Twin Falls, Idaho, sits in USDA hardiness zone 6b — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Well-matched crops include cabbage, blackberry, california poppy, and collard greens, and the gap between "grows in the area" and "grows in your yard" is closed by soil, sun, and drainage.
Even in Twin Falls, 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 Twin Falls 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 Twin Falls — soil, climate, flood, and parcel records. How we handle your address.
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Twin Falls — the short answer
Twin Falls, Idaho: USDA zone 6b, about 190 days between hard freezes, across 13K acres of city.
- USDA zone
- 6b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 17
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 24
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~190
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 13K 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 6b is Twin Falls's average, not your lot's — a low corner or a tree line moves it. Against Twin Falls's 190-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Twin Falls
Each reading below is measured for Twin Falls itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredTwin Falls runs about 190 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
MeasuredTwin Falls sits in USDA hardiness zone 6b.
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 Twin Falls is in
Twin Falls sits in the Snake River Plain — EPA Level III, inside the wider North American Deserts. That is read at Twin Falls's own centroid, and it is not what its county reads: Twin Falls County is mostly Northern Basin and Range. The wider page above you is answering a different question about different ground.
What Grows in Twin Falls
Every plant below cleared Twin Falls's own zone 6b and its 190-day season. Each card opens that plant's Idaho profile. How we score.
Is it too late to plant in Twin Falls?
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 20; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 17 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 24 — long-season crops need about 90 days of runway, quick greens only 30. As the window narrows, the plantings just get faster — fall brassicas, then greens, then garlic to finish.
What's on the federal record near Twin Falls
Closest first, within ~10 miles of Twin Falls. Listing isn't leaking, and distance isn't exposure.
- JIM'S 66 SERVICEUnderground Storage Tanks · 350 ft
- ALBERTSONS 4139Brownfields · 600 ft
- IDAHO POWER CO (5)Underground Storage Tanks · 900 ft
- STAKER PARSON COMPANIES DBA IDAHO MATERIALS & CONSTRUCTIONToxics Release Inventory · 900 ft
- OASIS STOP N GO #3Underground Storage Tanks · 900 ft
- ABSOLUTELY FLOWERSUnderground Storage Tanks · 1000 ft
- MR GAS #3Underground Storage Tanks · 1200 ft
- WALGREENS STORE #7277Brownfields · 1200 ft
- AT&T Communications Twin Falls ""J""Underground Storage Tanks · 1500 ft
- TWIN FALLS CLINIC ASSOCIATIONUnderground Storage Tanks · 1900 ft
- WAGNER TRANSPORTATIONUnderground Storage Tanks · 2300 ft
- Old Twin Falls County CourthouseUnderground Storage Tanks · 2400 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Twin Falls'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 Twin Falls.
Total Sites
585
within ~10 miles of Twin Falls
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Twin Falls
Severity Distribution
within ~10 miles of Twin Falls
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Twin Falls, two things run higher than the national average within ~10 miles of Twin Falls — CAFO (15 sites) and Nitrate (190 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Twin Falls
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 Twin Falls average
Your land is one point inside Twin Falls
Everything above resolves to Twin Falls as a whole — one PHZM band and one 28°F frost record, read across 13K 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 Twin Falls Average
Twin Falls Average
- ●USDA Zones 6b, averaged across Twin Falls
- ●One soil character for all of Twin Falls
- ●Frost dates read at Twin Falls's scale: Apr 17 to Oct 24
YOUR Parcel
- ✓Your exact zone, not Twin Falls's 6b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Twin Falls
Pull a site-specific report for your exact address in Twin Falls, Idaho — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Twin Falls averages can't show:
We read public map data around Twin Falls — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Twin Falls average
How we know this about Twin Falls
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 Twin Falls’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 Twin Falls
When does frost risk typically end in Twin Falls?
The last hard freeze (28°F) in Twin Falls typically lands around Apr 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 May 8.
When is the first frost in Twin Falls?
The first hard freeze (28°F) in Twin Falls typically arrives around Oct 24, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 10, so the watching starts about Sep 24 — about 190 days after the spring freeze cleared.
How long is the growing season in Twin Falls?
Measured between 28°F hard freezes, Twin Falls sees about 190 frost-free days — roughly Apr 17 through Oct 24, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 8 to Oct 10, about 155 days.
Is the soil safe to grow vegetables in Twin Falls?
The federal record around Twin Falls is a meaningful one — 585 documented sites, mostly Underground Storage Tanks entries (286), the nearest Underground Storage Tanks record under a tenth of a mile 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 Twin Falls?
From about Sep 24 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 24 (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 24. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Twin Falls's scale — its 6b band and its 190-day season. Your yard writes its own version of Twin Falls'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 Twin Falls’s own scale
6 of the readings below were taken at Twin Falls's own scale — its own ~190-day season between 28°F freezes, the 12,713 acres it covers and 585 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Twin Falls's own USDA hardiness band, zones 6bUSDA PHZM 2023
- Twin Falls's own 28°F hard-freeze dates, about Apr 17 and Oct 24 and the ~190-day span between themNOAA 1991–2020 Climate Normals
- 585 documented contamination sites on the federal record near Twin Falls, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Twin Falls's boundary and the 12,713 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6b and a ~190-day seasonGrowable Ground crop-matching engine
- Twin Falls sits in the Snake River Plain — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Twin Falls's 12,713 acres read through its county's SSURGO summaryfrom Twin Falls County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Twin Falls 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 Twin Falls County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Twin Falls's 12,713 acreswhy one lot differs from the next →
- Which side of Twin Falls you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 12,713 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 Twin Falls-wide figureread your own land →
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