Canyon County, in Idaho, sits in USDA hardiness zone 7a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
A short list that earns its place here — cabbage, pawpaw, california poppy, and collard greens — with any one site's soil, sun, and drainage making the final cut.
Canyon County lies within the Treasure 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
Canyon County holds more than one microclimate.
Soils and elevations shift across Canyon 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 Canyon County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Canyon County — the short answer
Canyon County, Idaho: USDA zone 7a, about 205 days between hard freezes, across 376K acres.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 5
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 27
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~205
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 376K 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 Canyon County's average, not your lot's — a low corner or a tree line moves it. Against Canyon County's 205-day season, see what your own ground reads.
Heat in Canyon County
Across a year, Canyon County accumulates about 2,718 growing degree days above 50°F, about 1,227 more than the middle Idaho county — ahead of 42 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 Canyon County
Across Canyon County, the ground is predominantly Aridisols, where Power, Scism, and Elijah are the most extensive named soil series. The soil is generally well drained with a silt loam surface. Topsoil pH runs about 7.2–7.9, slightly alkaline. Rainfall drains through hydrologic group C soils.
Soil order
Aridisols
Drainage
Well drained
Hydric soils
1%
Soil still varies lot by lot — soil types explained.
How the ground varies across Canyon County
The USDA soil survey maps 75% of Canyon County as well drained — but another 20% drains differently: 10% somewhat poorly drained, 5% poorly drained.
Power is the most extensive named soil at 12% of mapped acres, then Scism (9%) and Elijah (7%).
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 Canyon County
Each reading below is measured for Canyon 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 Canyon 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 Canyon County runs about pH 7.2–7.9, on the alkaline side.
Many vegetables cope, but acid-lovers like blueberries struggle, and iron and manganese lock up above about pH 7.5 — leaves yellow between the veins even in rich soil.
Elemental sulfur and generous organic matter lower pH slowly for the beds that need it; test first so you add only what the soil actually calls for.
USDA NRCS SSURGO
Season length
MeasuredCanyon County runs about 205 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
MeasuredCanyon 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 Canyon County is in
Canyon County sits in the Snake River Plain — EPA Level III, inside the wider North American Deserts. One consistent ecological setting across the whole county.
What Grows in Canyon County
We scored all 1,086 plants against Canyon County's own USDA zone 7a and its own 205-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 Canyon 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 8; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 5 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 27 — 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 Canyon County
- monarch butterfly1 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Canyon County
USGS estimates 75,788 lb of Glyphosate on Canyon County farmland in 2019, its largest by weight, ahead of Methomyl (13,187 lb) and Bromoxynil (8,822 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 Canyon County — and how to grow with it.
We checked the federal record across Canyon County — 1,694 documented sites across 7 of the 9 source types we track.
The most significant on record: 4 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 Canyon 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 Canyon County
Closest first, across Canyon County. Listing isn't leaking, and distance isn't exposure.
- 03N 03W 04BADD1Nitrate · 2100 ft
- 03N 03W 05DDCB1Nitrate · 0.6 mi
- 03N 03W 04BAAA1Nitrate · 0.6 mi
- 03N 03W 09BAB1Nitrate · 0.6 mi
- 03N 03W 04DACC1Nitrate · 0.7 mi
- 03N 03W 09BBCD1Nitrate · 0.7 mi
- 03N 03W 08AADD1Nitrate · 0.8 mi
- WALGREENS STORE #11541Brownfields · 0.9 mi
- 03N 03W 03BBC1Nitrate · 1.0 mi
- SW ID RESEARCH & EXTENSION CENTERUnderground Storage Tanks · 1.0 mi
- MAVERIK COUNTRY STORE #298Underground Storage Tanks · 1.0 mi
- 03N 03W 09CBC1Nitrate · 1.2 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Canyon 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 Canyon County.
Total Sites
1,694
across Canyon County
Risk Level
Elevated
Highest-severity
4 Superfund sites (none NPL-listed)
Severity Distribution
across Canyon County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Canyon County, two things run higher than the national average across Canyon County — Nitrate (1,140 sites) and CAFO (29 sites). 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.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Check your specific parcel in Canyon 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 Canyon County average
Your land is one point inside Canyon County
Everything above resolves to Canyon County as a whole — one PHZM band and one county frost record, read across 376K 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 Canyon County Average
Canyon County Average
- ●USDA Zones 7a, averaged across Canyon County
- ●One soil character for all of Canyon County
- ●Frost dates read at Canyon County's scale: Apr 5 to Oct 27
YOUR Parcel
- ✓Your exact zone, not Canyon County's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Canyon County
Pull a site-specific report for your exact address in Canyon County, Idaho — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Canyon County averages can't show:
We read public map data around Canyon County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Canyon County average
How we know this about Canyon 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 Canyon County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Canyon County
When does frost risk typically end in Canyon County?
The last hard freeze (28°F) in Canyon County typically lands around Apr 5, 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 26.
How long is the growing season in Canyon County?
Measured between 28°F hard freezes, Canyon County sees about 205 frost-free days — roughly Apr 5 through Oct 27, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 26 to Oct 13, about 170 days.
Is the soil safe to grow vegetables in Canyon County?
The federal record around Canyon County is a meaningful one — 1,694 documented sites, mostly Nitrate entries (1,140), the nearest Nitrate record about 0.4 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 Canyon County's scale — its 7a band and its 205-day season. Your yard writes its own version of Canyon 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 Canyon County’s own scale
9 of the readings below were taken at Canyon County's own scale — its own ~205-day span between 28°F freezes, the 3 most extensive soil series mapped here and 1,694 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Canyon County's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Canyon County's own 28°F hard-freeze dates and its ~205-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Canyon CountyUSDA NRCS SSURGO
- 1,694 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Nitrate record about 0.4 miles outFederal environmental registers
- Canyon County's boundary and the 375,711 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~205-day seasonGrowable Ground crop-matching engine
- Canyon County sitting wholly inside the Snake River PlainUS EPA Level III Ecoregions
- Open occurrence records documented in Canyon County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Canyon 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 Canyon County — the ~205 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 Canyon County's 375,711 acreswhy one lot differs from the next →
- Which of those 1,694 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 Canyon Countyread your own land →