Northwest Arctic Borough, in Alaska, sits in USDA hardiness zones 3a-4b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Crops well matched to these conditions include cabbage, cranberry, epazote, and collard greens — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Northwest Arctic Borough holds more than one microclimate.
Soils and elevations shift across Northwest Arctic Borough, 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 Northwest Arctic Borough — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Northwest Arctic Borough — the short answer
Northwest Arctic Borough, Alaska: USDA zones 3a-4b, about 127 days between hard freezes, across 22.8M acres.
- USDA zones
- 3a-4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 24
- KOTZEBUE AIRPORT station, 11 ft — 113 km away, 29 yr record
- First hard freeze (28°F)
- Sep 28
- KOTZEBUE AIRPORT station, 11 ft — 113 km away, 29 yr record
- Days between freezes
- ~127
- KOTZEBUE AIRPORT station, 11 ft — 113 km away, 29 yr record
- County area
- 22.8M 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 3a-4b is Northwest Arctic Borough's average, not your lot's — a low corner or a tree line moves it. Against Northwest Arctic Borough's 127-day season, see what your own ground reads.
Soil in Northwest Arctic County
Across Northwest Arctic County, the ground is predominantly Gelisols, where Uvluutit, Urgiilik, and Kikku are the most extensive named soil series. The soil is generally very poorly drained with a mucky silt loam surface. Topsoil pH runs about 4.8–5.1, very strongly acidic. Rainfall drains through hydrologic group D soils.
Soil order
Gelisols
Drainage
Very poorly drained
Hydric soils
61%
Soil still varies lot by lot — soil types explained.
How the ground varies across Northwest Arctic Borough
The USDA soil survey maps 33% of Northwest Arctic Borough as very poorly drained — but another 47% drains differently: 27% poorly drained, 16% well drained.
Uvluutit is the most extensive named soil at 0% of mapped acres, then Urgiilik (0%) and Kikku (0%).
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 Northwest Arctic Borough
Each reading below is measured for Northwest Arctic Borough itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Drainage
MeasuredThe dominant soils across Northwest Arctic Borough are very poorly drained, in hydrologic group D — ground that sheds water slowly.
Beds can stay saturated for days after heavy rain, and the roots of most vegetables, berries, and fruit trees suffocate or rot in soil that never drains.
Raised beds or mounded rows lift roots above the wet zone; choose water-tolerant crops for the lowest spots.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Northwest Arctic Borough runs about pH 4.8–5.1, on the acidic side.
Blueberries, potatoes, and rhododendrons thrive in it, but most vegetables start locking out nutrients below about pH 6.0 and grow pale and stunted no matter how much you feed them.
A measured lime application raises pH for the crops that need it — but test first, because the right rate depends on your own soil, not the county average.
USDA NRCS SSURGO
Season length
MeasuredNorthwest Arctic Borough runs about 127 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
MeasuredNorthwest Arctic Borough sits in USDA hardiness zones 3a-4b.
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 Northwest Arctic Borough
We scored all 1,086 plants against Northwest Arctic Borough's own USDA zone 3a-4b and its own 127-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 Alaska profile.
Is it too late to plant in Northwest Arctic Borough?
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.
Safe to Grow Here?
What the federal record shows across Northwest Arctic County — and how to grow with it.
We checked the federal record across Northwest Arctic County — 279 documented sites across 6 of the 9 source types we track.
The most significant on record: 7 Superfund sites (none NPL-listed). Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Northwest Arctic Borough carries one of the heavier federal records we track — and that's not a verdict on your yard. Proximity to a documented site is information, not a diagnosis: nothing here says any particular parcel is affected. It does earn one concrete step — before food beds go in the ground, a professional soil test tells you exactly what you're working with, and raised beds with clean imported soil grow well almost anywhere in the meantime.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Northwest Arctic Borough
Closest first, across Northwest Arctic County. Listing isn't leaking, and distance isn't exposure.
- FrostMining · 37.1 mi
- Unnamed OccurenceMining · 37.5 mi
- PowdermilkMining · 37.6 mi
- UnnamedMining · 39.0 mi
- OmarMining · 40.5 mi
- TembyMining · 40.8 mi
- Nakolikurok CreekMining · 44.1 mi
- MalfiattiMining · 45.5 mi
- Akiak Cr- MalfiattiMining · 45.6 mi
- Salmon RiverMining · 46.6 mi
- UhlMining · 48.5 mi
- GallahornMining · 52.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Northwest Arctic Borough'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 Northwest Arctic Borough.
Total Sites
279
across Northwest Arctic County
Risk Level
High
Highest-severity
7 Superfund sites (none NPL-listed)
Sources Checked
across Northwest Arctic County
Severity Distribution
across Northwest Arctic County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Northwest Arctic Borough, two things run higher than the national average across Northwest Arctic County — Mining (239 sites) and Superfund (7 sites). Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in Northwest Arctic Borough
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 Northwest Arctic Borough average
Your land is one point inside Northwest Arctic Borough
Everything above resolves to Northwest Arctic Borough as a whole — one PHZM band and one county frost record, read across 22.8M 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 Northwest Arctic Borough Average
Northwest Arctic Borough Average
- ●USDA Zones 3a-4b, averaged across Northwest Arctic Borough
- ●One soil character for all of Northwest Arctic Borough
- ●Frost dates read at Northwest Arctic Borough's scale: May 24 to Sep 28
YOUR Parcel
- ✓Your exact zone, not Northwest Arctic Borough's 3a-4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Northwest Arctic Borough
Pull a site-specific report for your exact address in Northwest Arctic Borough, Alaska — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Northwest Arctic Borough averages can't show:
We read public map data around Northwest Arctic Borough — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Northwest Arctic Borough average
How we know this about Northwest Arctic Borough
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 Northwest Arctic Borough carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Northwest Arctic Borough
When does frost risk typically end in Northwest Arctic Borough?
The last hard freeze (28°F) in Northwest Arctic Borough 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.
How long is the growing season in Northwest Arctic Borough?
Measured between 28°F hard freezes, Northwest Arctic Borough 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 Northwest Arctic Borough?
The federal record around Northwest Arctic Borough runs heavier than most — 279 documented sites, mostly Mining entries (239), the nearest Mining record about 37 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 gardeners stretch the season in Northwest Arctic Borough?
With about 127 frost-free days between hard freezes, Northwest Arctic Borough 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 Northwest Arctic Borough's scale — its 3a-4b band and its 127-day season. Your yard writes its own version of Northwest Arctic Borough'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 Alaska's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Northwest Arctic Borough’s own scale
6 of the readings below were taken at Northwest Arctic Borough's own scale — its own ~127-day span between 28°F freezes, the 3 most extensive soil series mapped here and 279 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Northwest Arctic Borough's own USDA hardiness band, zones 3a-4bUSDA PHZM 2023
- Northwest Arctic Borough's own 28°F hard-freeze dates and its ~127-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Northwest Arctic BoroughUSDA NRCS SSURGO
- 279 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Mining record about 37 miles outFederal environmental registers
- Northwest Arctic Borough's boundary and the 22,829,865 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 3a-4b and a ~127-day seasonGrowable Ground crop-matching engine
Inherited from a wider read
- The growing challenges every Alaska grower plans around — written at state scale, so they stay on the state guidefrom Alaska
What this page can’t tell you
- How the season shifts across Northwest Arctic Borough — the ~127 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 Northwest Arctic Borough's 22,829,865 acreswhy one lot differs from the next →
- Which of those 279 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 Northwest Arctic Boroughread your own land →