Osburn, Idaho, sits in USDA hardiness zone 6b — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Among the crops suited to this profile: cabbage, blackberry, california poppy, and collard greens. The site-level story — soil, sun, drainage — decides the rest.
Even in Osburn, 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 Osburn 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 Osburn — soil, climate, flood, and parcel records. How we handle your address.
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Osburn — the short answer
Osburn, Idaho: USDA zone 6b, about 174 days between hard freezes, across 843 acres of city.
- USDA zone
- 6b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 25
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 16
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~174
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 843 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 Osburn's average, not your lot's — a low corner or a tree line moves it. Against Osburn's 174-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Osburn
Each reading below is measured for Osburn itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredOsburn runs about 174 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
MeasuredOsburn 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 Osburn is in
Osburn sits in the Northern Rockies — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at Osburn's own centroid rather than borrowed from Shoshone County.
What Grows in Osburn
Every plant below cleared Osburn's own zone 6b and its 174-day season. Each card opens that plant's Idaho profile. How we score.
Is it too late to plant in Osburn?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Mar 28; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 25 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 16 — 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 Osburn
Closest first, within ~10 miles of Osburn. Listing isn't leaking, and distance isn't exposure.
- OSBURN GAS MARTUnderground Storage Tanks · 300 ft
- MARLIN M. PALMERUnderground Storage Tanks · 350 ft
- CALLAHAN MINING CORPUnderground Storage Tanks · 650 ft
- COEUR MINEUnderground Storage Tanks · 650 ft
- COEUR D'ALENE MINEUnderground Storage Tanks · 750 ft
- GRAVLEY FURNACE INCUnderground Storage Tanks · 850 ft
- MCGILLIVRAY ENVIRONMENTALBrownfields · 1700 ft
- Coeur D'Alene DistrictMining · 2100 ft
- CITY OF OSBURNUnderground Storage Tanks · 0.5 mi
- St. Elmo MineMining · 0.5 mi
- St. Elmo ProspectMining · 0.5 mi
- 48N 03E 13ACB1Nitrate · 0.8 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Osburn'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 Osburn.
Sources Checked
within ~10 miles of Osburn
Severity Distribution
within ~10 miles of Osburn
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Osburn, two things run higher than the national average within ~10 miles of Osburn — Mining (428 sites) and Nitrate (324 sites). That's not a problem with your land — it's information about it.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Osburn
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 Osburn average
Your land is one point inside Osburn
Everything above resolves to Osburn as a whole — one PHZM band and one 28°F frost record, read across 843 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 Osburn Average
Osburn Average
- ●USDA Zones 6b, averaged across Osburn
- ●One soil character for all of Osburn
- ●Frost dates read at Osburn's scale: Apr 25 to Oct 16
YOUR Parcel
- ✓Your exact zone, not Osburn's 6b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Osburn
Pull a site-specific report for your exact address in Osburn, Idaho — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Osburn averages can't show:
We read public map data around Osburn — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Osburn average
How we know this about Osburn
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 Osburn’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 Osburn
When does frost risk typically end in Osburn?
The last hard freeze (28°F) in Osburn typically lands around Apr 25, 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 16.
When is the first frost in Osburn?
The first hard freeze (28°F) in Osburn typically arrives around Oct 16, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 2, so the watching starts about Sep 16 — about 174 days after the spring freeze cleared.
How long is the growing season in Osburn?
Measured between 28°F hard freezes, Osburn sees about 174 frost-free days — roughly Apr 25 through Oct 16, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 16 to Oct 2, about 139 days.
Is the soil safe to grow vegetables in Osburn?
The federal record around Osburn runs heavier than most — 842 documented sites, mostly Mining entries (428), the nearest Underground Storage Tanks record under a tenth of a mile 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 Osburn?
From about Sep 16 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 16 (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 16. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Osburn's scale — its 6b band and its 174-day season. Your yard writes its own version of Osburn'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 Osburn’s own scale
6 of the readings below were taken at Osburn's own scale — its own ~174-day season between 28°F freezes, the 843 acres it covers and 842 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Osburn's own USDA hardiness band, zones 6bUSDA PHZM 2023
- Osburn's own 28°F hard-freeze dates, about Apr 25 and Oct 16 and the ~174-day span between themNOAA 1991–2020 Climate Normals
- 842 documented contamination sites on the federal record near Osburn, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Osburn's boundary and the 843 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6b and a ~174-day seasonGrowable Ground crop-matching engine
- The ecoregion at Osburn's own centroid, the Northern RockiesUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Osburn's 843 acres read through its county's SSURGO summaryfrom Shoshone County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Shoshone 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 Shoshone County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Osburn's 843 acreswhy one lot differs from the next →
- Which side of Osburn you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 843 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 Osburn-wide figureread your own land →
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