Kobuk, Alaska, sits in USDA hardiness zone 1b — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Reliable performers under these conditions include cabbage, potato, rhubarb, and kale; what your own ground favors still comes down to its soil, sun, and drainage.
Even in Kobuk, 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 Kobuk 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 Kobuk — soil, climate, flood, and parcel records. How we handle your address.
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Kobuk — the short answer
Kobuk, Alaska: USDA zone 1b, about 127 days between hard freezes, across 10K acres of city.
- USDA zone
- 1b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 24
- Northwest Arctic Borough normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Sep 28
- Northwest Arctic Borough normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~127
- Northwest Arctic Borough normal — NOAA 1991–2020, nearest to this town
- City area
- 10K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. No 30-year normal resolves at this town’s own centroid, so the hard-freeze dates are Northwest Arctic Borough’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 1b is Kobuk's average, not your lot's — a low corner or a tree line moves it. Against Kobuk's 127-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Kobuk
Each reading below is measured for Kobuk itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsKobuk runs about 127 days between hard freezes (read from Northwest Arctic Borough, the closest normal to Kobuk) — 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
MeasuredKobuk sits in USDA hardiness zone 1b.
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
What Grows in Kobuk
Plants matched to Kobuk's USDA zones 1b, ordered by how much hardiness margin each has here — the ones with room to spare at both ends of this town's band lead. Each links to its full growing profile.
Is it too late to plant in Kobuk?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Apr 26; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 24 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 28 — 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 Kobuk
Closest first, within ~10 miles of Kobuk. Listing isn't leaking, and distance isn't exposure.
- KA01700903BABC1 001Nitrate · 1.0 mi
- Dahl CreekMining · 4.2 mi
- Upper Dahl CreekMining · 4.2 mi
- Unnamed (upper Wesley Creek area)Mining · 5.9 mi
- Wesley CreekMining · 5.9 mi
- Wesley Creek OccurrenceMining · 6.0 mi
- UnnamedMining · 6.9 mi
- Bear Cr. Mng. Co.Mining · 9.6 mi
Measured from Kobuk'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 Kobuk.
Severity Distribution
within ~10 miles of Kobuk
Highest-Severity Sites
Know Before You Grow
- •Mine waste leaches heavy metals. Test for lead, arsenic and cadmium before growing food here.
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
Check your specific parcel in Kobuk
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 Kobuk average
Your land is one point inside Kobuk
Everything above resolves to Kobuk as a whole — one PHZM band, read across 10K acres, with hard-freeze dates borrowed from Northwest Arctic Borough’s record because no 30-year normal resolves at this city’s own centroid. 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 Kobuk Average
Kobuk Average
- ●USDA Zones 1b, averaged across Kobuk
- ●One soil character for all of Kobuk
- ●Frost dates read at Kobuk's scale: May 24 to Sep 28
YOUR Parcel
- ✓Your exact zone, not Kobuk's 1b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Kobuk
Pull a site-specific report for your exact address in Kobuk, Alaska — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Kobuk averages can't show:
We read public map data around Kobuk — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Kobuk average
How we know this about Kobuk
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 Northwest Arctic Borough’s record, because none resolves here; 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 Kobuk
When does frost risk typically end in Kobuk?
The last hard freeze (28°F) in Kobuk typically lands around May 24, 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 14.
When is the first frost in Kobuk?
The first hard freeze (28°F) in Kobuk typically arrives around Sep 28, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 14, so the watching starts about Aug 29 — about 127 days after the spring freeze cleared.
How long is the growing season in Kobuk?
Measured between 28°F hard freezes, Kobuk sees about 127 frost-free days — roughly May 24 through Sep 28, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 14 to Sep 14, about 92 days.
Is the soil safe to grow vegetables in Kobuk?
The federal record around Kobuk is light — 9 documented sites across the 9 federal source types we checked, mostly Mining entries (7), the nearest Nitrate record about 1.0 miles out — and proximity to a documented site is information, not a diagnosis of any one yard. Growing food here starts from a strong position; a soil test before new food beds settles any site-specific question.
How do gardeners stretch the season in Kobuk?
With about 127 frost-free days between hard freezes, Kobuk 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 155 to 183 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 24 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Kobuk's scale — its 1b band and its 127-day season. Your yard writes its own version of Kobuk'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 Kobuk’s own scale
3 of the readings below were taken at Kobuk's own scale — the 9,811 acres it covers and 9 documented sites around it; 6 are borrowed from a wider read, named and linked below.
Measured here
- Kobuk's own USDA hardiness band, zones 1bUSDA PHZM 2023
- 9 documented contamination sites on the federal record near Kobuk, the closest Nitrate record about 1.0 miles out from the town centreFederal environmental registers
- Kobuk's boundary and the 9,811 acres inside itUS Census TIGER/Line 2025
Inherited from a wider read
- The 28°F hard-freeze dates — Kobuk has no normal of its own, so its county's is the closest measured readfrom Northwest Arctic Borough
- Soil character — no town-scale survey exists, so Kobuk's 9,811 acres read through its county's SSURGO summaryfrom Northwest Arctic County
- The candidate plant list — Alaska's curated set, filtered to this zone band and re-ordered by how much margin each has herefrom Alaska
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Northwest Arctic County
- The growing challenges every Alaska grower plans around — written at state scale, so they stay on the state guidefrom Alaska
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Northwest Arctic County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Kobuk's 9,811 acreswhy one lot differs from the next →
- Which side of Kobuk you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 9,811 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 1.0 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 Kobuk-wide figureread your own land →
More in Alaska
Wider growing context
What grows across AlaskaKobuk sits outside our named growing regions, so Alaska as a whole is its closest context here.