Diamond Ridge, Alaska, sits in USDA hardiness zone 6a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
The conditions favor cabbage, blackberry, california poppy, and collard greens, among others — though every individual site edits that list with its own soil, sun, and drainage.
Even in Diamond Ridge, 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 Diamond Ridge 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 Diamond Ridge — soil, climate, flood, and parcel records. How we handle your address.
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Diamond Ridge — the short answer
Diamond Ridge, Alaska: USDA zone 6a, about 148 days between hard freezes, across 27K acres of town.
- USDA zone
- 6a
- 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
- 27K 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 6a is Diamond Ridge's average, not your lot's — a low corner or a tree line moves it. Against Diamond Ridge's 148-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Diamond Ridge
Each reading below is measured for Diamond Ridge itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsDiamond Ridge runs about 148 days between hard freezes (read from Kenai Peninsula Borough, the closest normal to Diamond Ridge) — 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
MeasuredDiamond Ridge sits in USDA hardiness zone 6a.
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 Diamond Ridge
Every plant below cleared Diamond Ridge's own zone 6a and its 148-day season. Each card opens that plant's Alaska profile. How we score.
Is it too late to plant in Diamond Ridge?
Rarely: the season closes in stages, not all at once, and each stage has its crops. 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 Diamond Ridge
Closest first, within ~10 miles of Diamond Ridge. Listing isn't leaking, and distance isn't exposure.
- SC00501329CACA2 001Nitrate · 1.0 mi
- SC00501329CACA1 001Nitrate · 1.0 mi
- SC00601306DDDD1 001Nitrate · 1.5 mi
- SC00601308BBBA1 005Nitrate · 1.7 mi
- SC00601308BBAB2 006Nitrate · 1.7 mi
- SC00601412CAAB1 001Nitrate · 2.4 mi
- Diamond RidgeUnderground Storage Tanks · 2.6 mi
- SC00601402CCAA1 001Nitrate · 2.8 mi
- SC00601318DDBB1 001Nitrate · 3.4 mi
- South Peninsula HospitalUnderground Storage Tanks · 3.4 mi
- SC00601316ACAD1 015Nitrate · 3.6 mi
- Homer High SchoolUnderground Storage Tanks · 3.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Diamond Ridge'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 Diamond Ridge.
Total Sites
126
within ~10 miles of Diamond Ridge
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Diamond Ridge
Severity Distribution
within ~10 miles of Diamond Ridge
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Diamond Ridge, Nitrate runs higher than the national average — 58 sites within ~10 miles of Diamond Ridge. 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 Diamond Ridge
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 Diamond Ridge average
Your land is one point inside Diamond Ridge
Everything above resolves to Diamond Ridge as a whole — one PHZM band, read across 27K 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 Diamond Ridge Average
Diamond Ridge Average
- ●USDA Zones 6a, averaged across Diamond Ridge
- ●One soil character for all of Diamond Ridge
- ●Frost dates read at Diamond Ridge's scale: May 2 to Sep 27
YOUR Parcel
- ✓Your exact zone, not Diamond Ridge's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Diamond Ridge
Pull a site-specific report for your exact address in Diamond Ridge, Alaska — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Diamond Ridge averages can't show:
We read public map data around Diamond Ridge — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Diamond Ridge average
How we know this about Diamond Ridge
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 Diamond Ridge
When does frost risk typically end in Diamond Ridge?
The last hard freeze (28°F) in Diamond Ridge 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 Diamond Ridge?
The first hard freeze (28°F) in Diamond Ridge 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 Diamond Ridge?
Measured between 28°F hard freezes, Diamond Ridge 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 Diamond Ridge?
The federal record around Diamond Ridge is a meaningful one — 126 documented sites, mostly Nitrate entries (58), the nearest Nitrate record about 1.0 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 gardeners stretch the season in Diamond Ridge?
With about 148 frost-free days between hard freezes, Diamond Ridge 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 Diamond Ridge's scale — its 6a band and its 148-day season. Your yard writes its own version of Diamond Ridge'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 Diamond Ridge’s own scale
4 of the readings below were taken at Diamond Ridge's own scale — the 27,135 acres it covers and 126 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Diamond Ridge's own USDA hardiness band, zones 6aUSDA PHZM 2023
- 126 documented contamination sites on the federal record near Diamond Ridge, the closest Nitrate record about 1.0 miles out from the town centreFederal environmental registers
- Diamond Ridge's boundary and the 27,135 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~148-day seasonGrowable Ground crop-matching engine
Inherited from a wider read
- The 28°F hard-freeze dates — Diamond Ridge 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 Diamond Ridge's 27,135 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 Diamond Ridge's 27,135 acreswhy one lot differs from the next →
- Which side of Diamond Ridge you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 27,135 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate 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 Diamond Ridge-wide figureread your own land →
More in Alaska
Wider growing context
What grows across AlaskaDiamond Ridge sits outside our named growing regions, so Alaska as a whole is its closest context here.
Nearby growing guides