Spokane County, in Washington, sits in USDA hardiness zone 6b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
On paper, cabbage, hazelnut, lavender, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Spokane County lies within the Inland Northwest (Northeast Washington) — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Spokane County holds more than one microclimate.
Soils and elevations shift across Spokane County, so your frost dates and drainage aren't the county average. 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 Spokane County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Spokane County — the short answer
Spokane County, Washington: USDA zone 6b, about 202 days between hard freezes, across 1.1M acres.
- USDA zone
- 6b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 8
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 27
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~202
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 1.1M acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are county 28°F normals: light frosts run a few weeks past them, and tender transplants usually wait 2–3 weeks after the last hard freeze.
Hardiness Zone Range
Zone 6b is Spokane County's average, not your lot's — a low corner or a tree line moves it. Against Spokane County's 202-day season, see what your own ground reads.
Heat in Spokane County
Across a year, Spokane County accumulates about 1,924 growing degree days above 50°F, about 211 more than the middle Washington county — ahead of 29 of Washington’s 39 counties. Degree days are the heat a crop actually gets to work with — more of them is more room to ripen a long-season crop before the freeze closes the window.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Spokane County
Across Spokane County, the ground is predominantly Mollisols, where Naff, Rockly, and Cheney are the most extensive named soil series. The soil is generally well drained with a ashy silt loam surface. Topsoil pH runs about 6.2–6.6, slightly acidic. Rainfall drains through hydrologic group C soils.
Soil order
Mollisols
Drainage
Well drained
Prime farmland
11%
Hydric soils
5%
Soil still varies lot by lot — soil types explained.
How the ground varies across Spokane County
The USDA soil survey maps 76% of Spokane County as well drained — but another 17% drains differently: 7% moderately well drained, 5% somewhat excessively drained.
Naff is the most extensive named soil at 8% of mapped acres, then Rockly (7%) and Cheney (4%).
Which of them your own lot sits on is a parcel question, not a county one. Check your address for the survey at your boundary.
What this means for growing in Spokane County
Each reading below is measured for Spokane County itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Drainage
MeasuredThe dominant soils across Spokane County are well drained, in hydrologic group C — ground that drains quickly.
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
MeasuredTopsoil across Spokane County runs about pH 6.2–6.6, close to neutral.
This is the range most vegetables prefer — one correction you probably do not have to make, which is genuinely good news for a new bed.
Keep it there with compost rather than lime or sulfur, and only amend if your own soil test says otherwise.
USDA NRCS SSURGO
Season length
MeasuredSpokane County runs about 202 days between hard freezes — 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
MeasuredSpokane County sits in USDA hardiness zone 6b.
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 Spokane County is in
Spokane County spans 2 EPA Level III ecoregions — Columbia Plateau (56%) and Northern Rockies (44%). Which one your land falls in changes what grows wild there and how the ground behaves, and a county-wide answer cannot tell you which.
What Grows in Spokane County
We scored all 1,086 plants against Spokane County's own USDA zone 6b and its own 202-day season between hard freezes, using the same matching engine that runs a full parcel report. These cleared both. Sun, soil pH and drainage vary lot by lot — those are the parcel questions below. Each card opens that plant's Washington profile.
Is it too late to plant in Spokane County?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Mar 11; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 8 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 27 — 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.
Documented around Spokane County
- monarch butterfly3 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Spokane County
USGS estimates 35,072 lb of Glyphosate on Spokane County farmland in 2019, its largest by weight, ahead of 2,4-d (33,512 lb) and Bromoxynil (12,801 lb).
Farmland across the whole county, not any one lot. Check your address for the site-by-site record.
Safe to Grow Here?
What the federal record shows across Spokane County — and how to grow with it.
We checked the federal record across Spokane County — 2,118 documented sites across 8 of the 9 source types we track.
The most significant on record: 19 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Spokane County 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.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Spokane County
Closest first, across Spokane County. Listing isn't leaking, and distance isn't exposure.
- JEFFERSONUnderground Storage Tanks · 350 ft
- DIVINE CORPUnderground Storage Tanks · 350 ft
- DIVINE'S SOUTHHILL TOWINGUnderground Storage Tanks · 400 ft
- TEXACO 605Underground Storage Tanks · 500 ft
- WILFRED L NOWLAN SRUnderground Storage Tanks · 2100 ft
- SHERWIN WILLIAMS STORE 708015Brownfields · 2300 ft
- ROCKET MARKET BAKERY AND CAFEUnderground Storage Tanks · 2300 ft
- DIVINE CORP 14Underground Storage Tanks · 0.5 mi
- MANITO GOLF & COUNTRY CLUBUnderground Storage Tanks · 0.5 mi
- RITE AID EXPRESS PHOTO 29TH AVEBrownfields · 0.6 mi
- WALGREENS 10946Brownfields · 0.6 mi
- SPOKANE FIRE DEPARTMENT STATION 11Underground Storage Tanks · 0.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Spokane County'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 Spokane County.
Severity Distribution
across Spokane County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Spokane County, PFAS runs higher than the national average — 24 sites across Spokane County. That's not a problem with your land — it's information about it.
PFAS: PFAS (per- and polyfluoroalkyl substances) are called "forever chemicals" because they do not biodegrade.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Check your specific parcel in Spokane County
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 Spokane County average
Your land is one point inside Spokane County
Everything above resolves to Spokane County as a whole — one PHZM band and one county frost record, read across 1.1M acres. 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 county 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 county average.
Your Lot vs the Spokane County Average
Spokane County Average
- ●USDA Zones 6b, averaged across Spokane County
- ●One soil character for all of Spokane County
- ●Frost dates read at Spokane County's scale: Apr 8 to Oct 27
YOUR Parcel
- ✓Your exact zone, not Spokane County's 6b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Spokane County
Pull a site-specific report for your exact address in Spokane County, Washington — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Spokane County averages can't show:
We read public map data around Spokane County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Spokane County average
How we know this about Spokane County
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at county grain; hard-freeze dates from NOAA 1991–2020 28°F normals at this county’s own record where one resolves, and the labelled statewide window where none does; soils from the USDA NRCS SSURGO survey, area-weighted across the county’s own map units; boundaries and acreage from US Census TIGER/Line 2025; the contamination and pesticide records from the federal sources named in their beats above. Where Spokane County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Spokane County
When does frost risk typically end in Spokane County?
The last hard freeze (28°F) in Spokane County typically lands around Apr 8, 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 29.
How long is the growing season in Spokane County?
Measured between 28°F hard freezes, Spokane County sees about 202 frost-free days — roughly Apr 8 through Oct 27, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 29 to Oct 13, about 167 days.
Is the soil safe to grow vegetables in Spokane County?
The federal record around Spokane County runs heavier than most — 2,118 documented sites, mostly Underground Storage Tanks entries (1,186), the nearest Underground Storage Tanks record under a tenth of a mile out — 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.
Everything above is measured at Spokane County's scale — its 6b band and its 202-day season. Your yard writes its own version of Spokane County's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
Will It Grow Here?
Zone fit is the first question — each answer below reads Washington's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Spokane County’s own scale
9 of the readings below were taken at Spokane County's own scale — its own ~202-day span between 28°F freezes, the 3 most extensive soil series mapped here and 2,118 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Spokane County's own USDA hardiness band, zones 6bUSDA PHZM 2023
- Spokane County's own 28°F hard-freeze dates and its ~202-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Spokane CountyUSDA NRCS SSURGO
- 2,118 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Underground Storage Tanks record under a tenth of a mile outFederal environmental registers
- Spokane County's boundary and the 1,129,102 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6b and a ~202-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Spokane County spans, Columbia Plateau the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Spokane County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Spokane County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Washington grower plans around — written at state scale, so they stay on the state guidefrom Washington
What this page can’t tell you
- How the season shifts across Spokane County — the ~202 days above is one reading at its centre; the 12 towns below each carry their owntowns in this county →
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Spokane County's 1,129,102 acreswhy one lot differs from the next →
- Which of those 2,118 documented sites actually reaches your soil — that needs your address, the wind, and the groundwater directionhow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — none of it survives being averaged over Spokane Countyread your own land →