Kasilof, 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.
These conditions suit cabbage, cranberry, cilantro, and collard greens — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Even in Kasilof, 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 Kasilof 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 Kasilof — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Kasilof — the short answer
Kasilof, Alaska: USDA zone 4b, about 148 days between hard freezes, across 7K acres of town.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 2
- Kenai Peninsula Borough normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Sep 27
- Kenai Peninsula Borough normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~148
- Kenai Peninsula Borough normal — NOAA 1991–2020, nearest to this town
- Town area
- 7K 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 Kenai Peninsula Borough’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 4b is Kasilof's average, not your lot's — a low corner or a tree line moves it. Against Kasilof's 148-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Kasilof
Each reading below is measured for Kasilof itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsKasilof runs about 148 days between hard freezes (read from Kenai Peninsula Borough, the closest normal to Kasilof) — 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
MeasuredKasilof 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 Kasilof
Every plant below cleared Kasilof's own zone 4b and its 148-day season. Each card opens that plant's Alaska profile. How we score.
Is it too late to plant in Kasilof?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Apr 4; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 2 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 27 — 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.
What's on the federal record near Kasilof
Closest first, within ~10 miles of Kasilof. Listing isn't leaking, and distance isn't exposure.
- Kasilof Riverview LodgeUnderground Storage Tanks · 1.0 mi
- SB00301131BDCC1 001Nitrate · 1.3 mi
- SB00301213ADDD1 001Nitrate · 2.6 mi
- SB00301118BBAD1 001Nitrate · 2.8 mi
- SB00301104CDCC1 003Nitrate · 3.8 mi
- SB00301104BBBC1 006Nitrate · 4.6 mi
- SB00301201BDAD2 001Nitrate · 4.6 mi
- SB00201210BCDB1 001Nitrate · 5.0 mi
- TJ Seggy'sUnderground Storage Tanks · 6.2 mi
- SB00401225CBAA1 001Nitrate · 6.4 mi
- Kenai Supply, Inc.Underground Storage Tanks · 6.4 mi
- SOLDOTNAPFAS · 7.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Kasilof'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 Kasilof.
Sources Checked
within ~10 miles of Kasilof
Severity Distribution
within ~10 miles of Kasilof
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Kasilof, Nitrate runs higher than the national average — 26 sites within ~10 miles of Kasilof. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Check your specific parcel in Kasilof
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 Kasilof average
Your land is one point inside Kasilof
Everything above resolves to Kasilof as a whole — one PHZM band, read across 7K acres, with hard-freeze dates borrowed from Kenai Peninsula 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 Kasilof Average
Kasilof Average
- ●USDA Zones 4b, averaged across Kasilof
- ●One soil character for all of Kasilof
- ●Frost dates read at Kasilof's scale: May 2 to Sep 27
YOUR Parcel
- ✓Your exact zone, not Kasilof's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Kasilof
Pull a site-specific report for your exact address in Kasilof, Alaska — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Kasilof averages can't show:
We read public map data around Kasilof — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Kasilof average
How we know this about Kasilof
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 Kenai Peninsula 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 Kasilof
When does frost risk typically end in Kasilof?
The last hard freeze (28°F) in Kasilof typically lands around May 2, 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 23.
When is the first frost in Kasilof?
The first hard freeze (28°F) in Kasilof typically arrives around Sep 27, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 13, so the watching starts about Aug 28 — about 148 days after the spring freeze cleared.
How long is the growing season in Kasilof?
Measured between 28°F hard freezes, Kasilof sees about 148 frost-free days — roughly May 2 through Sep 27, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 23 to Sep 13, about 113 days.
Is the soil safe to grow vegetables in Kasilof?
The federal record around Kasilof shows 32 documented sites, mostly Nitrate entries (26), the nearest Underground Storage Tanks record about 1.0 miles out — a typical footprint for a growing area, and proximity to a documented site is information, not a diagnosis of any one yard. It's worth seeing which recorded sites sit closest to where you grow, and testing the soil before new food beds near any of them.
How do gardeners stretch the season in Kasilof?
With about 148 frost-free days between hard freezes, Kasilof 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 176 to 204 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 2 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Kasilof's scale — its 4b band and its 148-day season. Your yard writes its own version of Kasilof'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 Kasilof’s own scale
4 of the readings below were taken at Kasilof's own scale — the 6,672 acres it covers and 32 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Kasilof's own USDA hardiness band, zones 4bUSDA PHZM 2023
- 32 documented contamination sites on the federal record near Kasilof, the closest Underground Storage Tanks record about 1.0 miles out from the town centreFederal environmental registers
- Kasilof's boundary and the 6,672 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~148-day seasonGrowable Ground crop-matching engine
Inherited from a wider read
- The 28°F hard-freeze dates — Kasilof has no normal of its own, so its county's is the closest measured readfrom Kenai Peninsula Borough
- Soil character — no town-scale survey exists, so Kasilof's 6,672 acres read through its county's SSURGO summaryfrom Kenai Peninsula County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Kenai Peninsula 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 Kenai Peninsula County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Kasilof's 6,672 acreswhy one lot differs from the next →
- Which side of Kasilof you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 6,672 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 1.0 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 Kasilof-wide figureread your own land →
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