Okanogan County, in Washington, sits in USDA hardiness zone 6a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Reliable performers under these conditions include cabbage, hazelnut, lavender, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Okanogan County lies within the Columbia Basin — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Okanogan County holds more than one microclimate.
Soils and elevations shift across Okanogan 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 Okanogan County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Okanogan County — the short answer
Okanogan County, Washington: USDA zone 6a, about 192 days between hard freezes, across 3.4M acres.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 15
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 24
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~192
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 3.4M 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 6a is Okanogan County's average, not your lot's — a low corner or a tree line moves it. Against Okanogan County's 192-day season, see what your own ground reads.
Heat in Okanogan County
Across a year, Okanogan County accumulates about 1,807 growing degree days above 50°F, about 94 more than the middle Washington county — ahead of 23 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 Okanogan County
Across Okanogan County, the ground is predominantly Mollisols, where Conconully, Nevine, and Myerscreek are the most extensive named soil series. The soil is generally well drained with a ashy silt loam surface. Topsoil pH runs about 6.3–6.8, slightly acidic. Rainfall drains through hydrologic group B soils.
Soil order
Mollisols
Drainage
Well drained
Prime farmland
2%
Hydric soils
2%
Soil still varies lot by lot — soil types explained.
How the ground varies across Okanogan County
The USDA soil survey maps 79% of Okanogan County as well drained — but another 13% drains differently: 8% somewhat excessively drained, 2% excessively drained.
Conconully is the most extensive named soil at 5% of mapped acres, then Nevine (5%) and Myerscreek (3%).
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 Okanogan County
Each reading below is measured for Okanogan 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 Okanogan County are well drained, in hydrologic group B — 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 Okanogan County runs about pH 6.3–6.8, 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
MeasuredOkanogan County runs about 192 days between hard freezes — a moderate growing season.
There is room for the full run of cool-season crops plus a warm-season main crop, but the calendar is tight enough that a late spring or early fall frost still decides how much finishes.
Time warm-season transplants to your last hard freeze, and a few weeks of season extension turns a near-miss harvest into a sure one.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredOkanogan County sits in USDA hardiness zone 6a.
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 Okanogan County is in
Okanogan County spans 3 EPA Level III ecoregions — North Cascades (49%), Columbia Plateau (26%) and Northern Rockies (25%). 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 Okanogan County
We scored all 1,086 plants against Okanogan County's own USDA zone 6a and its own 192-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 Okanogan County?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Mar 18; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 15 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 24 — long-season crops need about 90 days of runway, quick greens only 30. Even past midsummer there is room for a true fall garden here, and garlic planted near the close carries the momentum into next year.
Documented around Okanogan County
- monarch butterfly8 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Okanogan County
USGS estimates 26,720 lb of Chlorpyrifos on Okanogan County farmland in 2019, its largest by weight, ahead of Glyphosate (22,118 lb) and Triclopyr (21,688 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 Okanogan County — and how to grow with it.
We checked the federal record across Okanogan County — 1,032 documented sites across 8 of the 9 source types we track.
The most significant on record: 16 Superfund sites. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Okanogan 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 Okanogan County
Closest first, across Okanogan County. Listing isn't leaking, and distance isn't exposure.
- WindfallMining · 150 ft
- ChlorideMining · 150 ft
- ArizonaMining · 150 ft
- SunriseMining · 150 ft
- CONCONULLY GENERAL STOREUnderground Storage Tanks · 0.7 mi
- CONCONULLY STATE PARKUnderground Storage Tanks · 0.8 mi
- RONALD B MOTESUnderground Storage Tanks · 0.8 mi
- CONCONULLY WORK CENTERUnderground Storage Tanks · 0.8 mi
- KERR DUMPUnderground Storage Tanks · 0.8 mi
- HURVEY REESEUnderground Storage Tanks · 0.9 mi
- Lady of the LakeMining · 1.1 mi
- Bonnie BessMining · 1.1 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Okanogan 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 Okanogan County.
Severity Distribution
across Okanogan County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Okanogan County, two things run higher than the national average across Okanogan County — Mining (762 sites) and Superfund (16 sites). 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.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in Okanogan 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 Okanogan County average
Your land is one point inside Okanogan County
Everything above resolves to Okanogan County as a whole — one PHZM band and one county frost record, read across 3.4M 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 Okanogan County Average
Okanogan County Average
- ●USDA Zones 6a, averaged across Okanogan County
- ●One soil character for all of Okanogan County
- ●Frost dates read at Okanogan County's scale: Apr 15 to Oct 24
YOUR Parcel
- ✓Your exact zone, not Okanogan County's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Okanogan County
Pull a site-specific report for your exact address in Okanogan County, Washington — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Okanogan County averages can't show:
We read public map data around Okanogan County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Okanogan County average
How we know this about Okanogan 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 Okanogan County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Okanogan County
When does frost risk typically end in Okanogan County?
The last hard freeze (28°F) in Okanogan County typically lands around Apr 15, 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 May 6.
How long is the growing season in Okanogan County?
Measured between 28°F hard freezes, Okanogan County sees about 192 frost-free days — roughly Apr 15 through Oct 24, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 6 to Oct 10, about 157 days.
Is the soil safe to grow vegetables in Okanogan County?
The federal record around Okanogan County runs heavier than most — 1,032 documented sites, mostly Mining entries (762), the nearest Mining 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 Okanogan County's scale — its 6a band and its 192-day season. Your yard writes its own version of Okanogan 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 Okanogan County’s own scale
9 of the readings below were taken at Okanogan County's own scale — its own ~192-day span between 28°F freezes, the 3 most extensive soil series mapped here and 1,032 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Okanogan County's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Okanogan County's own 28°F hard-freeze dates and its ~192-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Okanogan CountyUSDA NRCS SSURGO
- 1,032 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Mining record under a tenth of a mile outFederal environmental registers
- Okanogan County's boundary and the 3,370,360 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~192-day seasonGrowable Ground crop-matching engine
- The 3 ecoregions Okanogan County spans, North Cascades the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Okanogan County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Okanogan 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 Okanogan County — the ~192 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 Okanogan County's 3,370,360 acreswhy one lot differs from the next →
- Which of those 1,032 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 Okanogan Countyread your own land →