Tonsina, Alaska, sits in USDA hardiness zone 4b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Expect zucchini, cranberry, cilantro, and okra to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Even in Tonsina, 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 Tonsina 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 Tonsina — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Tonsina — the short answer
Tonsina, Alaska: USDA zone 4b, about 109 days between hard freezes, across 102K acres of town.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 21
- Copper River Census Area normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Sep 7
- Copper River Census Area normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~109
- Copper River Census Area normal — NOAA 1991–2020, nearest to this town
- Town area
- 102K 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 Copper River Census Area’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 4b is Tonsina's average, not your lot's — a low corner or a tree line moves it. Against Tonsina's 109-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Tonsina
Each reading below is measured for Tonsina itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsTonsina runs about 109 days between hard freezes (read from Copper River Census Area, the closest normal to Tonsina) — 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
MeasuredTonsina sits in USDA hardiness zone 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 Tonsina
Every plant below cleared Tonsina's own zone 4b and its 109-day season. Each card opens that plant's Alaska profile. How we score.
Is it too late to plant in Tonsina?
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 23; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 21 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 7 — 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 Tonsina
Closest first, within ~10 miles of Tonsina. Listing isn't leaking, and distance isn't exposure.
- Bernard MountainMining · 1.4 mi
- Bernard Mountain ProspectMining · 3.5 mi
- USDOI BLM PUMP STA 12 DUMP SITESuperfund · 3.7 mi
- ALYESKA TAPS PUMP STATION 12Brownfields · 3.9 mi
- Sheep HillMining · 5.0 mi
- Sheep Mountain ProspectMining · 5.3 mi
- CD00500207DCAD1 002Nitrate · 5.9 mi
- STATE OF ALASKA DOT & PF ERNESTINE MAINTENANCE STATIONBrownfields · 6.0 mi
- Dust CreekMining · 6.3 mi
- Dust MountainMining · 7.3 mi
- Dust Mountain ProspectMining · 7.4 mi
- CORDOVA CY OF BALER SITEBrownfields · 8.0 mi
3 more sites are on the record inside the same radius. See them on the map
Measured from Tonsina'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 Tonsina.
Total Sites
19
within ~10 miles of Tonsina
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Severity Distribution
within ~10 miles of Tonsina
Highest-Severity Sites
Know Before You Grow
- •Mine waste leaches heavy metals. Test for lead, arsenic and cadmium before growing food here.
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
- •Near a brownfield, raised beds of imported soil give your food clean ground.
Check your specific parcel in Tonsina
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 Tonsina average
Your land is one point inside Tonsina
Everything above resolves to Tonsina as a whole — one PHZM band, read across 102K acres, with hard-freeze dates borrowed from Copper River Census Area’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 Tonsina Average
Tonsina Average
- ●USDA Zones 4b, averaged across Tonsina
- ●One soil character for all of Tonsina
- ●Frost dates read at Tonsina's scale: May 21 to Sep 7
YOUR Parcel
- ✓Your exact zone, not Tonsina's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Tonsina
Pull a site-specific report for your exact address in Tonsina, Alaska — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Tonsina averages can't show:
We read public map data around Tonsina — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Tonsina average
How we know this about Tonsina
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 Copper River Census Area’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 Tonsina
When does frost risk typically end in Tonsina?
The last hard freeze (28°F) in Tonsina typically lands around May 21, 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 11.
When is the first frost in Tonsina?
The first hard freeze (28°F) in Tonsina typically arrives around Sep 7, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Aug 24, so the watching starts about Aug 8 — about 109 days after the spring freeze cleared.
How long is the growing season in Tonsina?
Measured between 28°F hard freezes, Tonsina sees about 109 frost-free days — roughly May 21 through Sep 7, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 11 to Aug 24, about 74 days.
Is the soil safe to grow vegetables in Tonsina?
The federal record around Tonsina is a meaningful one — 19 documented sites, mostly Mining entries (9), the nearest Mining record about 1.4 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 Tonsina?
With about 109 frost-free days between hard freezes, Tonsina 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 137 to 165 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 21 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Tonsina's scale — its 4b band and its 109-day season. Your yard writes its own version of Tonsina'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 Tonsina’s own scale
4 of the readings below were taken at Tonsina's own scale — the 101,756 acres it covers and 19 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Tonsina's own USDA hardiness band, zones 4bUSDA PHZM 2023
- 19 documented contamination sites on the federal record near Tonsina, the closest Mining record about 1.4 miles out from the town centreFederal environmental registers
- Tonsina's boundary and the 101,756 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~109-day seasonGrowable Ground crop-matching engine
Inherited from a wider read
- The 28°F hard-freeze dates — Tonsina has no normal of its own, so its county's is the closest measured readfrom Copper River Census Area
- Soil character — no town-scale survey exists, so Tonsina's 101,756 acres read through its county's SSURGO summaryfrom Copper River County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Copper River 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 Copper River County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Tonsina's 101,756 acreswhy one lot differs from the next →
- Which side of Tonsina you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 101,756 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Mining record about 1.4 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 Tonsina-wide figureread your own land →
More in Alaska
Wider growing context
What grows across AlaskaTonsina sits outside our named growing regions, so Alaska as a whole is its closest context here.
Nearby growing guides