Coolin, Idaho, sits in USDA hardiness zone 6a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
A short list that earns its place here — cabbage, blackberry, california poppy, and collard greens — with any one site's soil, sun, and drainage making the final cut.
Even in Coolin, 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 Coolin 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 Coolin — soil, climate, flood, and parcel records. How we handle your address.
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Coolin — the short answer
Coolin, Idaho: USDA zone 6a, about 146 days between hard freezes, across 325 acres of town.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 7
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Sep 30
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~146
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 325 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 6a is Coolin's average, not your lot's — a low corner or a tree line moves it. Against Coolin's 146-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Coolin
Each reading below is measured for Coolin itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredCoolin runs about 146 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
MeasuredCoolin sits in USDA hardiness zone 6a.
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 Coolin is in
Coolin sits in the Northern Rockies — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at Coolin's own centroid rather than borrowed from Bonner County.
What Grows in Coolin
Every plant below cleared Coolin's own zone 6a and its 146-day season. Each card opens that plant's Idaho profile. How we score.
Is it too late to plant in Coolin?
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 9; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 7 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 30 — long-season crops need about 90 days of runway, quick greens only 30. Even here the calendar’s edges hold value: thirty-day greens late in the window, then garlic and a rested bed for spring.
What's on the federal record near Coolin
Closest first, within ~10 miles of Coolin. Listing isn't leaking, and distance isn't exposure.
- PRIEST LAKE AREA OFFICEUnderground Storage Tanks · 100 ft
- Moose Knuckle TavernUnderground Storage Tanks · 750 ft
- 59N 04W 15BBA1Nitrate · 1600 ft
- 59N 04W 10CAB1Nitrate · 1700 ft
- BISHOP MARINAUnderground Storage Tanks · 1900 ft
- LEONARD PAUL STOREUnderground Storage Tanks · 1900 ft
- IdahoMining · 2.8 mi
- BLUE DIAMOND MARINA CORPUnderground Storage Tanks · 2.9 mi
- CAVANAUGH'S AT PRIEST LAKEUnderground Storage Tanks · 3.3 mi
- Sundance MountainMining · 3.4 mi
- Soldier Creek ProspectsMining · 3.4 mi
- Binarch Cr. Mining Co. ProspectMining · 3.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Coolin'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 Coolin.
Sources Checked
within ~10 miles of Coolin
Severity Distribution
within ~10 miles of Coolin
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Coolin, Mining runs higher than the national average — 21 sites within ~10 miles of Coolin. 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.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Check your specific parcel in Coolin
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 Coolin average
Your land is one point inside Coolin
Everything above resolves to Coolin as a whole — one PHZM band and one 28°F frost record, read across 325 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 town 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 Coolin Average
Coolin Average
- ●USDA Zones 6a, averaged across Coolin
- ●One soil character for all of Coolin
- ●Frost dates read at Coolin's scale: May 7 to Sep 30
YOUR Parcel
- ✓Your exact zone, not Coolin's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Coolin
Pull a site-specific report for your exact address in Coolin, Idaho — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Coolin averages can't show:
We read public map data around Coolin — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Coolin average
How we know this about Coolin
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Coolin’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 town grain anywhere on this page — there is no town-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 Coolin
When does frost risk typically end in Coolin?
The last hard freeze (28°F) in Coolin typically lands around May 7, 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 28.
When is the first frost in Coolin?
The first hard freeze (28°F) in Coolin typically arrives around Sep 30, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 16, so the watching starts about Aug 31 — about 146 days after the spring freeze cleared.
How long is the growing season in Coolin?
Measured between 28°F hard freezes, Coolin sees about 146 frost-free days — roughly May 7 through Sep 30, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 28 to Sep 16, about 111 days.
Is the soil safe to grow vegetables in Coolin?
The federal record around Coolin is a meaningful one — 50 documented sites, mostly Mining entries (21), 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 gardeners stretch the season in Coolin?
With about 146 frost-free days between hard freezes, Coolin 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 174 to 202 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 7 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Coolin's scale — its 6a band and its 146-day season. Your yard writes its own version of Coolin'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 Coolin’s own scale
6 of the readings below were taken at Coolin's own scale — its own ~146-day season between 28°F freezes, the 325 acres it covers and 50 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Coolin's own USDA hardiness band, zones 6aUSDA PHZM 2023
- Coolin's own 28°F hard-freeze dates, about May 7 and Sep 30 and the ~146-day span between themNOAA 1991–2020 Climate Normals
- 50 documented contamination sites on the federal record near Coolin, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Coolin's boundary and the 325 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~146-day seasonGrowable Ground crop-matching engine
- The ecoregion at Coolin's own centroid, the Northern RockiesUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Coolin's 325 acres read through its county's SSURGO summaryfrom Bonner County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Bonner 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 Bonner County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Coolin's 325 acreswhy one lot differs from the next →
- Which side of Coolin you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 325 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 Coolin-wide figureread your own land →
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