Teton County, in Idaho, sits in USDA hardiness zone 5a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Well-matched crops include cabbage, cranberry, lavender, and collard greens, and the gap between "grows in the area" and "grows in your yard" is closed by soil, sun, and drainage.
Teton County lies within the Eastern Idaho (Upper Snake River Valley) and the Snake River Plain — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Teton County holds more than one microclimate.
Soils and elevations shift across Teton 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 Teton County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Teton County — the short answer
Teton County, Idaho: USDA zone 5a, about 133 days between hard freezes, across 287K acres.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 16
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Sep 26
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~133
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 287K 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 5a is Teton County's average, not your lot's — a low corner or a tree line moves it. Against Teton County's 133-day season, see what your own ground reads.
Heat in Teton County
Across a year, Teton County accumulates about 1,137 growing degree days above 50°F, about 354 fewer than the middle Idaho county — ahead of 11 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 Teton County
Across Teton County, the ground is predominantly Mollisols, where Alpine, Koffgo, and Kucera are the most extensive named soil series. The soil is generally well drained with a silt loam surface. Topsoil pH runs about 6.1–7.4, neutral. Rainfall drains through hydrologic group C soils.
Soil order
Mollisols
Drainage
Well drained
Hydric soils
11%
Soil still varies lot by lot — soil types explained.
How the ground varies across Teton County
The USDA soil survey maps 88% of Teton County as well drained — but another 11% drains differently: 7% poorly drained, 3% very poorly drained.
Alpine is the most extensive named soil at 11% of mapped acres, then Koffgo (9%) and Kucera (8%).
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 Teton County
Each reading below is measured for Teton 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 Teton 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 Teton County runs about pH 6.1–7.4, 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
MeasuredTeton County runs about 133 days between hard freezes — a short growing season.
Long-maturing crops like melons, sweet potatoes, and winter squash can run out of runway before the first hard freeze, ripening late or not at all.
Lead with fast-maturing varieties, and stretch the season on both ends with cold frames, low tunnels, or a greenhouse.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredTeton County sits in USDA hardiness zone 5a.
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 Teton County is in
Teton County spans 2 EPA Level III ecoregions — Snake River Plain (62%) and Middle Rockies (38%). 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 Teton County
We scored all 1,086 plants against Teton County's own USDA zone 5a and its own 133-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 Teton County?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Apr 18; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 16 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 26 — long-season crops need about 90 days of runway, quick greens only 30. In a season this compact, fast finishers and cold-hardy greens do the late work, and garlic tucked in before the freeze repays you next summer.
What gets applied to farmland in Teton County
USGS estimates 14,406 lb of Glyphosate on Teton County farmland in 2019, its largest by weight, ahead of 2,4-d (5,357 lb) and Bromoxynil (3,093 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 Teton County — and how to grow with it.
We checked the federal record across Teton County — 170 documented sites across 4 of the 9 source types we track.
The most significant on record: 3 mining sites. Historic and active mines that may leach heavy metals like arsenic, lead, and cadmium.
The federal record across Teton County is a modest one — a typical footprint for a growing area. Nothing here calls for alarm; it's worth knowing which recorded sites sit closest to where you grow, and each one on the map carries its type and location. If one turns out to be a near neighbor, a one-time soil test settles the question.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Teton County
Closest first, across Teton County. Listing isn't leaking, and distance isn't exposure.
- 05N 44E 23DBD1Nitrate · 1.5 mi
- 05N 44E 27ABC1Nitrate · 2.6 mi
- 05N 44E 35ABA1Nitrate · 2.7 mi
- 05N 44E 36AAD1Nitrate · 2.9 mi
- 06N 44E 36ABD1Nitrate · 3.2 mi
- 05N 44E 35DDD1Nitrate · 3.5 mi
- 06N 45E 33CCC1Nitrate · 3.6 mi
- 05N 45E 10CCB1Nitrate · 3.6 mi
- Grand View General StoreUnderground Storage Tanks · 4.4 mi
- 06N 44E 26BAA1Nitrate · 4.5 mi
- 06N 44E 23CDD1Nitrate · 4.5 mi
- 06N 45E 19DDCC1Nitrate · 4.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Teton 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 Teton County.
Sources Checked
across Teton County
Severity Distribution
across Teton County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Teton County, Nitrate runs higher than the national average — 136 sites across Teton County. 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 Teton 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 Teton County average
Your land is one point inside Teton County
Everything above resolves to Teton County as a whole — one PHZM band and one county frost record, read across 287K 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 Teton County Average
Teton County Average
- ●USDA Zones 5a, averaged across Teton County
- ●One soil character for all of Teton County
- ●Frost dates read at Teton County's scale: May 16 to Sep 26
YOUR Parcel
- ✓Your exact zone, not Teton County's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Teton County
Pull a site-specific report for your exact address in Teton County, Idaho — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Teton County averages can't show:
We read public map data around Teton County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Teton County average
How we know this about Teton 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 Teton County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Teton County
When does frost risk typically end in Teton County?
The last hard freeze (28°F) in Teton County typically lands around May 16, 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 Jun 6.
How long is the growing season in Teton County?
Measured between 28°F hard freezes, Teton County sees about 133 frost-free days — roughly May 16 through Sep 26, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 6 to Sep 12, about 98 days.
Is the soil safe to grow vegetables in Teton County?
The federal record around Teton County shows 170 documented sites, mostly Nitrate entries (136), the nearest Nitrate record about 1.5 miles 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 gardeners stretch the season in Teton County?
With about 133 frost-free days between hard freezes, Teton County rewards the classic extension moves: floating row cover buys roughly two to four extra weeks at each shoulder — on this season that is a working window nearer 161 to 189 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 16 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Teton County's scale — its 5a band and its 133-day season. Your yard writes its own version of Teton 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 Teton County’s own scale
8 of the readings below were taken at Teton County's own scale — its own ~133-day span between 28°F freezes, the 3 most extensive soil series mapped here and 170 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Teton County's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Teton County's own 28°F hard-freeze dates and its ~133-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Teton CountyUSDA NRCS SSURGO
- 170 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Nitrate record about 1.5 miles outFederal environmental registers
- Teton County's boundary and the 287,418 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~133-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Teton County spans, Snake River Plain the largestUS EPA Level III Ecoregions
- Which agricultural compounds go onto Teton 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 Teton County — the ~133 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 Teton County's 287,418 acreswhy one lot differs from the next →
- Which of those 170 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 Teton Countyread your own land →