Dillingham Census Area, in Alaska, sits in USDA hardiness zones 3a-4b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Growers here do well with cabbage, cranberry, epazote, and collard greens — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Dillingham Census Area holds more than one microclimate.
Soils and elevations shift across Dillingham 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 Dillingham Census Area — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Dillingham Census Area — the short answer
Dillingham Census Area, Alaska: USDA zones 3a-4b, about 135 days between hard freezes, across 11.7M acres.
- USDA zones
- 3a-4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 13
- KING SALMON AIRPORT station, 66 ft — 133 km away, 30 yr record
- First hard freeze (28°F)
- Sep 25
- KING SALMON AIRPORT station, 66 ft — 133 km away, 30 yr record
- Days between freezes
- ~135
- KING SALMON AIRPORT station, 66 ft — 133 km away, 30 yr record
- County area
- 11.7M 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 Dillingham Census Area's average, not your lot's — a low corner or a tree line moves it. Against Dillingham Census Area's 135-day season, see what your own ground reads.
Soil in Dillingham County
Across Dillingham County, the ground is predominantly Inceptisols, where Okstukuk, Ahklun, and Klak are the most extensive named soil series. The soil is generally well drained with a highly organic silt loam surface. Topsoil pH runs about 4.2–5.3, very strongly acidic. Rainfall drains through hydrologic group B soils.
Soil order
Inceptisols
Drainage
Well drained
Hydric soils
23%
Soil still varies lot by lot — soil types explained.
How the ground varies across Dillingham Census Area
The USDA soil survey maps 68% of Dillingham Census Area as well drained — but another 26% drains differently: 11% very poorly drained, 9% moderately well drained.
Okstukuk is the most extensive named soil at 6% of mapped acres, then Ahklun (3%) and Klak (3%).
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 Dillingham Census Area
Each reading below is measured for Dillingham 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 Dillingham Census Area are well drained, in hydrologic group B — 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 Dillingham Census Area runs about pH 4.2–5.3, 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 23% of Dillingham 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
MeasuredDillingham Census Area runs about 135 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 Dillingham Census Area
We scored all 1,086 plants against Dillingham Census Area's own USDA zone 3a-4b and its own 135-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 Dillingham Census Area?
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 15; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 13 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 25 — long-season crops need about 90 days of runway, quick greens only 30. When the window is tight, the fall moves are quick ones — baby greens, radishes, and garlic set for next season.
Safe to Grow Here?
What the federal record shows across Dillingham County — and how to grow with it.
We checked the federal record across Dillingham County — 82 documented sites across 5 of the 9 source types we track.
The most significant on record: 4 Superfund sites (none NPL-listed). Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
There's a meaningful federal record across Dillingham County — worth a look before you plant food, not a reason to hold back from growing. Proximity to a documented site is information, not a diagnosis of any one yard. A soil test before new food beds is the sensible precaution here, and the map shows exactly which sites sit where, so you can see what's actually near you.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Dillingham Census Area
Closest first, across Dillingham County. Listing isn't leaking, and distance isn't exposure.
- Kamuk Mtn. DepositMining · 17.3 mi
- ArcanaMining · 20.2 mi
- Red TopMining · 20.4 mi
- Marsh MountainMining · 20.7 mi
- USDOI BLM RED TOP MINESuperfund · 21.3 mi
- Silver HornMining · 23.4 mi
- Lake AleknagikMining · 23.7 mi
- Wood RiverMining · 29.9 mi
- Unnamed (southwest of Sunshine Valley)Mining · 30.0 mi
- Little Togiak LakeMining · 32.6 mi
- SC00804729DBCD2 001Nitrate · 34.1 mi
- SC00804729DBCD1 001Nitrate · 34.1 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Dillingham 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 Dillingham Census Area.
Total Sites
82
across Dillingham County
Risk Level
Elevated
Highest-severity
4 Superfund sites (none NPL-listed)
Sources Checked
across Dillingham County
Severity Distribution
across Dillingham County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Dillingham Census Area, two things run higher than the national average across Dillingham County — Mining (46 sites) and Superfund (4 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around 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.
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 Dillingham 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 Dillingham Census Area average
Your land is one point inside Dillingham Census Area
Everything above resolves to Dillingham Census Area as a whole — one PHZM band and one county frost record, read across 11.7M 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 Dillingham Census Area Average
Dillingham Census Area Average
- ●USDA Zones 3a-4b, averaged across Dillingham Census Area
- ●One soil character for all of Dillingham Census Area
- ●Frost dates read at Dillingham Census Area's scale: May 13 to Sep 25
YOUR Parcel
- ✓Your exact zone, not Dillingham Census Area's 3a-4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Dillingham Census Area
Pull a site-specific report for your exact address in Dillingham Census Area, Alaska — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Dillingham Census Area averages can't show:
We read public map data around Dillingham Census Area — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Dillingham Census Area average
How we know this about Dillingham 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 Dillingham Census Area carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Dillingham Census Area
When does frost risk typically end in Dillingham Census Area?
The last hard freeze (28°F) in Dillingham Census Area typically lands around May 13, 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 3.
How long is the growing season in Dillingham Census Area?
Measured between 28°F hard freezes, Dillingham Census Area sees about 135 frost-free days — roughly May 13 through Sep 25, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 3 to Sep 11, about 100 days.
Is the soil safe to grow vegetables in Dillingham Census Area?
The federal record around Dillingham Census Area is a meaningful one — 82 documented sites, mostly Mining entries (46), the nearest Mining record about 17 miles 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 Dillingham Census Area?
With about 135 frost-free days between hard freezes, Dillingham 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 163 to 191 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 13 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Dillingham Census Area's scale — its 3a-4b band and its 135-day season. Your yard writes its own version of Dillingham 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 Dillingham Census Area’s own scale
6 of the readings below were taken at Dillingham Census Area's own scale — its own ~135-day span between 28°F freezes, the 3 most extensive soil series mapped here and 82 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Dillingham Census Area's own USDA hardiness band, zones 3a-4bUSDA PHZM 2023
- Dillingham Census Area's own 28°F hard-freeze dates and its ~135-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Dillingham Census AreaUSDA NRCS SSURGO
- 82 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Mining record about 17 miles outFederal environmental registers
- Dillingham Census Area's boundary and the 11,746,030 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 3a-4b and a ~135-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 Dillingham Census Area — the ~135 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 Dillingham Census Area's 11,746,030 acreswhy one lot differs from the next →
- Which of those 82 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 Dillingham Census Arearead your own land →