Nez Perce County, in Idaho, sits in USDA hardiness zone 7a — a zone band wide enough that plant choice, not possibility, is the interesting question.
Expect cabbage, hazelnut, california poppy, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Nez Perce County lies within the Palouse and 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
Nez Perce County holds more than one microclimate.
Soils and elevations shift across Nez Perce 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 Nez Perce County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Nez Perce County — the short answer
Nez Perce County, Idaho: USDA zone 7a, about 216 days between hard freezes, across 543K acres.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 1
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Nov 3
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~216
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 543K 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 7a is Nez Perce County's average, not your lot's — a low corner or a tree line moves it. Against Nez Perce County's 216-day season, see what your own ground reads.
Heat in Nez Perce County
Across a year, Nez Perce County accumulates about 2,168 growing degree days above 50°F, about 677 more than the middle Idaho county — ahead of 37 of Idaho’s 44 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 Nez Perce County
Across Nez Perce County, the ground is predominantly Mollisols, where Kettenbach, Klickson, and Naff are the most extensive named soil series. The soil is generally well drained with a silt loam surface. Topsoil pH runs about 6.5–7.0, neutral. Rainfall drains through hydrologic group C soils.
Soil order
Mollisols
Drainage
Well drained
Prime farmland
1%
Hydric soils
1%
Soil still varies lot by lot — soil types explained.
How the ground varies across Nez Perce County
The USDA soil survey maps 81% of Nez Perce County as well drained — but another 17% drains differently: 15% moderately well drained, 1% somewhat poorly drained.
Kettenbach is the most extensive named soil at 10% of mapped acres, then Klickson (8%) and Naff (6%).
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 Nez Perce County
Each reading below is measured for Nez Perce 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 Nez Perce 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 Nez Perce County runs about pH 6.5–7.0, 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
MeasuredNez Perce County runs about 216 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
MeasuredNez Perce County sits in USDA hardiness zone 7a.
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 Nez Perce County is in
Nez Perce County spans 3 EPA Level III ecoregions — Columbia Plateau (41%), Northern Rockies (32%) and Blue Mountains (27%). 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 Nez Perce County
We scored all 1,086 plants against Nez Perce County's own USDA zone 7a and its own 216-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 Idaho profile.
Is it too late to plant in Nez Perce 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 4; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 1 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 3 — 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.
Documented around Nez Perce County
- monarch butterfly2 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Nez Perce County
USGS estimates 63,700 lb of Glyphosate on Nez Perce County farmland in 2019, its largest by weight, ahead of Bromoxynil (27,892 lb) and Metribuzin (8,800 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 Nez Perce County — and how to grow with it.
We checked the federal record across Nez Perce County — 343 documented sites across 8 of the 9 source types we track.
The most significant on record: 2 Superfund sites (none NPL-listed). 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 Nez Perce 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.
What's on the federal record near Nez Perce County
Closest first, across Nez Perce County. Listing isn't leaking, and distance isn't exposure.
- DELL LUNDER FEEDLOTCAFO · 1.5 mi
- US DOI NPS NEZ PERCE NATIONAL HIST PARKBrownfields · 2.1 mi
- 35N 04W 14DDD1Nitrate · 3.0 mi
- HEITSTUMAN RANCH COMPANY (FEEDLOT)CAFO · 3.8 mi
- 35N 03W 15DAD1Nitrate · 4.6 mi
- NIMIIPUU HEALTH SERVICE LAPWAIBrownfields · 4.9 mi
- Nez Perce County Road Dept.Underground Storage Tanks · 5.0 mi
- Culdesac School OfficeUnderground Storage Tanks · 5.1 mi
- BOYER LAND AND CATTLECAFO · 5.4 mi
- MCINTOSH & SONSUnderground Storage Tanks · 5.4 mi
- 35N 04W 02ABD1Nitrate · 5.5 mi
- VAN BUREN, DONALD - DONALD VAN BUREN FEEDLOTCAFO · 6.0 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Nez Perce 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 Nez Perce County.
Total Sites
343
across Nez Perce County
Risk Level
Elevated
Highest-severity
2 Superfund sites (none NPL-listed)
Severity Distribution
across Nez Perce County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Nez Perce County, CAFO runs higher than the national average — 11 sites across Nez Perce County. That's not a problem with your land — it's information about it.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Check your specific parcel in Nez Perce 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 Nez Perce County average
Your land is one point inside Nez Perce County
Everything above resolves to Nez Perce County as a whole — one PHZM band and one county frost record, read across 543K 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 Nez Perce County Average
Nez Perce County Average
- ●USDA Zones 7a, averaged across Nez Perce County
- ●One soil character for all of Nez Perce County
- ●Frost dates read at Nez Perce County's scale: Apr 1 to Nov 3
YOUR Parcel
- ✓Your exact zone, not Nez Perce County's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Nez Perce County
Pull a site-specific report for your exact address in Nez Perce County, Idaho — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Nez Perce County averages can't show:
We read public map data around Nez Perce County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Nez Perce County average
How we know this about Nez Perce 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 Nez Perce County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Nez Perce County
When does frost risk typically end in Nez Perce County?
The last hard freeze (28°F) in Nez Perce County typically lands around Apr 1, 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 22.
How long is the growing season in Nez Perce County?
Measured between 28°F hard freezes, Nez Perce County sees about 216 frost-free days — roughly Apr 1 through Nov 3, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 22 to Oct 20, about 181 days.
Is the soil safe to grow vegetables in Nez Perce County?
The federal record around Nez Perce County is a meaningful one — 343 documented sites, mostly Underground Storage Tanks entries (168), the nearest CAFO record about 1.5 miles out — 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.
Everything above is measured at Nez Perce County's scale — its 7a band and its 216-day season. Your yard writes its own version of Nez Perce 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 Idaho's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Nez Perce County’s own scale
9 of the readings below were taken at Nez Perce County's own scale — its own ~216-day span between 28°F freezes, the 3 most extensive soil series mapped here and 343 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Nez Perce County's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Nez Perce County's own 28°F hard-freeze dates and its ~216-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Nez Perce CountyUSDA NRCS SSURGO
- 343 documented contamination sites inside the county boundary, distance-sorted from its center — the closest CAFO record about 1.5 miles outFederal environmental registers
- Nez Perce County's boundary and the 542,925 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~216-day seasonGrowable Ground crop-matching engine
- The 3 ecoregions Nez Perce County spans, Columbia Plateau the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Nez Perce County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Nez Perce County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every Idaho grower plans around — written at state scale, so they stay on the state guidefrom Idaho
What this page can’t tell you
- How the season shifts across Nez Perce County — the ~216 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 Nez Perce County's 542,925 acreswhy one lot differs from the next →
- Which of those 343 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 Nez Perce Countyread your own land →