Mill Bay, Alaska, sits in USDA hardiness zone 7b — 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, fig, california poppy, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Even in Mill Bay, 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 Mill Bay 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 Mill Bay — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Mill Bay — the short answer
Mill Bay, Alaska: USDA zone 7b, about 181 days between hard freezes, across 2K acres of town.
- USDA zone
- 7b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 19
- Kodiak Island Borough normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Oct 17
- Kodiak Island Borough normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~181
- Kodiak Island Borough normal — NOAA 1991–2020, nearest to this town
- Town area
- 2K 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 Kodiak Island Borough’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 7b is Mill Bay's average, not your lot's — a low corner or a tree line moves it. Against Mill Bay's 181-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Mill Bay
Each reading below is measured for Mill Bay itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsMill Bay runs about 181 days between hard freezes (read from Kodiak Island Borough, the closest normal to Mill Bay) — a moderate growing season.
There is room for the full run of cool-season crops plus a warm-season main crop, but the calendar is tight enough that a late spring or early fall frost still decides how much finishes.
Time warm-season transplants to your last hard freeze, and a few weeks of season extension turns a near-miss harvest into a sure one.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredMill Bay sits in USDA hardiness zone 7b.
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 Mill Bay
Every plant below cleared Mill Bay's own zone 7b and its 181-day season. Each card opens that plant's Alaska profile. How we score.
Is it too late to plant in Mill Bay?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Mar 22; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 19 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 17 — long-season crops need about 90 days of runway, quick greens only 30. Even past midsummer there is room for a true fall garden here, and garlic planted near the close carries the momentum into next year.
What's on the federal record near Mill Bay
Closest first, within ~10 miles of Mill Bay. Listing isn't leaking, and distance isn't exposure.
- St. Mary Catholic ChurchUnderground Storage Tanks · 1900 ft
- WALMART #2711Brownfields · 2000 ft
- BRECHAN ENTERPRISESBrownfields · 2100 ft
- ACS ENVIRONMENTAL SERVICESBrownfields · 2200 ft
- Brechan Enterprise Mill Bay ShopUnderground Storage Tanks · 2200 ft
- SAFEWAY STORE #1090Brownfields · 2300 ft
- Petro Express KodiakUnderground Storage Tanks · 2400 ft
- Mill Bay Gas & GoUnderground Storage Tanks · 2500 ft
- Glacier State TelcoUnderground Storage Tanks · 0.6 mi
- Kodiak Public WorksUnderground Storage Tanks · 0.6 mi
- Island AirUnderground Storage Tanks · 0.6 mi
- USCG - Loran A SitkinakUnderground Storage Tanks · 0.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Mill Bay'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 Mill Bay.
Total Sites
120
within ~10 miles of Mill Bay
Risk Level
Elevated
Highest-severity
3 Superfund sites (none NPL-listed)
Sources Checked
within ~10 miles of Mill Bay
Severity Distribution
within ~10 miles of Mill Bay
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Mill Bay, two things run higher than the national average within ~10 miles of Mill Bay — Superfund (3 sites) and Toxics Release Inventory (8 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Check your specific parcel in Mill Bay
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 Mill Bay average
Your land is one point inside Mill Bay
Everything above resolves to Mill Bay as a whole — one PHZM band, read across 2K acres, with hard-freeze dates borrowed from Kodiak Island 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 Mill Bay Average
Mill Bay Average
- ●USDA Zones 7b, averaged across Mill Bay
- ●One soil character for all of Mill Bay
- ●Frost dates read at Mill Bay's scale: Apr 19 to Oct 17
YOUR Parcel
- ✓Your exact zone, not Mill Bay's 7b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Mill Bay
Pull a site-specific report for your exact address in Mill Bay, Alaska — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Mill Bay averages can't show:
We read public map data around Mill Bay — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Mill Bay average
How we know this about Mill Bay
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 Kodiak Island 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 Mill Bay
When does frost risk typically end in Mill Bay?
The last hard freeze (28°F) in Mill Bay typically lands around Apr 19, 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 May 10.
When is the first frost in Mill Bay?
The first hard freeze (28°F) in Mill Bay typically arrives around Oct 17, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 3, so the watching starts about Sep 17 — about 181 days after the spring freeze cleared.
How long is the growing season in Mill Bay?
Measured between 28°F hard freezes, Mill Bay sees about 181 frost-free days — roughly Apr 19 through Oct 17, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 10 to Oct 3, about 146 days.
Is the soil safe to grow vegetables in Mill Bay?
The federal record around Mill Bay is a meaningful one — 120 documented sites, mostly Underground Storage Tanks entries (59), the nearest Underground Storage Tanks record about 0.4 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 I protect my plants from frost in Mill Bay?
From about Sep 17 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Oct 17 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Oct 17. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Mill Bay's scale — its 7b band and its 181-day season. Your yard writes its own version of Mill Bay'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 Mill Bay’s own scale
4 of the readings below were taken at Mill Bay's own scale — the 2,204 acres it covers and 120 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Mill Bay's own USDA hardiness band, zones 7bUSDA PHZM 2023
- 120 documented contamination sites on the federal record near Mill Bay, the closest Underground Storage Tanks record about 0.4 miles out from the town centreFederal environmental registers
- Mill Bay's boundary and the 2,204 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 7b and a ~181-day seasonGrowable Ground crop-matching engine
Inherited from a wider read
- The 28°F hard-freeze dates — Mill Bay has no normal of its own, so its county's is the closest measured readfrom Kodiak Island Borough
- Soil character — no town-scale survey exists, so Mill Bay's 2,204 acres read through its county's SSURGO summaryfrom Kodiak Island County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Kodiak Island 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 Kodiak Island County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Mill Bay's 2,204 acreswhy one lot differs from the next →
- Which side of Mill Bay you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 2,204 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.4 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 Mill Bay-wide figureread your own land →
More in Alaska
Wider growing context
What grows across AlaskaMill Bay sits outside our named growing regions, so Alaska as a whole is its closest context here.
Nearby growing guides