Glennallen, Alaska, sits in USDA hardiness zone 3a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Reliable performers under these conditions include cabbage, potato, rhubarb, and kale; what your own ground favors still comes down to its soil, sun, and drainage.
Even in Glennallen, 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 Glennallen 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 Glennallen — soil, climate, flood, and parcel records. How we handle your address.
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Glennallen — the short answer
Glennallen, Alaska: USDA zone 3a, about 109 days between hard freezes, across 74K acres of town.
- USDA zone
- 3a
- 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
- 74K 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 3a is Glennallen's average, not your lot's — a low corner or a tree line moves it. Against Glennallen's 109-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Glennallen
Each reading below is measured for Glennallen itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsGlennallen runs about 109 days between hard freezes (read from Copper River Census Area, the closest normal to Glennallen) — 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
MeasuredGlennallen sits in USDA hardiness zone 3a.
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 Glennallen
Plants matched to Glennallen's USDA zones 3a, ordered by how much hardiness margin each has here — the ones with room to spare at both ends of this town's band lead. Each links to its full growing profile.
Is it too late to plant in Glennallen?
Almost never — the real question is what to plant next. 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 Glennallen
Closest first, within ~10 miles of Glennallen. Listing isn't leaking, and distance isn't exposure.
- CB00400230BBAA1 002Nitrate · 6.4 mi
- CB00400230BABA2 001Nitrate · 6.5 mi
- CB00400223CCBA1 011Nitrate · 9.6 mi
- CB00400223CBDC1 006Nitrate · 9.7 mi
- WRANGELL ST ELIAS NP GLENN HWYBrownfields · 9.9 mi
- CB00400223CDBB1 008Nitrate · 9.9 mi
- CB00400223CDAB1 003Nitrate · 10.0 mi
Measured from Glennallen'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 Glennallen.
Severity Distribution
within ~10 miles of Glennallen
Highest-Severity Sites
Know Before You Grow
- •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 Glennallen
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 Glennallen average
Your land is one point inside Glennallen
Everything above resolves to Glennallen as a whole — one PHZM band, read across 74K 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 Glennallen Average
Glennallen Average
- ●USDA Zones 3a, averaged across Glennallen
- ●One soil character for all of Glennallen
- ●Frost dates read at Glennallen's scale: May 21 to Sep 7
YOUR Parcel
- ✓Your exact zone, not Glennallen's 3a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Glennallen
Pull a site-specific report for your exact address in Glennallen, Alaska — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Glennallen averages can't show:
We read public map data around Glennallen — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Glennallen average
How we know this about Glennallen
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 Glennallen
When does frost risk typically end in Glennallen?
The last hard freeze (28°F) in Glennallen 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 Glennallen?
The first hard freeze (28°F) in Glennallen 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 Glennallen?
Measured between 28°F hard freezes, Glennallen 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 Glennallen?
The federal record around Glennallen is light — 14 documented sites across the 9 federal source types we checked, mostly Nitrate entries (12), the nearest Nitrate record about 6.4 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 Glennallen?
With about 109 frost-free days between hard freezes, Glennallen 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 Glennallen's scale — its 3a band and its 109-day season. Your yard writes its own version of Glennallen'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 Glennallen’s own scale
3 of the readings below were taken at Glennallen's own scale — the 73,576 acres it covers and 14 documented sites around it; 6 are borrowed from a wider read, named and linked below.
Measured here
- Glennallen's own USDA hardiness band, zones 3aUSDA PHZM 2023
- 14 documented contamination sites on the federal record near Glennallen, the closest Nitrate record about 6.4 miles out from the town centreFederal environmental registers
- Glennallen's boundary and the 73,576 acres inside itUS Census TIGER/Line 2025
Inherited from a wider read
- The 28°F hard-freeze dates — Glennallen 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 Glennallen's 73,576 acres read through its county's SSURGO summaryfrom Copper River County
- The candidate plant list — Alaska's curated set, filtered to this zone band and re-ordered by how much margin each has herefrom Alaska
- 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 Glennallen's 73,576 acreswhy one lot differs from the next →
- Which side of Glennallen you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 73,576 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 6.4 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 Glennallen-wide figureread your own land →
More in Alaska
Wider growing context
What grows across AlaskaGlennallen sits outside our named growing regions, so Alaska as a whole is its closest context here.
Nearby growing guides