Clifton, Idaho, sits in USDA hardiness zone 6a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
The conditions favor cabbage, blackberry, california poppy, and collard greens, among others — though every individual site edits that list with its own soil, sun, and drainage.
Even in Clifton, 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 Clifton 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 Clifton — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Clifton — the short answer
Clifton, Idaho: USDA zone 6a, about 165 days between hard freezes, across 1K acres of city.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 29
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 11
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~165
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 1K 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 6a is Clifton's average, not your lot's — a low corner or a tree line moves it. Against Clifton's 165-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Clifton
Each reading below is measured for Clifton itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredClifton runs about 165 days between hard freezes — a moderate growing season.
There is room for the full run of cool-season crops plus a warm-season main crop, but the calendar is tight enough that a late spring or early fall frost still decides how much finishes.
Time warm-season transplants to your last hard freeze, and a few weeks of season extension turns a near-miss harvest into a sure one.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredClifton sits in USDA hardiness zone 6a.
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 Clifton is in
Clifton sits in the Central Basin and Range — EPA Level III, inside the wider North American Deserts. That is read at Clifton's own centroid, and it is not what its county reads: Franklin County is mostly Northern Basin and Range. The wider page above you is answering a different question about different ground.
What Grows in Clifton
Every plant below cleared Clifton's own zone 6a and its 165-day season. Each card opens that plant's Idaho profile. How we score.
Is it too late to plant in Clifton?
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 Apr 1; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 29 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 11 — long-season crops need about 90 days of runway, quick greens only 30. The tail of the season still works: sixty-day crops into late summer, quick greens after, garlic last of all.
What's on the federal record near Clifton
Closest first, within ~10 miles of Clifton. Listing isn't leaking, and distance isn't exposure.
- PAPA JAYS INCUnderground Storage Tanks · 300 ft
- 14S 38E 22BDD1Nitrate · 1700 ft
- 14S 38E 22CCB1Nitrate · 2000 ft
- 14S 38E 22ABA1Nitrate · 0.8 mi
- 14S 38E 26ADC1Nitrate · 1.6 mi
- Lucky Baker ProspectMining · 1.9 mi
- 15S/18E-02BCB1Nitrate · 2.7 mi
- 15S 38E 11BBC1Nitrate · 3.5 mi
- 14S 39E 08ADA1Nitrate · 5.0 mi
- DAYTON SECTIONUnderground Storage Tanks · 5.1 mi
- 15S 38E 23BBD1Nitrate · 5.4 mi
- LUNDAHL IRONWORKSBrownfields · 5.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Clifton'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 Clifton.
Total Sites
80
within ~10 miles of Clifton
Risk Level
Moderate
Highest-severity
1 Toxics Release Inventory facility
Sources Checked
within ~10 miles of Clifton
Severity Distribution
within ~10 miles of Clifton
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Clifton, Nitrate runs higher than the national average — 40 sites within ~10 miles of Clifton. That's not a problem with your land — it's information about it.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Clifton
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 Clifton average
Your land is one point inside Clifton
Everything above resolves to Clifton as a whole — one PHZM band and one 28°F frost record, read across 1K 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 Clifton Average
Clifton Average
- ●USDA Zones 6a, averaged across Clifton
- ●One soil character for all of Clifton
- ●Frost dates read at Clifton's scale: Apr 29 to Oct 11
YOUR Parcel
- ✓Your exact zone, not Clifton's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Clifton
Pull a site-specific report for your exact address in Clifton, Idaho — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Clifton averages can't show:
We read public map data around Clifton — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Clifton average
How we know this about Clifton
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 Clifton’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 Clifton
When does frost risk typically end in Clifton?
The last hard freeze (28°F) in Clifton typically lands around Apr 29, 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 May 20.
When is the first frost in Clifton?
The first hard freeze (28°F) in Clifton typically arrives around Oct 11, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 27, so the watching starts about Sep 11 — about 165 days after the spring freeze cleared.
How long is the growing season in Clifton?
Measured between 28°F hard freezes, Clifton sees about 165 frost-free days — roughly Apr 29 through Oct 11, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 20 to Sep 27, about 130 days.
Is the soil safe to grow vegetables in Clifton?
The federal record around Clifton shows 80 documented sites, mostly Nitrate entries (40), the nearest Underground Storage Tanks record under a tenth of a mile out — a typical footprint for a growing area, and proximity to a documented site is information, not a diagnosis of any one yard. It's worth seeing which recorded sites sit closest to where you grow, and testing the soil before new food beds near any of them.
How do I protect my plants from frost in Clifton?
From about Sep 11 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 Oct 11 (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 Oct 11. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Clifton's scale — its 6a band and its 165-day season. Your yard writes its own version of Clifton'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 Clifton’s own scale
6 of the readings below were taken at Clifton's own scale — its own ~165-day season between 28°F freezes, the 1,471 acres it covers and 80 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Clifton's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Clifton's own 28°F hard-freeze dates, about Apr 29 and Oct 11 and the ~165-day span between themNOAA 1991–2020 Climate Normals
- 80 documented contamination sites on the federal record near Clifton, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Clifton's boundary and the 1,471 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~165-day seasonGrowable Ground crop-matching engine
- Clifton sits in the Central Basin and Range — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Clifton's 1,471 acres read through its county's SSURGO summaryfrom Franklin County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Franklin 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 Franklin County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Clifton's 1,471 acreswhy one lot differs from the next →
- Which side of Clifton you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,471 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record under a tenth of a mile 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 Clifton-wide figureread your own land →
More in Idaho
Growing region
Nearby growing guides