Port Graham, Alaska, sits in USDA hardiness zone 6b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Among the crops suited to this profile: cabbage, blackberry, california poppy, and collard greens. The site-level story — soil, sun, drainage — decides the rest.
Even in Port Graham, 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 Port Graham 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 Port Graham — soil, climate, flood, and parcel records. How we handle your address.
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Port Graham — the short answer
Port Graham, Alaska: USDA zone 6b, about 148 days between hard freezes, across 4K acres of town.
- USDA zone
- 6b
- 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
- 4K 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 6b is Port Graham's average, not your lot's — a low corner or a tree line moves it. Against Port Graham's 148-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Port Graham
Each reading below is measured for Port Graham itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsPort Graham runs about 148 days between hard freezes (read from Kenai Peninsula Borough, the closest normal to Port Graham) — 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
MeasuredPort Graham sits in USDA hardiness zone 6b.
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 Port Graham
Every plant below cleared Port Graham's own zone 6b and its 148-day season. Each card opens that plant's Alaska profile. How we score.
Is it too late to plant in Port Graham?
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. Short seasons reward decisiveness — quick-maturing varieties late, hardy greens under cover, and next year’s garlic in the ground before it closes.
What's on the federal record near Port Graham
Closest first, within ~10 miles of Port Graham. Listing isn't leaking, and distance isn't exposure.
- SC00901533CBCC1 001Nitrate · 0.9 mi
- KENAI PENINSULA BOROUGH PORT GRAHAM LDFLBrownfields · 0.9 mi
- SnowMining · 6.5 mi
- Susan B. English Elementary/high SchoolUnderground Storage Tanks · 8.2 mi
- City Of SeldoviaUnderground Storage Tanks · 8.2 mi
- Small Boat HarborUnderground Storage Tanks · 8.2 mi
- Seldovia CanneryUnderground Storage Tanks · 8.3 mi
- Fish Creek Pump StationUnderground Storage Tanks · 8.6 mi
- Homer Electric Assoc.Underground Storage Tanks · 8.7 mi
- Claim PointMining · 9.0 mi
- ReefMining · 9.0 mi
Measured from Port Graham'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 Port Graham.
Sources Checked
within ~10 miles of Port Graham
Severity Distribution
within ~10 miles of Port Graham
Highest-Severity Sites
Know Before You Grow
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •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.
Check your specific parcel in Port Graham
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 Port Graham average
Your land is one point inside Port Graham
Everything above resolves to Port Graham as a whole — one PHZM band, read across 4K 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 Port Graham Average
Port Graham Average
- ●USDA Zones 6b, averaged across Port Graham
- ●One soil character for all of Port Graham
- ●Frost dates read at Port Graham's scale: May 2 to Sep 27
YOUR Parcel
- ✓Your exact zone, not Port Graham's 6b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Port Graham
Pull a site-specific report for your exact address in Port Graham, Alaska — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Port Graham averages can't show:
We read public map data around Port Graham — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Port Graham average
How we know this about Port Graham
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 Port Graham
When does frost risk typically end in Port Graham?
The last hard freeze (28°F) in Port Graham 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 Port Graham?
The first hard freeze (28°F) in Port Graham 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 Port Graham?
Measured between 28°F hard freezes, Port Graham 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 Port Graham?
The federal record around Port Graham is light — 13 documented sites across the 9 federal source types we checked, mostly Underground Storage Tanks entries (6), the nearest Nitrate record about 0.9 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 Port Graham?
With about 148 frost-free days between hard freezes, Port Graham 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 Port Graham's scale — its 6b band and its 148-day season. Your yard writes its own version of Port Graham'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 Port Graham’s own scale
4 of the readings below were taken at Port Graham's own scale — the 4,092 acres it covers and 13 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Port Graham's own USDA hardiness band, zones 6bUSDA PHZM 2023
- 13 documented contamination sites on the federal record near Port Graham, the closest Nitrate record about 0.9 miles out from the town centreFederal environmental registers
- Port Graham's boundary and the 4,092 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6b and a ~148-day seasonGrowable Ground crop-matching engine
Inherited from a wider read
- The 28°F hard-freeze dates — Port Graham 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 Port Graham's 4,092 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 Port Graham's 4,092 acreswhy one lot differs from the next →
- Which side of Port Graham you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 4,092 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 0.9 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 Port Graham-wide figureread your own land →
More in Alaska
Wider growing context
What grows across AlaskaPort Graham sits outside our named growing regions, so Alaska as a whole is its closest context here.
Nearby growing guides