Mason County, in Washington, sits in USDA hardiness zone 8b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Crops well matched to these conditions include apple, cherry, hop, and grape — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Mason County lies within the Pacific Northwest — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring
Mason County holds more than one microclimate.
Soils and elevations shift across Mason County, so your frost dates and drainage aren't the county average. Enter your address and we'll score 1,112 plants against your land's actual soil, sun, and frost.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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Quick Facts
USDA Zones
8b
Last Frost (state avg.)
Mar 1 - Jun 1
First Frost (state avg.)
Sep 15 - Nov 15
County Area
614K acres
Hardiness Zone Range
Growing Season
Zone maps are averages across Mason County. Your yard's slope, trees, and frost pockets shift what actually grows — see your land's exact reading.
Soil in Mason County
Across Mason County, the ground is predominantly Andisols, where Alderwood, Grove, and Shelton are the most extensive named soil series. The soil is generally moderately well drained with a gravelly sandy loam surface. Topsoil pH runs about 5.3–5.8, strongly acidic. Rainfall drains through hydrologic group B soils.
Soil order
Andisols
Drainage
Moderately well drained
Prime farmland
5%
Hydric soils
4%
Soil still varies lot by lot — soil types explained.
What Grows in Mason County
Plants matched to Mason County's USDA zones 8b — each links to its full growing profile.
Growing Challenges in Washington
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 Mason County — and how to grow with it.
We checked the federal record across Mason County — 326 documented sites across 7 of the 9 source types we track.
The most significant on record: 1 Superfund site. Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
There's a meaningful federal record across Mason County — worth a look before you plant food, not a reason to hold back from growing. Proximity to a documented site is information, not a diagnosis of any one yard. A soil test before new food beds is the sensible precaution here, and the map shows exactly which sites sit where, so you can see what's actually near you.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
Environmental Intelligence
Understanding what's nearby helps you make informed decisions about where and how to grow.
Sources Checked
across Mason County
Severity Distribution
across Mason County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Mason County, two things run higher than the national average — PFAS (4 sites) and Nitrate (104 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.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test irrigation water source — this is the primary pathway for PFAS to reach garden crops.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Mason County
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,112 plant recommendations.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
Your Specific Parcel Matters
Mason County Average
- ●USDA Zones 8b
- ●Generic soil type for the area
- ●State-average frost dates
YOUR Parcel
- ✓Your exact hardiness zone
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Mason County
Pull a site-specific report for your exact address in Mason County, Washington — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
Key Growing Facts for Mason County, Washington
- USDA Hardiness Zones: 8b (USDA PHZM 2023)
- Last Spring Frost (state avg.): Mar 1 - Jun 1 (NOAA 30-Year Climate Normals)
- First Fall Frost (state avg.): Sep 15 - Nov 15 (NOAA 30-Year Climate Normals)
- County Land Area: 614K acres (US Census TIGER 2025)
Zone data: USDA ARS Plant Hardiness Zone Map 2023. Climate data: NOAA NCEI. County boundaries: US Census TIGER/Line 2025.
Frost dates here are the Mason County average. Low spots and tree cover move them by days on any one yard — see your exact frost windows.
Frequently Asked Questions
What hardiness zone is Mason County, Washington?
Mason County sits in USDA hardiness zone 8b, per the USDA Plant Hardiness Zone Map 2023. Zones reflect average annual extreme minimum temperatures from 1991–2020 weather data.
When does frost risk typically end in Mason County?
Mason County follows Washington's statewide frost window: last spring frost around Mar 1 - Jun 1 and first fall frost around Sep 15 - Nov 15, per NOAA 30-year climate normals (1991–2020). Frost dates shift with elevation and local microclimate, so watch your own site's cold pockets.
What vegetables grow in Mason County?
Mason County's zone 8b supports 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.
Which hardiness zone is Mason County, really?
Officially, Mason County sits in USDA zone 8b (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 1,112 plants against what's actually there.
Is the soil safe to grow vegetables in Mason County?
The federal record around Mason County is a meaningful one — 326 documented sites — 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.
Just moved to Mason County — what should I know before planting?
Start with three facts. Mason County sits in USDA zone 8b, which sets what survives winter; the statewide frost window runs about Mar 1 - Jun 1 to Sep 15 - Nov 15 (NOAA 30-year climate normals); and 326 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 on this page is a Mason County average. Your yard writes its own version — 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.