Boise City, 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.
The conditions favor cabbage, hazelnut, california poppy, and collard greens, among others — though every individual site edits that list with its own soil, sun, and drainage.
Even in Boise City, 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 Boise City 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 Boise City — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Boise City — the short answer
Boise City, Idaho: USDA zone 7a, about 212 days between hard freezes, across 55K acres of city.
- USDA zone
- 7a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 4
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 2
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~212
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 55K 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 7a is Boise City's average, not your lot's — a low corner or a tree line moves it. Against Boise City's 212-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Boise City
Each reading below is measured for Boise City itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredBoise City runs about 212 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
MeasuredBoise City 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 Boise City is in
Boise City sits in the Snake River Plain — EPA Level III, inside the wider North American Deserts. That is read at Boise City's own centroid rather than borrowed from Ada County.
What Grows in Boise City
Every plant below cleared Boise City's own zone 7a and its 212-day season. Each card opens that plant's Idaho profile. How we score.
Is it too late to plant in Boise City?
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 7; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 4 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 2 — 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 Boise City
Closest first, within ~10 miles of Boise City. Listing isn't leaking, and distance isn't exposure.
- TREASURE VALLEY REPAIRUnderground Storage Tanks · 550 ft
- JACKSONS FOOD STORE #43Underground Storage Tanks · 650 ft
- 03N 02E 16BBD1Nitrate · 800 ft
- 03N 02E 16BBC1Nitrate · 1000 ft
- JACKSONS FOOD STORE #31Underground Storage Tanks · 1000 ft
- 03N 02E 16BBC2-DESTROYEDNitrate · 1100 ft
- LIKE NU CARWASHES INC #13Underground Storage Tanks · 1700 ft
- 03N 02E 09CCDA1Nitrate · 2100 ft
- TOOL SHED NO. 6207Underground Storage Tanks · 2200 ft
- 03N 02E 16DBB1Nitrate · 2200 ft
- A COMPANY INCUnderground Storage Tanks · 2300 ft
- 03N 02E 17DABC1Nitrate · 0.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Boise City'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 Boise City.
Total Sites
2,226
within ~10 miles of Boise City
Risk Level
High
Highest-severity
7 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Boise City
Severity Distribution
within ~10 miles of Boise City
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Boise City, Nitrate runs higher than the national average — 1,106 sites within ~10 miles of Boise City. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around 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 Boise City
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 Boise City average
Your land is one point inside Boise City
Everything above resolves to Boise City as a whole — one PHZM band and one 28°F frost record, read across 55K 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 Boise City Average
Boise City Average
- ●USDA Zones 7a, averaged across Boise City
- ●One soil character for all of Boise City
- ●Frost dates read at Boise City's scale: Apr 4 to Nov 2
YOUR Parcel
- ✓Your exact zone, not Boise City's 7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Boise City
Pull a site-specific report for your exact address in Boise City, Idaho — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Boise City averages can't show:
We read public map data around Boise City — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Boise City average
How we know this about Boise City
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 Boise City’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 Boise City
When does frost risk typically end in Boise City?
The last hard freeze (28°F) in Boise City typically lands around Apr 4, 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 25.
When is the first frost in Boise City?
The first hard freeze (28°F) in Boise City typically arrives around Nov 2, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 19, so the watching starts about Oct 3 — about 212 days after the spring freeze cleared.
How long is the growing season in Boise City?
Measured between 28°F hard freezes, Boise City sees about 212 frost-free days — roughly Apr 4 through Nov 2, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 25 to Oct 19, about 177 days.
Is the soil safe to grow vegetables in Boise City?
The federal record around Boise City runs heavier than most — 2,226 documented sites, mostly Nitrate entries (1,106), the nearest Underground Storage Tanks record about 0.1 miles out — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
How do I protect my plants from frost in Boise City?
From about Oct 3 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 2 (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 2. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Boise City's scale — its 7a band and its 212-day season. Your yard writes its own version of Boise City'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 Boise City’s own scale
6 of the readings below were taken at Boise City's own scale — its own ~212-day season between 28°F freezes, the 54,500 acres it covers and 2,226 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Boise City's own USDA hardiness band, zones 7aUSDA PHZM 2023
- Boise City's own 28°F hard-freeze dates, about Apr 4 and Nov 2 and the ~212-day span between themNOAA 1991–2020 Climate Normals
- 2,226 documented contamination sites on the federal record near Boise City, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Boise City's boundary and the 54,500 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7a and a ~212-day seasonGrowable Ground crop-matching engine
- The ecoregion at Boise City's own centroid, the Snake River PlainUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Boise City's 54,500 acres read through its county's SSURGO summaryfrom Ada County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Ada 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 Ada County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Boise City's 54,500 acreswhy one lot differs from the next →
- Which side of Boise City you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 54,500 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 Boise City-wide figureread your own land →