Lewiston, Idaho, sits in USDA hardiness zone 7b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
The conditions favor cabbage, prickly pear, california poppy, and collard greens, among others — though every individual site edits that list with its own soil, sun, and drainage.
Even in Lewiston, no two yards are alike.
A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single Lewiston lot. 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 Lewiston — soil, climate, flood, and parcel records. How we handle your address.
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Lewiston — the short answer
Lewiston, Idaho: USDA zone 7b, about 236 days between hard freezes, across 11K acres of city.
- USDA zone
- 7b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Mar 17
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 8
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~236
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 11K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are this town’s own 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 7b is Lewiston's average, not your lot's — a low corner or a tree line moves it. Against Lewiston's 236-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Lewiston
Each reading below is measured for Lewiston itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredLewiston runs about 236 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
MeasuredLewiston sits in USDA hardiness zone 7b.
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 Lewiston is in
Lewiston sits in the Columbia Plateau — EPA Level III, inside the wider North American Deserts. That is read at Lewiston's own centroid rather than borrowed from Nez Perce County.
What Grows in Lewiston
Every plant below cleared Lewiston's own zone 7b and its 236-day season. Each card opens that plant's Idaho profile. How we score.
Is it too late to plant in Lewiston?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Feb 17; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Mar 17 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 8 — long-season crops need about 90 days of runway, quick greens only 30. There is slack in a calendar like this — late plantings, second rounds of favorites, and a fall bench that keeps beds working.
What's on the federal record near Lewiston
Closest first, within ~10 miles of Lewiston. Listing isn't leaking, and distance isn't exposure.
- TESORO WEST COAST CO MIRASTAR #62025Underground Storage Tanks · 750 ft
- KRLC STUDIOUnderground Storage Tanks · 850 ft
- HOFFMANN FISKE & WYATTUnderground Storage Tanks · 1100 ft
- MOUNTAIN MART EXXONUnderground Storage Tanks · 1100 ft
- Stinker #34Underground Storage Tanks · 1600 ft
- HOME DEPOT STORE #1808Brownfields · 1600 ft
- Safeway Fuel #2641Underground Storage Tanks · 1700 ft
- SCHWEITZER ENGINEERING LABORATORIESToxics Release Inventory · 1900 ft
- SCHWEITZER ENGINEERING LABORATORIESBrownfields · 1900 ft
- COSMOPROF #8752Brownfields · 2000 ft
- LEWISTON MERCURY SPILLSuperfund · 2100 ft
- Trautman EstateUnderground Storage Tanks · 2100 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Lewiston'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 Lewiston.
Total Sites
343
within ~10 miles of Lewiston
Risk Level
Elevated
Highest-severity
2 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Lewiston
Severity Distribution
within ~10 miles of Lewiston
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Lewiston, two things run higher than the national average within ~10 miles of Lewiston — CAFO (5 sites) and Underground Storage Tanks (220 sites). That's not a problem with your land — it's information about it.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Lewiston
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 Lewiston average
Your land is one point inside Lewiston
Everything above resolves to Lewiston as a whole — one PHZM band and one 28°F frost record, read across 11K 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 city 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 local average.
Your Lot vs the Lewiston Average
Lewiston Average
- ●USDA Zones 7b, averaged across Lewiston
- ●One soil character for all of Lewiston
- ●Frost dates read at Lewiston's scale: Mar 17 to Nov 8
YOUR Parcel
- ✓Your exact zone, not Lewiston's 7b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Lewiston
Pull a site-specific report for your exact address in Lewiston, Idaho — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Lewiston averages can't show:
We read public map data around Lewiston — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Lewiston average
How we know this about Lewiston
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Lewiston’s own record; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at city grain anywhere on this page — there is no city-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about Lewiston
When does frost risk typically end in Lewiston?
The last hard freeze (28°F) in Lewiston typically lands around Mar 17, 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 7.
When is the first frost in Lewiston?
The first hard freeze (28°F) in Lewiston typically arrives around Nov 8, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 25, so the watching starts about Oct 9 — about 236 days after the spring freeze cleared.
How long is the growing season in Lewiston?
Measured between 28°F hard freezes, Lewiston sees about 236 frost-free days — roughly Mar 17 through Nov 8, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 7 to Oct 25, about 201 days.
Is the soil safe to grow vegetables in Lewiston?
The federal record around Lewiston is a meaningful one — 343 documented sites, mostly Underground Storage Tanks entries (220), the nearest Underground Storage Tanks record about 0.1 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.
How do I protect my plants from frost in Lewiston?
From about Oct 9 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Nov 8 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Nov 8. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Lewiston's scale — its 7b band and its 236-day season. Your yard writes its own version of Lewiston's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at Lewiston’s own scale
6 of the readings below were taken at Lewiston's own scale — its own ~236-day season between 28°F freezes, the 11,230 acres it covers and 343 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Lewiston's own USDA hardiness band, zones 7bUSDA PHZM 2023
- Lewiston's own 28°F hard-freeze dates, about Mar 17 and Nov 8 and the ~236-day span between themNOAA 1991–2020 Climate Normals
- 343 documented contamination sites on the federal record near Lewiston, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Lewiston's boundary and the 11,230 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7b and a ~236-day seasonGrowable Ground crop-matching engine
- The ecoregion at Lewiston's own centroid, the Columbia PlateauUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Lewiston's 11,230 acres read through its county's SSURGO summaryfrom Nez Perce County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Nez Perce County
- The growing challenges every Idaho grower plans around — written at state scale, so they stay on the state guidefrom Idaho
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Nez Perce County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Lewiston's 11,230 acreswhy one lot differs from the next →
- Which side of Lewiston you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 11,230 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.1 miles out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any Lewiston-wide figureread your own land →
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