Black Diamond, Washington, sits in USDA hardiness zone 8b — a zone band wide enough that plant choice, not possibility, is the interesting question.
Among the crops suited to this profile: cabbage, fig, california poppy, and collard greens. The site-level story — soil, sun, drainage — decides the rest.
Even in Black Diamond, 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 Black Diamond 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 Black Diamond — soil, climate, flood, and parcel records. How we handle your address.
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Black Diamond — the short answer
Black Diamond, Washington: USDA zone 8b, about 281 days between hard freezes, across 4K acres of city.
- USDA zone
- 8b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Feb 16
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Nov 24
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~281
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 4K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are this town’s own 28°F normals: light frosts run a few weeks past them, and tender transplants usually wait 2–3 weeks after the last hard freeze.
Hardiness Zone Range
Zone 8b is Black Diamond's average, not your lot's — a low corner or a tree line moves it. Against Black Diamond's 281-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Black Diamond
Each reading below is measured for Black Diamond itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredBlack Diamond runs about 281 days between hard freezes — close to year-round growing.
Frost is rarely the limit here; winter plantings are as real as summer ones, and the harder question is which crops shrug off the summer heat.
Grow cool-season crops through the mild winter, and choose heat-tolerant varieties for the summer beds.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredBlack Diamond sits in USDA hardiness zone 8b.
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
The kind of country Black Diamond is in
Black Diamond sits in the Puget Lowland — EPA Level III, inside the wider Marine West Coast Forest. That is read at Black Diamond's own centroid rather than borrowed from King County.
What Grows in Black Diamond
Every plant below cleared Black Diamond's own zone 8b and its 281-day season. Each card opens that plant's Washington profile. How we score.
Is it too late to plant in Black Diamond?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Jan 19; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Feb 16 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Nov 24 — long-season crops need about 90 days of runway, quick greens only 30. And with a calendar this mild, the honest answer is that planting barely stops — winter opens seasons colder regions never see.
What's on the federal record near Black Diamond
Closest first, within ~10 miles of Black Diamond. Listing isn't leaking, and distance isn't exposure.
- BLACK DIAMOND AUTOMOTIVEUnderground Storage Tanks · 0.6 mi
- PALMER COKING COAL CO TERRY MORRISUnderground Storage Tanks · 0.6 mi
- BLACK DIAMOND DISCOUNT AUTOUnderground Storage Tanks · 0.6 mi
- 76 FOOD MARTUnderground Storage Tanks · 0.6 mi
- Black DiamondMining · 0.7 mi
- TRM WOOD PRODUCTS CO INCUnderground Storage Tanks · 0.8 mi
- CHS NORTHWESTUnderground Storage Tanks · 0.8 mi
- ASSOCIATED PETROLEUM PRODUCTS INCUnderground Storage Tanks · 0.8 mi
- WANDA KRYSKOUnderground Storage Tanks · 1.4 mi
- CADMAN BLACK DIAMOND INCBrownfields · 2.0 mi
- FLINTSTONE SAND & GRAVEL INCUnderground Storage Tanks · 2.2 mi
- 21N/06E-04B08 SWQA11Nitrate · 2.3 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Black Diamond'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 Black Diamond.
Sources Checked
within ~10 miles of Black Diamond
Severity Distribution
within ~10 miles of Black Diamond
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Black Diamond, two things run higher than the national average within ~10 miles of Black Diamond — CAFO (7 sites) and Underground Storage Tanks (311 sites). That's not a problem with your land — it's information about it.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Black Diamond
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 Black Diamond average
Your land is one point inside Black Diamond
Everything above resolves to Black Diamond as a whole — one PHZM band and one 28°F frost record, read across 4K acres. 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 city 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 Black Diamond Average
Black Diamond Average
- ●USDA Zones 8b, averaged across Black Diamond
- ●One soil character for all of Black Diamond
- ●Frost dates read at Black Diamond's scale: Feb 16 to Nov 24
YOUR Parcel
- ✓Your exact zone, not Black Diamond's 8b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Black Diamond
Pull a site-specific report for your exact address in Black Diamond, Washington — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Black Diamond averages can't show:
We read public map data around Black Diamond — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Black Diamond average
How we know this about Black Diamond
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Black Diamond’s own record; 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 city grain anywhere on this page — there is no city-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 Black Diamond
When does frost risk typically end in Black Diamond?
The last hard freeze (28°F) in Black Diamond typically lands around Feb 16, 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 Mar 9.
When is the first frost in Black Diamond?
The first hard freeze (28°F) in Black Diamond typically arrives around Nov 24, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 10, so the watching starts about Oct 25 — about 281 days after the spring freeze cleared.
How long is the growing season in Black Diamond?
Measured between 28°F hard freezes, Black Diamond sees about 281 frost-free days — roughly Feb 16 through Nov 24, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Mar 9 to Nov 10, about 246 days.
Is the soil safe to grow vegetables in Black Diamond?
The federal record around Black Diamond is a meaningful one — 473 documented sites, mostly Underground Storage Tanks entries (311), the nearest Underground Storage Tanks record about 0.6 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 Black Diamond?
From about Oct 25 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 Nov 24 (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 Nov 24. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Black Diamond's scale — its 8b band and its 281-day season. Your yard writes its own version of Black Diamond'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 Black Diamond’s own scale
6 of the readings below were taken at Black Diamond's own scale — its own ~281-day season between 28°F freezes, the 4,223 acres it covers and 473 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Black Diamond's own USDA hardiness band, zones 8bUSDA PHZM 2023
- Black Diamond's own 28°F hard-freeze dates, about Feb 16 and Nov 24 and the ~281-day span between themNOAA 1991–2020 Climate Normals
- 473 documented contamination sites on the federal record near Black Diamond, the closest Underground Storage Tanks record about 0.6 miles out from the town centreFederal environmental registers
- Black Diamond's boundary and the 4,223 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 8b and a ~281-day seasonGrowable Ground crop-matching engine
- The ecoregion at Black Diamond's own centroid, the Puget LowlandUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Black Diamond's 4,223 acres read through its county's SSURGO summaryfrom King County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom King County
- The growing challenges every Washington grower plans around — written at state scale, so they stay on the state guidefrom Washington
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom King County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Black Diamond's 4,223 acreswhy one lot differs from the next →
- Which side of Black Diamond you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 4,223 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.6 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 Black Diamond-wide figureread your own land →