Yukon-Koyukuk Census Area, in Alaska, sits in USDA hardiness zones 3a-4b — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
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.
Yukon-Koyukuk Census Area lies within the Interior Alaska / Tanana Valley (Fairbanks) — a regional growing area with its own character.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Yukon-Koyukuk Census Area holds more than one microclimate.
Soils and elevations shift across Yukon-Koyukuk Census Area, 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 Yukon-Koyukuk Census Area — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Yukon-Koyukuk Census Area — the short answer
Yukon-Koyukuk Census Area, Alaska: USDA zones 3a-4b, about 118 days between hard freezes, across 93.3M acres.
- USDA zones
- 3a-4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 15
- TANANA AIRPORT station, 225 ft — 33 km away, 30 yr record
- First hard freeze (28°F)
- Sep 10
- TANANA AIRPORT station, 225 ft — 33 km away, 30 yr record
- Days between freezes
- ~118
- TANANA AIRPORT station, 225 ft — 33 km away, 30 yr record
- County area
- 93.3M 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 Yukon-Koyukuk Census Area's average, not your lot's — a low corner or a tree line moves it. Against Yukon-Koyukuk Census Area's 118-day season, see what your own ground reads.
Soil in Yukon-Koyukuk County
Across Yukon-Koyukuk County, the ground is predominantly Gelisols, where Seventeenmile, Tajittro, and Tlozhavun are the most extensive named soil series. The soil is generally well drained with a silt loam surface. Topsoil pH runs about 5.0–6.5, moderately acidic. Rainfall drains through hydrologic group D soils.
Soil order
Gelisols
Drainage
Well drained
Hydric soils
51%
Soil still varies lot by lot — soil types explained.
How the ground varies across Yukon-Koyukuk Census Area
The USDA soil survey maps 44% of Yukon-Koyukuk Census Area as well drained — but another 54% drains differently: 37% poorly drained, 10% very poorly drained.
Seventeenmile is the most extensive named soil at 4% of mapped acres, then Tajittro (2%) and Tlozhavun (1%).
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 Yukon-Koyukuk Census Area
Each reading below is measured for Yukon-Koyukuk Census Area itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Drainage
MeasuredThe dominant soils across Yukon-Koyukuk Census Area are well drained, in hydrologic group D — ground that drains quickly.
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
MeasuredTopsoil across Yukon-Koyukuk Census Area runs about pH 5.0–6.5, 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
Wet ground
MeasuredAbout 51% of Yukon-Koyukuk Census Area is mapped as hydric — wetland — soil.
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
Season length
MeasuredYukon-Koyukuk Census Area runs about 118 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
What Grows in Yukon-Koyukuk Census Area
We scored all 1,086 plants against Yukon-Koyukuk Census Area's own USDA zone 3a-4b and its own 118-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 Yukon-Koyukuk Census Area?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Apr 17; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 15 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 10 — 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 Yukon-Koyukuk County — and how to grow with it.
We checked the federal record across Yukon-Koyukuk County — 926 documented sites across 7 of the 9 source types we track.
The most significant on record: 20 Superfund sites (none NPL-listed). Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
Yukon-Koyukuk Census Area 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 Yukon-Koyukuk Census Area
Closest first, across Yukon-Koyukuk County. Listing isn't leaking, and distance isn't exposure.
- Quartz Creek ProspectMining · 9.1 mi
- Bonanza KingMining · 9.3 mi
- Quartz Creek LodeMining · 9.8 mi
- American Creek PlacerMining · 11.6 mi
- USAF LRRS BEAR CREEKBrownfields · 12.9 mi
- USAF LRRS BEAR CREEKSuperfund · 12.9 mi
- Boulder CreekMining · 19.1 mi
- Tanana Zone HeadquarterUnderground Storage Tanks · 20.2 mi
- Tanana Health CenterUnderground Storage Tanks · 20.2 mi
- FAA TananaUnderground Storage Tanks · 20.2 mi
- Tanana CommercialUnderground Storage Tanks · 20.2 mi
- Tanana Gas CompanyUnderground Storage Tanks · 20.2 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Yukon-Koyukuk Census Area'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 Yukon-Koyukuk Census Area.
Total Sites
926
across Yukon-Koyukuk County
Risk Level
High
Highest-severity
20 Superfund sites (none NPL-listed)
Sources Checked
across Yukon-Koyukuk County
Severity Distribution
across Yukon-Koyukuk County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Yukon-Koyukuk Census Area, two things run higher than the national average across Yukon-Koyukuk County — Mining (732 sites) and Superfund (20 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 Yukon-Koyukuk Census Area
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 Yukon-Koyukuk Census Area average
Your land is one point inside Yukon-Koyukuk Census Area
Everything above resolves to Yukon-Koyukuk Census Area as a whole — one PHZM band and one county frost record, read across 93.3M 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 Yukon-Koyukuk Census Area Average
Yukon-Koyukuk Census Area Average
- ●USDA Zones 3a-4b, averaged across Yukon-Koyukuk Census Area
- ●One soil character for all of Yukon-Koyukuk Census Area
- ●Frost dates read at Yukon-Koyukuk Census Area's scale: May 15 to Sep 10
YOUR Parcel
- ✓Your exact zone, not Yukon-Koyukuk Census Area's 3a-4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Yukon-Koyukuk Census Area
Pull a site-specific report for your exact address in Yukon-Koyukuk Census Area, Alaska — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Yukon-Koyukuk Census Area averages can't show:
We read public map data around Yukon-Koyukuk Census Area — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Yukon-Koyukuk Census Area average
How we know this about Yukon-Koyukuk Census Area
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 Yukon-Koyukuk Census Area carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Yukon-Koyukuk Census Area
When does frost risk typically end in Yukon-Koyukuk Census Area?
The last hard freeze (28°F) in Yukon-Koyukuk Census Area typically lands around May 15, 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 5.
How long is the growing season in Yukon-Koyukuk Census Area?
Measured between 28°F hard freezes, Yukon-Koyukuk Census Area sees about 118 frost-free days — roughly May 15 through Sep 10, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 5 to Aug 27, about 83 days.
Is the soil safe to grow vegetables in Yukon-Koyukuk Census Area?
The federal record around Yukon-Koyukuk Census Area runs heavier than most — 926 documented sites, mostly Mining entries (732), the nearest Mining record about 9.1 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 Yukon-Koyukuk Census Area?
With about 118 frost-free days between hard freezes, Yukon-Koyukuk Census Area 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 146 to 174 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 15 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Yukon-Koyukuk Census Area's scale — its 3a-4b band and its 118-day season. Your yard writes its own version of Yukon-Koyukuk Census Area'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 Yukon-Koyukuk Census Area’s own scale
6 of the readings below were taken at Yukon-Koyukuk Census Area's own scale — its own ~118-day span between 28°F freezes, the 3 most extensive soil series mapped here and 926 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Yukon-Koyukuk Census Area's own USDA hardiness band, zones 3a-4bUSDA PHZM 2023
- Yukon-Koyukuk Census Area's own 28°F hard-freeze dates and its ~118-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Yukon-Koyukuk Census AreaUSDA NRCS SSURGO
- 926 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Mining record about 9.1 miles outFederal environmental registers
- Yukon-Koyukuk Census Area's boundary and the 93,291,106 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 3a-4b and a ~118-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 Yukon-Koyukuk Census Area — the ~118 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 Yukon-Koyukuk Census Area's 93,291,106 acreswhy one lot differs from the next →
- Which of those 926 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 Yukon-Koyukuk Census Arearead your own land →