The Kenai Peninsula Coast spans USDA hardiness zones 4b-7a — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
Cook Inlet's maritime edge — from Homer's 6b banana-belt bluffs to Seward's 7a harbor, ocean-moderated pockets that garden far milder than the peninsula's interior river flats, on committed place records spanning 4b-7a. Reliable performers under these conditions include cabbage, potato, kale, and rhubarb; what your own ground favors still comes down to its soil, sun, and drainage.
The Kenai Peninsula Coast spans Alaska.
Your yard isn't all of the Kenai Peninsula Coast.
The Kenai Peninsula Coast spans USDA zones 4b-7a, but your parcel sits in exactly one — and slope, tree cover, and low spots nudge it further. 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 Kenai Peninsula Coast — soil, climate, flood, and parcel records. How we handle your address.
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The Kenai Peninsula Coast — the short answer
The Kenai Peninsula Coast: USDA zones 4b-7a, 150–176 frost-free days, in Alaska.
- USDA zones
- 4b-7a
- USDA PHZM 2023, aggregated over the footprint
- Frost-free season
- 150–176 days
- NOAA Regional Climate Centers ACIS, 1991-2020
- Towns
- 9
- US Census TIGER/Line 2025
- Region type
- Town cluster
- Growable Ground growing-region registry
Region boundary: Growable Ground growing-region registry — curated county clusters, EPA Level III ecoregions, and town clusters drawn finer than any county. Where a region publishes no measured season, no season figure is shown.
Hardiness Zone Range
What Grows in the Kenai Peninsula Coast
Plants matched to the Kenai Peninsula Coast's USDA zones 4b-7a, ordered by how much hardiness margin each has across the region — the ones with room to spare at both ends of this band lead. Each links to its full growing profile.
Native Plants of the Kenai Peninsula Coast
Plants the USDA PLANTS Database documents as native and present in this region’s state, kept only where the published hardiness range meets the Kenai Peninsula Coast’s USDA zones 4b-7a — closest range match first. Presence is recorded by state, so a plant can be documented across the state and still be scarce in your corner of the region.
The ground around the Kenai Peninsula Coast
The USDA soil survey maps this ground county by county. These are those records weighted by land area across the county containing the Kenai Peninsula Coast — the ground the Kenai Peninsula Coast sits in, read at the only grain the survey publishes.
In the county containing the Kenai Peninsula Coast, the ground is predominantly Spodosols, at 58% of mapped acres, followed by Histosols (25%), Entisols (8%) and Andisols (5%). Six soil orders appear in that record, which is the honest reason a regional soil answer only goes so far. The most extensive named soils are Starichkof, Strandline, and Spenard.
52% of those acres are well drained, and another 27% very poorly drained, 2% poorly drained. Topsoil pH runs 5.0–5.0 in that county’s own record.
Soil order
Spodosols
Drainage
Well drained
Topsoil pH
5.0–5.0
Hydric soils
41%
Soil changes across a driveway, so which of these your own ground sits on is a parcel question rather than a regional one. soil types explained.
USDA NRCS SSURGO via Soil Data Access
What this means for growing in the Kenai Peninsula Coast
The soil survey reads this ground county by county, and the readings above are the record for the county containing the Kenai Peninsula Coast. Here is what they mean for a garden here — and the move an experienced grower makes about each one.
Drainage
From county records52% of the mapped acres across the county containing the Kenai Peninsula Coast are well drained — ground that drains quickly. The survey maps this ground county-wide, so it describes the setting the Kenai Peninsula Coast sits in rather than the valley floor alone.
The upside is soil you can work early in spring and roots that never drown; the cost is that fast-draining ground dries out fast and leaches nutrients away before plants can use them.
Work in compost and mulch to hold moisture and feed, and water more often in short doses than deep and rarely.
USDA NRCS SSURGO
Surface pH
From county recordsTopsoil across the county containing the Kenai Peninsula Coast runs pH 5.0 — acidic in the one record covering it.
Blueberries, potatoes, and rhododendrons thrive in it, but most vegetables start locking out nutrients below about pH 6.0 and grow pale and stunted no matter how much you feed them.
A measured lime application raises pH for the crops that need it — but test first, because the right rate depends on your own soil, not the county average.
USDA NRCS SSURGO
Wet ground
From county recordsAbout 41% of the ground across the county containing the Kenai Peninsula Coast is mapped as hydric — wetland — soil.
If your lot falls in one of those pockets, a standard in-ground bed will fight waterlogging all season, and roots that need air will struggle.
Check how your own ground drains before you dig; raised beds or moisture-loving plantings turn a wet corner from a problem into a niche.
USDA NRCS SSURGO
Safe to Grow Here?
What the federal record shows across the Kenai Peninsula Coast — and how to grow with it.
Across Kenai Peninsula County, which contains the Kenai Peninsula Coast, the federal record holds 1,107 documented sites, mostly Nitrate (500), Underground Storage Tanks (266) and Brownfields (169).
That is the containing county's count — this region is a smaller piece of that ground, so it is context, not a reading of any one lot. Open the map outlined to the Kenai Peninsula Coast to see which records sit where you actually grow.
Sources Checked
Summed across the county containing the Kenai Peninsula Coast
A note from Gnorman
What an experienced grower watches for around here
In and around the Kenai Peninsula Coast, two things run higher than the national average across the county containing the Kenai Peninsula Coast — Mining (153 sites) and Nitrate (500 sites). It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
Nitrate: Nitrate contamination primarily comes from agricultural fertilizer runoff and failing septic systems.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Test well water for nitrate if you rely on a private well for irrigation (EPA standard: 10 mg/L).
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
Your land is one point inside the Kenai Peninsula Coast
Everything above resolves to the Kenai Peninsula Coast as a whole — a footprint spanning USDA zones 4b-7a. Your parcel sits in exactly one of them. 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 region 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 regional average.
Your Lot vs the Kenai Peninsula Coast Average
Kenai Peninsula Coast Average
- ●USDA Zones 4b-7a, averaged across Kenai Peninsula Coast
- ●One soil character for all of Kenai Peninsula Coast
- ●State-average frost dates
YOUR Parcel
- ✓Your exact zone, not Kenai Peninsula Coast's 4b-7a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in the Kenai Peninsula Coast
Pull a site-specific report for your exact address in the Kenai Peninsula Coast — soil, sun, drainage, frost risk, contamination, and scored plant recommendations.
Three things about your lot that Kenai Peninsula Coast averages can't show:
We read public map data around The Kenai Peninsula Coast — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Kenai Peninsula Coast average
How we know this about the Kenai Peninsula Coast
The boundary: the region's own towns — a footprint finer than any county, because the county average would misread this microclimate. Growing regions have no official boundary, so this footprint is our published one, and every figure on this page was measured over the towns inside it rather than borrowed from the state around it.
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, aggregated across the footprint; the growing season from NOAA Regional Climate Centers ACIS 1991–2020 28°F normals, read at each member’s own record; boundaries from US Census TIGER/Line 2025; the contamination record from the federal sources named in that beat above; the soil from the USDA NRCS SSURGO survey, read at each member county’s own record and weighted to this footprint by land area. Where a member carries no record of its own, it is absent from the figure rather than filled in.
Common questions about the Kenai Peninsula Coast
What hardiness zone is the Kenai Peninsula Coast?
The Kenai Peninsula Coast spans USDA hardiness zones 4b-7a, aggregated from the USDA Agricultural Research Service Plant Hardiness Zone Map 2023 across the region's own towns. Zones reflect average annual extreme minimum temperatures from 1991–2020 data.
How long is the growing season in the Kenai Peninsula Coast?
Measured between 28°F hard freezes, the Kenai Peninsula Coast's towns mostly run 152 to 170 frost-free days, median 164 (NOAA Regional Climate Centers ACIS, 1991–2020, over 9 member towns). That 18-day spread is the honest read — no single season describes 9 towns, and each town guide below carries its own.
When does frost risk end in the Kenai Peninsula Coast?
Across the Kenai Peninsula Coast, the middle half of member towns see their last 28°F hard freeze between Apr 23 and May 1 (median Apr 26), and their first fall freeze between Sep 30 and Oct 10. Those are hard freezes, not the last light frost: tender transplants wait for about May 17, and elevation decides which end of a 8-day spread you garden in.
What grows well in the Kenai Peninsula Coast?
The Kenai Peninsula Coast's conditions suit plants such as Cabbage, Potato, Kale, Rhubarb, Sitka Spruce. What actually thrives on any one site still turns on its specific soil, sun, and drainage — we score each plant against the real conditions at your address.
How is the Kenai Peninsula Coast defined?
The Kenai Peninsula Coast is a true microclimate — smaller than the county that contains it, with a growing reality of its own. So this page is built from the region's own 9 towns, each carrying its own hardiness zone and frost record, rather than from a county average measured somewhere else.
Which states does the Kenai Peninsula Coast cover?
The Kenai Peninsula Coast spans Alaska. Each state's full growing guide is linked on this page.
What other growing regions cover the same states?
Southeast Alaska / Inside Passage Panhandle, Interior Alaska / Tanana Valley (Fairbanks), and Matanuska–Susitna Valley (Mat-Su) share at least one state with the Kenai Peninsula Coast. Growing regions overlap and interlock — a single address can sit inside more than one, which is why the precise read is always the parcel, not the region.
What this page reads at the Kenai Peninsula Coast’s own scale
6 of the readings below were taken at the Kenai Peninsula Coast's own scale — the zone 4b-7a band across its footprint, a median 164-day season across its 9 towns and 1,107 documented federal contamination records across its one county, 1,107 of them in Kenai Peninsula County alone; one is borrowed from a wider read, named and linked below.
Measured here
- The USDA hardiness band 4b-7a aggregated across all 9 towns in the footprintUSDA PHZM 2023
- The boundary itself — the 9 towns this region is curated fromGrowable Ground subregion registry
- The growing character that makes this region distinct from the states it crossesGrowable Ground subregion registry
- The 28°F season across the footprint — the middle half of its 9 towns run 152 to 170 frost-free days, median 164NOAA Regional Climate Centers ACIS, 1991-2020
- The federal contamination record over the whole footprint — 1,107 documented federal contamination records across its one county, 1,107 of them in Kenai Peninsula County aloneEPA, USGS and USDA federal site records
- The soil order mix across the footprint — 58% Spodosols, topsoil pH 5.0–5.0, area-weighted across its one mapped countyUSDA NRCS SSURGO
Inherited from a wider read
- The candidate plant list — its state's curated sets, merged and filtered to zones 4b-7afrom Alaska
What this page can’t tell you
- Which end of the 18-day range your ground sits at — 152 days at one extreme, 170 at the other, decided mostly by elevationfrost dates explained →
- Which of those soils your own ground sits on — the survey maps them county-wide, and they change across a drivewaysoil types explained →
- The soil pH, drainage, sun hours, and frost pockets on one specific lotwhy one lot differs from the next →
Explore the Kenai Peninsula Coast
State growing guides
Towns in this region
The county containing this region
Other growing regions across Alaska
Alaska's temperate rainforest inverts the usual Alaska problem: the constraint here isn't cold, it's a lack of summer heat. The Inside Passage panhandle spans USDA zones 5a–8a overall — 7a–8a in the coastal towns where nearly all of its gardening happens (Sitka 8a, Ketchikan 7b) with a 159–240 day frost-free season — longer than much of the mountain West — yet cloudy, cool, extremely wet maritime summers on acidic, boggy Tongass soils mean heat-lovers like tomatoes and corn stall out while cool-season greens, brassicas, potatoes, rhubarb, and berries thrive. This is the mirror image of Alaska's cold-but-sunny Interior and cannot share a page with it.
Interior Alaska grows on a knife-edge no other American garden shares: a continental cold pocket where winters bottom out near -40F and the region spans zone 1b-4a, its inhabited Tanana floor running roughly 1b-2b — among the coldest settled hardiness zones in the country — yet Fairbanks summers deliver up to ~21 hours of daylight. That midnight sun is the trade: cold-hardy, quick-maturing varieties sprint through an ~85-118 day frost-free window (as short as 85 days out toward Delta Junction and Tok). Success here is a distinct discipline built on high tunnels, short-season cultivars, and exploiting long light — nothing about it resembles the maritime panhandle or the milder Mat-Su, and the coarse state page (a flat 3a-4b) cannot express a 1b-4a region whose settled floor sits at the cold end of that band on a ~90-day season.
Alaska's farm heartland — the Mat-Su's long June days grow the state fair's giant cabbages on a 4a-5b valley floor whose committed band runs two zones warmer than the borough's glacier-to-Denali average.