The Northeast Oregon Mountain Valleys spans USDA hardiness zone 6b — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Unlike Oregon's mild westside valleys or the arid low Columbia Basin, Northeast Oregon's mountain valleys are a cold, high-elevation growing world — irrigated valley floors above 2,700 feet ringed by the Blue and Wallowa Mountains, where nightly cold-air pooling makes late-spring and early-fall frosts the defining constraint. Expect USDA zone 6b and a short ~150-165 frost-free-day season, a calendar that rewards short-season and cold-hardy crops, season extension, and careful frost timing over anything heat-loving. Well-matched crops include kale, garlic, hazelnut, and blueberry, and the gap between "grows in the area" and "grows in your yard" is closed by soil, sun, and drainage.
The Northeast Oregon Mountain Valleys spans Oregon.
Your yard isn't all of the Northeast Oregon Mountain Valleys.
The Northeast Oregon Mountain Valleys spans USDA zones 6b, but your parcel sits in exactly one — and slope, tree cover, and low spots nudge it further. 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 Northeast Oregon Mountain Valleys — soil, climate, flood, and parcel records. How we handle your address.
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The Northeast Oregon Mountain Valleys — the short answer
The Northeast Oregon Mountain Valleys: USDA zones 6b, 150–165 frost-free days, in Oregon.
- USDA zones
- 6b
- USDA PHZM 2023, aggregated over the footprint
- Frost-free season
- 150–165 days
- NOAA Regional Climate Centers ACIS, 1991-2020
- Counties
- 4
- US Census TIGER/Line 2025
- Region type
- County cluster
- Growable Ground growing-region registry
Region boundary: Growable Ground growing-region registry — curated county clusters, EPA Level III ecoregions, and town clusters drawn finer than any county. Where a region publishes no measured season, no season figure is shown.
Hardiness Zone Range
What Grows in the Northeast Oregon Mountain Valleys
Plants matched to the Northeast Oregon Mountain Valleys' USDA zones 6b, ordered by how much hardiness margin each has across the region — the ones with room to spare at both ends of this band lead. Each links to its full growing profile.
Native Plants of the Northeast Oregon Mountain Valleys
Plants the USDA PLANTS Database documents as native and present in this region’s state, kept only where the published hardiness range meets the Northeast Oregon Mountain Valleys’s USDA zones 6b — closest range match first. Presence is recorded by state, so a plant can be documented across the state and still be scarce in your corner of the region.
The ground across the Northeast Oregon Mountain Valleys
The USDA soil survey maps this ground county by county. These are those records weighted by land area across four member counties — this region’s own profile, not a state figure.
The ground is predominantly Mollisols, at 45% of mapped acres, followed by Andisols (35%), Inceptisols (15%) and Alfisols (4%). Eight soil orders appear somewhere inside the footprint, which is the honest reason a regional soil answer only goes so far. The most extensive named soils are Limberjim, Anatone, and Syrupcreek.
88% of those acres are well drained, and another 1% moderately well drained, 1% somewhat poorly drained. Topsoil pH runs 6.1–7.0 between the lowest and the highest county on record. 1% of the footprint is classed prime farmland.
Soil order
Mollisols
Drainage
Well drained
Topsoil pH
6.1–7.0
Hydric soils
1%
Soil changes across a driveway, so which of these your own ground sits on is a parcel question rather than a regional one. Baker County holds the most wetland ground here, at 2% — soil types explained.
USDA NRCS SSURGO via Soil Data Access
What this means for growing in the Northeast Oregon Mountain Valleys
The soil survey reads this ground county by county, and the readings above are those records summed across the Northeast Oregon Mountain Valleys. Here is what they mean for a garden here — and the move an experienced grower makes about each one.
Drainage
From county records88% of the mapped acres across the Northeast Oregon Mountain Valleys are well drained — ground that drains quickly. That is area-weighted across all four of its mapped counties.
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
From county recordsTopsoil across the Northeast Oregon Mountain Valleys runs pH 6.1–7.0 — near neutral in all four of them.
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
Safe to Grow Here?
What the federal record shows across the Northeast Oregon Mountain Valleys — and how to grow with it.
Across the Northeast Oregon Mountain Valleys' 4 counties the federal record holds 1,471 documented sites, mostly Mining (974), Underground Storage Tanks (377) and Brownfields (55). The heaviest single county is Grant County, with 527.
That is a regional count, not a reading of any one lot — proximity to a documented site is information, not a diagnosis. Open the map outlined to the Northeast Oregon Mountain Valleys to see which records sit where you actually grow.
Sources Checked
Summed across the 4 counties in the Northeast Oregon Mountain Valleys
A note from Gnorman
What an experienced grower watches for around here
In and around the Northeast Oregon Mountain Valleys, two things run higher than the national average across the 4 counties in the Northeast Oregon Mountain Valleys — Mining (974 sites) and Superfund (24 sites). That's not a problem with your land — it's information about 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).
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
Your land is one point inside the Northeast Oregon Mountain Valleys
Everything above resolves to the Northeast Oregon Mountain Valleys as a whole — a footprint spanning USDA zones 6b. Your parcel sits in exactly one of them. 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 region 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 regional average.
Your Lot vs the Northeast Oregon Mountain Valleys Average
Northeast Oregon Mountain Valleys Average
- ●USDA Zones 6b, averaged across Northeast Oregon Mountain Valleys
- ●One soil character for all of Northeast Oregon Mountain Valleys
- ●State-average frost dates
YOUR Parcel
- ✓Your exact zone, not Northeast Oregon Mountain Valleys' 6b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in the Northeast Oregon Mountain Valleys
Pull a site-specific report for your exact address in the Northeast Oregon Mountain Valleys — soil, sun, drainage, frost risk, contamination, and scored plant recommendations.
Three things about your lot that Northeast Oregon Mountain Valleys averages can't show:
We read public map data around The Northeast Oregon Mountain Valleys — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Northeast Oregon Mountain Valleys average
How we know this about the Northeast Oregon Mountain Valleys
The boundary: a cluster of neighboring counties. Growing regions have no official boundary, so this footprint is our published one, and every figure on this page was measured over the counties inside it rather than borrowed from the state around it.
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, aggregated across the footprint; the growing season from NOAA Regional Climate Centers ACIS 1991–2020 28°F normals, read at each member’s own record; boundaries from US Census TIGER/Line 2025; the contamination record from the federal sources named in that beat above; the soil from the USDA NRCS SSURGO survey, read at each member county’s own record and weighted to this footprint by land area. Where a member carries no record of its own, it is absent from the figure rather than filled in.
Common questions about the Northeast Oregon Mountain Valleys
What hardiness zone is the Northeast Oregon Mountain Valleys?
The Northeast Oregon Mountain Valleys spans USDA hardiness zones 6b, aggregated from the USDA Agricultural Research Service Plant Hardiness Zone Map 2023 across the region's counties. Zones reflect average annual extreme minimum temperatures from 1991–2020 data.
How long is the growing season in the Northeast Oregon Mountain Valleys?
Measured between 28°F hard freezes, the Northeast Oregon Mountain Valleys' counties mostly run 158 to 164 frost-free days, median 162 (NOAA Regional Climate Centers ACIS, 1991–2020, over 4 member counties). That 6-day spread is the honest read — no single season describes 4 counties, and each county guide below carries its own.
When does frost risk end in the Northeast Oregon Mountain Valleys?
Across the Northeast Oregon Mountain Valleys, the middle half of member counties see their last 28°F hard freeze between Apr 30 and May 5 (median May 4), and their first fall freeze between Oct 6 and Oct 11. Those are hard freezes, not the last light frost: tender transplants wait for about May 25, and elevation decides which end of a 5-day spread you garden in.
What grows well in the Northeast Oregon Mountain Valleys?
The Northeast Oregon Mountain Valleys' conditions suit plants such as Kale, Garlic, Hazelnut, Blueberry, Hop, Douglas Fir. What actually thrives on any one site still turns on its specific soil, sun, and drainage — we score each plant against the real conditions at your address.
How is the Northeast Oregon Mountain Valleys defined?
The Northeast Oregon Mountain Valleys is defined here as a curated cluster of 4 neighboring counties that share a growing character. Growing regions have no official boundary, so this footprint is our published one — every county in it is named on this page.
Which states does the Northeast Oregon Mountain Valleys cover?
The Northeast Oregon Mountain Valleys spans Oregon. Each state's full growing guide is linked on this page.
What other growing regions cover the same states?
Pacific Northwest, Columbia Basin, Willamette Valley, Oregon Coast (Maritime Cool-Summer Strip), Columbia Gorge, and Central Oregon (High Desert) share at least one state with the Northeast Oregon Mountain Valleys. Growing regions overlap and interlock — a single address can sit inside more than one, which is why the precise read is always the parcel, not the region.
What this page reads at the Northeast Oregon Mountain Valleys’s own scale
6 of the readings below were taken at the Northeast Oregon Mountain Valleys' own scale — the zone 6b band across its footprint, a median 162-day season across its 4 counties and 1,471 documented federal contamination records across its 4 counties, 527 of them in Grant County alone; one is borrowed from a wider read, named and linked below.
Measured here
- The USDA hardiness band 6b aggregated across all 4 counties in the footprintUSDA PHZM 2023
- The boundary itself — the 4 counties this region is curated fromGrowable Ground subregion registry
- The growing character that makes this region distinct from the states it crossesGrowable Ground subregion registry
- The 28°F season across the footprint — the middle half of its 4 counties run 158 to 164 frost-free days, median 162NOAA Regional Climate Centers ACIS, 1991-2020
- The federal contamination record over the whole footprint — 1,471 documented federal contamination records across its 4 counties, 527 of them in Grant County aloneEPA, USGS and USDA federal site records
- The soil order mix across the footprint — 45% Mollisols, topsoil pH 6.1–7.0, area-weighted across its 4 mapped countiesUSDA NRCS SSURGO
Inherited from a wider read
- The candidate plant list — its state's curated sets, merged and filtered to zones 6bfrom Oregon
What this page can’t tell you
- Which end of the 6-day range your ground sits at — 158 days at one extreme, 164 at the other, decided mostly by elevationfrost dates explained →
- Which of those soils your own ground sits on — the survey maps them county-wide, and they change across a drivewaysoil types explained →
- The soil pH, drainage, sun hours, and frost pockets on one specific lotwhy one lot differs from the next →
Explore the Northeast Oregon Mountain Valleys
State growing guides
Counties in this region
Other growing regions across Oregon
The maritime Northwest west of the Cascade crest — mild, wet winters and dry summers behind berries, tree fruit, and lush cool-season gardens. (Union of the west-side ecoregions.)
A dry basalt plateau of loess soils in the inland Northwest where irrigation turns arid ground into apple, cherry, hop, and wine-grape country.
Oregon's broad maritime valley pairs deep alluvial soils with cool wet winters and dry summers — the heart of the state's hazelnut, berry, and Pinot country.
Unlike the inland Willamette Valley captured by the broad Pacific Northwest region, the Oregon coast runs the opposite constraint: persistent marine fog holds summer heat so low that tomatoes, peppers, melons, and sweet corn rarely ripen — yet the same maritime air delivers a 263–308-day frost-free season (per county_data.json) where brassicas, greens, and other cool-season crops thrive nearly year-round. Curry County's south-coast banana belt around Brookings (zone 9b, the mildest winters in Oregon) anchors the U.S. Easter lily bulb district. Lead a coastal grower to plan for cool-season abundance and short-season or greenhouse strategies for heat-lovers — not the inland valley's frost-limited but heat-rich pattern.
A river canyon cut through the Cascades where wet marine air gives way to high desert in forty miles — pear, cherry, and apple orchards at the west end, vineyards and dryland ground at the east.
Central Oregon is a cold, arid high-desert plateau east of the Cascade crest — a fundamentally different growing world from the mild Willamette Valley just over the mountains. Where valley gardens run a 240-290 day frost-free season in USDA zones 8-9, Bend, Redmond, Prineville, and Madras sit at roughly 3,000-3,600 ft in zones 6b-7a with only a ~150-175 day frost-free window, and a hard frost is possible in any month. Large day-to-night temperature swings and low humidity mean growers here plan around season extension — row cover, cold frames, hoop houses — rather than counting on long-season heat-lovers to ripen on their own.