Cantwell, Alaska, sits in USDA hardiness zone 4a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
Crops well matched to these conditions include okra, cranberry, cilantro, and zucchini — though what thrives on any one site still turns on its specific soil, sun, and drainage.
Even in Cantwell, 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 Cantwell 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 Cantwell — soil, climate, flood, and parcel records. How we handle your address.
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Cantwell — the short answer
Cantwell, Alaska: USDA zone 4a, about 118 days between hard freezes, across 76K acres of town.
- USDA zone
- 4a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 24
- Denali Borough normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Sep 19
- Denali Borough normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~118
- Denali Borough normal — NOAA 1991–2020, nearest to this town
- Town area
- 76K 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 Denali Borough’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 4a is Cantwell's average, not your lot's — a low corner or a tree line moves it. Against Cantwell's 118-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Cantwell
Each reading below is measured for Cantwell itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsCantwell runs about 118 days between hard freezes (read from Denali Borough, the closest normal to Cantwell) — 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
MeasuredCantwell sits in USDA hardiness zone 4a.
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 Cantwell
Every plant below cleared Cantwell's own zone 4a and its 118-day season. Each card opens that plant's Alaska profile. How we score.
Is it too late to plant in Cantwell?
Almost never — the real question is what to plant next. 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 19 — 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 Cantwell
Closest first, within ~10 miles of Cantwell. Listing isn't leaking, and distance isn't exposure.
- Unnamed (northwest flank of Reindeer Hills)Mining · 3.6 mi
- Unnamed (west end of Reindeer Hills)Mining · 3.8 mi
- ALASKA DOT & PF CANTWELL MAINTENANCE STATIONBrownfields · 4.5 mi
- DENALI MINE CANTWELLBrownfields · 4.6 mi
- Alaska Railroad Corp ( Arrc) Cantwell SectionUnderground Storage Tanks · 4.8 mi
- ADOTPF - East Fork Maintenance StationUnderground Storage Tanks · 4.8 mi
- Gold Creek Assoc. No. 1Underground Storage Tanks · 4.8 mi
- Reindeer Mt. LodgeUnderground Storage Tanks · 4.8 mi
- Schist Creek LodeMining · 5.7 mi
- Unnamed (north of upper Schist Creek)Mining · 5.8 mi
- Unnamed (east of lower Slime Creek)Mining · 6.7 mi
Measured from Cantwell'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 Cantwell.
Total Sites
11
within ~10 miles of Cantwell
Risk Level
Low
Highest-severity
5 mining sites (prospects, none worked)
Severity Distribution
within ~10 miles of Cantwell
Highest-Severity Sites
Know Before You Grow
- •Mine waste leaches heavy metals. Test for lead, arsenic and cadmium before growing food here.
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •Near a brownfield, raised beds of imported soil give your food clean ground.
Check your specific parcel in Cantwell
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 Cantwell average
Your land is one point inside Cantwell
Everything above resolves to Cantwell as a whole — one PHZM band, read across 76K acres, with hard-freeze dates borrowed from Denali Borough’s record because no 30-year normal resolves at this town’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 town 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 Cantwell Average
Cantwell Average
- ●USDA Zones 4a, averaged across Cantwell
- ●One soil character for all of Cantwell
- ●Frost dates read at Cantwell's scale: May 24 to Sep 19
YOUR Parcel
- ✓Your exact zone, not Cantwell's 4a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Cantwell
Pull a site-specific report for your exact address in Cantwell, Alaska — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Cantwell averages can't show:
We read public map data around Cantwell — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Cantwell average
How we know this about Cantwell
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this town’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Denali 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 town grain anywhere on this page — there is no town-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 Cantwell
When does frost risk typically end in Cantwell?
The last hard freeze (28°F) in Cantwell 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 Cantwell?
The first hard freeze (28°F) in Cantwell typically arrives around Sep 19, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 5, so the watching starts about Aug 20 — about 118 days after the spring freeze cleared.
How long is the growing season in Cantwell?
Measured between 28°F hard freezes, Cantwell sees about 118 frost-free days — roughly May 24 through Sep 19, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 14 to Sep 5, about 83 days.
Is the soil safe to grow vegetables in Cantwell?
The federal record around Cantwell is light — 11 documented sites across the 9 federal source types we checked, mostly Mining entries (5), the nearest Mining record about 3.6 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 Cantwell?
With about 118 frost-free days between hard freezes, Cantwell 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 24 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Cantwell's scale — its 4a band and its 118-day season. Your yard writes its own version of Cantwell'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 Cantwell’s own scale
4 of the readings below were taken at Cantwell's own scale — the 76,172 acres it covers and 11 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Cantwell's own USDA hardiness band, zones 4aUSDA PHZM 2023
- 11 documented contamination sites on the federal record near Cantwell, the closest Mining record about 3.6 miles out from the town centreFederal environmental registers
- Cantwell's boundary and the 76,172 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4a and a ~118-day seasonGrowable Ground crop-matching engine
Inherited from a wider read
- The 28°F hard-freeze dates — Cantwell has no normal of its own, so its county's is the closest measured readfrom Denali Borough
- Soil character — no town-scale survey exists, so Cantwell's 76,172 acres read through its county's SSURGO summaryfrom Denali County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Denali 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 Denali County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Cantwell's 76,172 acreswhy one lot differs from the next →
- Which side of Cantwell you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 76,172 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Mining record about 3.6 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 Cantwell-wide figureread your own land →
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