The Interior Alaska / Tanana Valley (Fairbanks) spans USDA hardiness zones 1b-4a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Interior Alaska grows on a knife-edge no other American garden shares: a continental cold pocket where winters bottom out near -40F and the region spans zone 1b-4a, its inhabited Tanana floor running roughly 1b-2b — among the coldest settled hardiness zones in the country — yet Fairbanks summers deliver up to ~21 hours of daylight. That midnight sun is the trade: cold-hardy, quick-maturing varieties sprint through an ~85-118 day frost-free window (as short as 85 days out toward Delta Junction and Tok). Success here is a distinct discipline built on high tunnels, short-season cultivars, and exploiting long light — nothing about it resembles the maritime panhandle or the milder Mat-Su, and the coarse state page (a flat 3a-4b) cannot express a 1b-4a region whose settled floor sits at the cold end of that band on a ~90-day season. Among the crops suited to this profile: cabbage, potato, rhubarb, and kale. The site-level story — soil, sun, drainage — decides the rest.
The Interior Alaska / Tanana Valley (Fairbanks) spans Alaska.
Your yard isn't all of the Interior Alaska / Tanana Valley (Fairbanks).
The Interior Alaska / Tanana Valley (Fairbanks) spans USDA zones 1b-4a, but your parcel sits in exactly one — and slope, tree cover, and low spots nudge it further. 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 Interior Alaska / Tanana Valley (Fairbanks) — soil, climate, flood, and parcel records. How we handle your address.
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The Interior Alaska / Tanana Valley (Fairbanks) — the short answer
The Interior Alaska / Tanana Valley (Fairbanks): USDA zones 1b-4a, 85–118 frost-free days depending where in it you stand, in Alaska.
- USDA zones
- 1b-4a
- USDA PHZM 2023, aggregated over the footprint
- Shortest season here
- 85 days
- NOAA Regional Climate Centers ACIS, 1991-2020 — Southeast Fairbanks County
- Counties
- 4
- US Census TIGER/Line 2025
- Region type
- County cluster
- Growable Ground growing-region registry
Region boundary: Growable Ground growing-region registry — curated county clusters, EPA Level III ecoregions, and town clusters drawn finer than any county. The season figure is this region's own record, measured across its 4 member counties, not a state or national average.
Hardiness Zone Range
The Interior Alaska / Tanana Valley (Fairbanks) is not one growing season
One answer for the Interior Alaska / Tanana Valley (Fairbanks) averages 4 counties whose growing seasons are 33 days apart — from 85 frost-free days in Southeast Fairbanks County to 118 in Yukon-Koyukuk County. That is the same region, measured the same way, in the same years. Which end of it your land sits nearer decides what finishes before the first hard freeze.
The middle half of 4 counties runs 107–118 days, with a median of 116 days — a 33-day span end to end.
Measured across 4 member counties, each carrying its own 28°F normal. NOAA Regional Climate Centers ACIS, 1991-2020. A member with no own record is absent from the range rather than counted as zero — nothing here is interpolated to the region. Your own site sits somewhere inside this range; a parcel report resolves where.
What Grows in the Interior Alaska / Tanana Valley (Fairbanks)
All 1 of the plants below that publish a season requirement clear even Southeast Fairbanks County’s 85 frost-free days — so on season alone, this grid works at both ends of the region. The 33-day spread still decides how far past this list you can push, and how early you can start.
Plants matched to the Interior Alaska / Tanana Valley (Fairbanks)'s USDA zones 1b-4a, ordered by how much hardiness margin each has across the region — the ones with room to spare at both ends of this band lead. Each links to its full growing profile.
Native Plants of the Interior Alaska / Tanana Valley (Fairbanks)
Plants the USDA PLANTS Database documents as native and present in this region’s state, kept only where the published hardiness range meets the Interior Alaska / Tanana Valley (Fairbanks)’s USDA zones 1b-4a — closest range match first. Presence is recorded by state, so a plant can be documented across the state and still be scarce in your corner of the region.
The ground across the Interior Alaska / Tanana Valley (Fairbanks)
The USDA soil survey maps this ground county by county. These are those records weighted by land area across four member counties — this region’s own profile, not a state figure.
The ground is predominantly Gelisols, at 48% of mapped acres, followed by Inceptisols (30%), Spodosols (9%) and Entisols (8%). Seven soil orders appear somewhere inside the footprint, which is the honest reason a regional soil answer only goes so far. The most extensive named soils are Seventeenmile, Tajittro, and Tlozhavun.
39% of those acres are well drained, and another 38% poorly drained, 10% very poorly drained. Topsoil pH runs 4.8–6.5 between the lowest and the highest county on record.
Soil order
Gelisols
Drainage
Well drained
Topsoil pH
4.8–6.5
Hydric soils
49%
Soil changes across a driveway, so which of these your own ground sits on is a parcel question rather than a regional one. Yukon-Koyukuk County holds the most wetland ground here, at 51% — soil types explained.
USDA NRCS SSURGO via Soil Data Access
What this means for growing in the Interior Alaska / Tanana Valley (Fairbanks)
The soil survey reads this ground county by county, and the readings above are those records summed across the Interior Alaska / Tanana Valley (Fairbanks). Here is what they mean for a garden here — and the move an experienced grower makes about each one.
Drainage
From county records39% of the mapped acres across the Interior Alaska / Tanana Valley (Fairbanks) are well drained — ground that drains quickly. That is area-weighted across all four of its mapped counties.
The upside is soil you can work early in spring and roots that never drown; the cost is that fast-draining ground dries out fast and leaches nutrients away before plants can use them.
Work in compost and mulch to hold moisture and feed, and water more often in short doses than deep and rarely.
USDA NRCS SSURGO
Surface pH
From county recordsTopsoil across the Interior Alaska / Tanana Valley (Fairbanks) runs pH 4.8–6.5 — acidic in all four of them.
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
Wet ground
From county recordsAbout 49% of the ground across the Interior Alaska / Tanana Valley (Fairbanks) is mapped as hydric — wetland — soil. Yukon-Koyukuk County carries the most, at 51%.
If your lot falls in one of those pockets, a standard in-ground bed will fight waterlogging all season, and roots that need air will struggle.
Check how your own ground drains before you dig; raised beds or moisture-loving plantings turn a wet corner from a problem into a niche.
USDA NRCS SSURGO
Safe to Grow Here?
What the federal record shows across the Interior Alaska / Tanana Valley (Fairbanks) — and how to grow with it.
Across the Interior Alaska / Tanana Valley (Fairbanks)'s 4 counties the federal record holds 3,202 documented sites, mostly Mining (1,535), Nitrate (734) and Underground Storage Tanks (585). The heaviest single county is Fairbanks North Star County, with 1,523.
That is a regional count, not a reading of any one lot — proximity to a documented site is information, not a diagnosis. Open the map outlined to the Interior Alaska / Tanana Valley (Fairbanks) to see which records sit where you actually grow.
Sources Checked
Summed across the 4 counties in the Interior Alaska / Tanana Valley (Fairbanks)
A note from Gnorman
What an experienced grower watches for around here
In and around the Interior Alaska / Tanana Valley (Fairbanks), two things run higher than the national average across the 4 counties in the Interior Alaska / Tanana Valley (Fairbanks) — Mining (1,535 sites) and Superfund (60 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).
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
Your land is one point inside the Interior Alaska / Tanana Valley (Fairbanks)
Everything above resolves to the Interior Alaska / Tanana Valley (Fairbanks) as a whole — a footprint whose own counties record seasons 33 days apart, and hardiness across zones 1b-4a. Your parcel sits at one point in that range, not in the middle of it. 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 region 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 regional average.
Your Lot vs the Interior Alaska / Tanana Valley (Fairbanks) Average
Interior Alaska / Tanana Valley (Fairbanks) Average
- ●USDA Zones 1b-4a, averaged across Interior Alaska / Tanana Valley (Fairbanks)
- ●One soil character for all of Interior Alaska / Tanana Valley (Fairbanks)
- ●State-average frost dates
YOUR Parcel
- ✓Your exact zone, not Interior Alaska / Tanana Valley (Fairbanks)'s 1b-4a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in the Interior Alaska / Tanana Valley (Fairbanks)
Pull a site-specific report for your exact address in the Interior Alaska / Tanana Valley (Fairbanks) — soil, sun, drainage, frost risk, contamination, and scored plant recommendations.
Three things about your lot that Interior Alaska / Tanana Valley (Fairbanks) averages can't show:
We read public map data around The Interior Alaska / Tanana Valley (Fairbanks) — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Interior Alaska / Tanana Valley (Fairbanks) average
How we know this about the Interior Alaska / Tanana Valley (Fairbanks)
The boundary: a cluster of neighboring counties. Growing regions have no official boundary, so this footprint is our published one, and every figure on this page was measured over the counties inside it rather than borrowed from the state around it.
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, aggregated across the footprint; the growing season from NOAA Regional Climate Centers ACIS 1991–2020 28°F normals, read at each member’s own record; boundaries from US Census TIGER/Line 2025; the contamination record from the federal sources named in that beat above; the soil from the USDA NRCS SSURGO survey, read at each member county’s own record and weighted to this footprint by land area. Where a member carries no record of its own, it is absent from the figure rather than filled in.
Common questions about the Interior Alaska / Tanana Valley (Fairbanks)
What hardiness zone is the Interior Alaska / Tanana Valley (Fairbanks)?
The Interior Alaska / Tanana Valley (Fairbanks) spans USDA hardiness zones 1b-4a, aggregated from the USDA Agricultural Research Service Plant Hardiness Zone Map 2023 across the region's counties. Zones reflect average annual extreme minimum temperatures from 1991–2020 data.
How long is the growing season in the Interior Alaska / Tanana Valley (Fairbanks)?
Measured between 28°F hard freezes, the Interior Alaska / Tanana Valley (Fairbanks)'s counties mostly run 107 to 118 frost-free days, median 116 (NOAA Regional Climate Centers ACIS, 1991–2020, over 4 member counties). That 11-day spread is the honest read — no single season describes 4 counties, and each county guide below carries its own.
When does frost risk end in the Interior Alaska / Tanana Valley (Fairbanks)?
Across the Interior Alaska / Tanana Valley (Fairbanks), the middle half of member counties see their last 28°F hard freeze between May 16 and May 26 (median May 20), and their first fall freeze between Sep 4 and Sep 12. Those are hard freezes, not the last light frost: tender transplants wait for about Jun 10, and elevation decides which end of a 10-day spread you garden in.
What grows well in the Interior Alaska / Tanana Valley (Fairbanks)?
The Interior Alaska / Tanana Valley (Fairbanks)'s conditions suit plants such as Cabbage, Potato, Rhubarb, Kale. What actually thrives on any one site still turns on its specific soil, sun, and drainage — we score each plant against the real conditions at your address.
How is the Interior Alaska / Tanana Valley (Fairbanks) defined?
The Interior Alaska / Tanana Valley (Fairbanks) is defined here as a curated cluster of 4 neighboring counties that share a growing character. Growing regions have no official boundary, so this footprint is our published one — every county in it is named on this page.
Which states does the Interior Alaska / Tanana Valley (Fairbanks) cover?
The Interior Alaska / Tanana Valley (Fairbanks) spans Alaska. Each state's full growing guide is linked on this page.
What other growing regions cover the same states?
Southeast Alaska / Inside Passage Panhandle, Kenai Peninsula Coast, and Matanuska–Susitna Valley (Mat-Su) share at least one state with the Interior Alaska / Tanana Valley (Fairbanks). Growing regions overlap and interlock — a single address can sit inside more than one, which is why the precise read is always the parcel, not the region.
What this page reads at the Interior Alaska / Tanana Valley (Fairbanks)’s own scale
6 of the readings below were taken at the Interior Alaska / Tanana Valley (Fairbanks)'s own scale — the zone 1b-4a band across its footprint, a median 116-day season across its 4 counties and 3,202 documented federal contamination records across its 4 counties, 1,523 of them in Fairbanks North Star County alone; one is borrowed from a wider read, named and linked below.
Measured here
- The USDA hardiness band 1b-4a aggregated across all 4 counties in the footprintUSDA PHZM 2023
- The boundary itself — the 4 counties this region is curated fromGrowable Ground subregion registry
- The growing character that makes this region distinct from the states it crossesGrowable Ground subregion registry
- The 28°F season across the footprint — the middle half of its 4 counties run 107 to 118 frost-free days, median 116NOAA Regional Climate Centers ACIS, 1991-2020
- The federal contamination record over the whole footprint — 3,202 documented federal contamination records across its 4 counties, 1,523 of them in Fairbanks North Star County aloneEPA, USGS and USDA federal site records
- The soil order mix across the footprint — 48% Gelisols, topsoil pH 4.8–6.5, area-weighted across its 4 mapped countiesUSDA NRCS SSURGO
Inherited from a wider read
- The candidate plant list — its state's curated sets, merged and filtered to zones 1b-4afrom Alaska
What this page can’t tell you
- Which end of the 11-day range your ground sits at — 107 days at one extreme, 118 at the other, decided mostly by elevationfrost dates explained →
- Which of those soils your own ground sits on — the survey maps them county-wide, and they change across a drivewaysoil types explained →
- The soil pH, drainage, sun hours, and frost pockets on one specific lotwhy one lot differs from the next →
Explore the Interior Alaska / Tanana Valley (Fairbanks)
State growing guides
Counties in this region
Other growing regions across Alaska
Alaska's temperate rainforest inverts the usual Alaska problem: the constraint here isn't cold, it's a lack of summer heat. The Inside Passage panhandle spans USDA zones 5a–8a overall — 7a–8a in the coastal towns where nearly all of its gardening happens (Sitka 8a, Ketchikan 7b) with a 159–240 day frost-free season — longer than much of the mountain West — yet cloudy, cool, extremely wet maritime summers on acidic, boggy Tongass soils mean heat-lovers like tomatoes and corn stall out while cool-season greens, brassicas, potatoes, rhubarb, and berries thrive. This is the mirror image of Alaska's cold-but-sunny Interior and cannot share a page with it.
Cook Inlet's maritime edge — from Homer's 6b banana-belt bluffs to Seward's 7a harbor, ocean-moderated pockets that garden far milder than the peninsula's interior river flats, on committed place records spanning 4b-7a.
Alaska's farm heartland — the Mat-Su's long June days grow the state fair's giant cabbages on a 4a-5b valley floor whose committed band runs two zones warmer than the borough's glacier-to-Denali average.