDUnderground Storage Tanks · 1.9 mi
- PARSONS BROS ROCKERIES INCUnderground Storage Tanks · 2.2 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Duvall's center, not your beds. Run your own address for what's upwind of you specifically.
Environmental Intelligence
The counts behind that headline — every source type on the record near Duvall.
Total Sites
671
within ~10 miles of Duvall
Risk Level
Elevated
Highest-severity
2 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Duvall
Severity Distribution
within ~10 miles of Duvall
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Duvall, two things run higher than the national average within ~10 miles of Duvall — PFAS (8 sites) and Toxics Release Inventory (58 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Check your specific parcel in Duvall
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,086 plant recommendations.
25+ data sources read at your address, not the Duvall average
Your land is one point inside Duvall
Everything above resolves to Duvall as a whole — one PHZM band, read across 2K acres, with hard-freeze dates borrowed from King County’s record because no 30-year normal resolves at this city’s own centroid. Your parcel is one point inside that footprint. 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 city 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 local average.
Your Lot vs the Duvall Average
Duvall Average
- ●USDA Zones 8b, averaged across Duvall
- ●One soil character for all of Duvall
- ●Frost dates read at Duvall's scale: Mar 14 to Nov 21
YOUR Parcel
- ✓Your exact zone, not Duvall's 8b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Duvall
Pull a site-specific report for your exact address in Duvall, Washington — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Duvall averages can't show:
We read public map data around Duvall — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Duvall average
How we know this about Duvall
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at King County’s record, because none resolves here; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at city grain anywhere on this page — there is no city-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about Duvall
When does frost risk typically end in Duvall?
The last hard freeze (28°F) in Duvall typically lands around Mar 14, per NOAA 1991–2020 climate normals — earlier than the light-frost dates most charts quote. 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 4.
When is the first frost in Duvall?
The first hard freeze (28°F) in Duvall typically arrives around Nov 21, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 7, so the watching starts about Oct 22 — about 252 days after the spring freeze cleared.
How long is the growing season in Duvall?
Measured between 28°F hard freezes, Duvall sees about 252 frost-free days — roughly Mar 14 through Nov 21, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 4 to Nov 7, about 217 days.
Is the soil safe to grow vegetables in Duvall?
The federal record around Duvall is a meaningful one — 671 documented sites, mostly Underground Storage Tanks entries (302), the nearest Underground Storage Tanks record about 0.7 miles out — so a soil test before new food beds is a sensible precaution here, not a reason to hold back from growing. Remember that proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what sits where.
How do I protect my plants from frost in Duvall?
From about Oct 22 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Nov 21 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Nov 21. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Duvall's scale — its 8b band and its 252-day season. Your yard writes its own version of Duvall's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at Duvall’s own scale
5 of the readings below were taken at Duvall's own scale — the 1,569 acres it covers and 671 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Duvall's own USDA hardiness band, zones 8bUSDA PHZM 2023
- 671 documented contamination sites on the federal record near Duvall, the closest Underground Storage Tanks record about 0.7 miles out from the town centreFederal environmental registers
- Duvall's boundary and the 1,569 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 8b and a ~252-day seasonGrowable Ground crop-matching engine
- The ecoregion at Duvall's own centroid, the Puget LowlandUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — Duvall has no normal of its own, so its county's is the closest measured readfrom King County
- Soil character — no town-scale survey exists, so Duvall's 1,569 acres read through its county's SSURGO summaryfrom King County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom King County
- The growing challenges every Washington grower plans around — written at state scale, so they stay on the state guidefrom Washington
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom King County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Duvall's 1,569 acreswhy one lot differs from the next →
- Which side of Duvall you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,569 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.7 miles out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any Duvall-wide figureread your own land →