What Grows in Asotin County, Washington

USDA Zones 7a · 407K acres

Asotin County, in Washington, sits in USDA hardiness zone 7a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.

Expect apple, cherry, hop, and grape to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.

Asotin 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

Score your parcel · free

Asotin County holds more than one microclimate.

Soils and elevations shift across Asotin 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

7a

Last Hard Freeze (28°F)

Apr 10

County normal — light frosts run a few weeks later

First Hard Freeze (28°F)

Nov 1

County normal — light frosts arrive a few weeks earlier

County Area

407K acres

Hardiness Zone Range

7a7a
3a (Cold)13b (Hot)

Zone maps are averages across Asotin County. Your yard's slope, trees, and frost pockets shift what actually grows — see your land's exact reading.

Soil in Asotin County

Across Asotin County, the ground is predominantly Mollisols, where Limberjim, Anatone, and Larabee are the most extensive named soil series. The soil is generally well drained with a ashy silt loam surface. Topsoil pH runs about 6.5–7.0, neutral. Rainfall drains through hydrologic group D soils.

Soil order

Mollisols

Drainage

Well drained

Prime farmland

2%

Hydric soils

0%

Soil still varies lot by lot — soil types explained.

Is it too late to plant in Asotin County?

For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Mar 13; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 10 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 1 — 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.

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 Asotin County — and how to grow with it.

Federal record: Elevated

We checked the federal record across Asotin County104 documented sites across 5 of the 9 source types we track.

The most significant on record: 13 mining sites. Historic and active mines that may leach heavy metals like arsenic, lead, and cadmium.

There's a meaningful federal record across Asotin 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, USGS1.8M 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.

Total Sites

104

across Asotin County

Risk Level

Elevated

Highest-severity

13 mining sites

Severity Distribution

across Asotin County

High3Moderate34Low67

Highest-Severity Sites

Lime Hill Prospects
Mining Sites · Prospect
Pud #1 of Asotin County
PFAS Sampling · PFAS Detected
08N/45E-26k01
Nitrate Monitoring · Well
08N/45E-26k01
Nitrate Monitoring · Well
10N/46E-05q01
Nitrate Monitoring · Well

A note from Gnorman

What an experienced grower watches for around here

In and around Asotin County, two things run higher than the national average — Mining (13 sites) and Underground Storage Tanks (66 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.

Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.

Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.

Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.

Use raised beds with imported soil — this eliminates the primary soil-contact pathway.

Free Report

Check your specific parcel in Asotin 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:

Your soil pHYour frost-free daysYour sun & shade

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

Asotin County Average

  • USDA Zones 7a
  • 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

Free Report

Read your parcel in Asotin County

Pull a site-specific report for your exact address in Asotin County, Washington — soil, sun, drainage, frost risk, and scored plant recommendations.

Three things about your exact spot that zone averages miss:

Your soil pHYour frost-free daysYour sun & shade

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 Asotin County, Washington

  • USDA Hardiness Zones: 7a (USDA PHZM 2023)
  • Last Hard Freeze (28°F): Apr 10 (county normal, NOAA 1991–2020 Climate Normals — light frosts can follow for a few weeks)
  • First Hard Freeze (28°F): Nov 1 (county normal, NOAA 1991–2020 Climate Normals — light frosts can arrive a few weeks earlier)
  • Days Between Hard Freezes: ~205 (county normal, NOAA 1991–2020 Climate Normals)
  • County Land Area: 407K 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 Asotin 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 Asotin County, Washington?

Asotin County sits in USDA hardiness zone 7a, per the USDA Plant Hardiness Zone Map 2023. Zones reflect average annual extreme minimum temperatures from 1991–2020 weather data.

Is it too late to plant in Asotin County?

For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Mar 13; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 10 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 1 — 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.

When does frost risk typically end in Asotin County?

The last hard freeze (28°F) in Asotin County typically lands around Apr 10, per NOAA 1991–2020 climate normals — an earlier marker than the light-frost dates many planting charts quote. That marks the hard freeze, not the last light frost — light frosts can still bite for a few more weeks, so tender transplants usually wait another 2–3 weeks.

How long is the growing season in Asotin County?

Measured between 28°F hard freezes, Asotin County sees about 205 frost-free days — roughly Apr 10 through Nov 1, per 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.

What vegetables grow in Asotin County?

Asotin County's zone 7a 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 Asotin County, really?

Officially, Asotin County sits in USDA zone 7a (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 Asotin County?

The federal record around Asotin County is a meaningful one — 104 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 Asotin County — what should I know before planting?

Start with three facts. Asotin County sits in USDA zone 7a, which sets what survives winter; the last 28°F hard freeze typically clears around Apr 10, with about 205 frost-free days to work with (NOAA 1991–2020 climate normals); and 104 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 Asotin 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.