Black Hawk, Colorado, sits in USDA hardiness zone 5b — a zone band wide enough that plant choice, not possibility, is the interesting question.
Well-matched crops include cabbage, cranberry, lavender, and collard greens, and the gap between "grows in the area" and "grows in your yard" is closed by soil, sun, and drainage.
Even in Black Hawk, 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 Hawk 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 Hawk — soil, climate, flood, and parcel records. How we handle your address.
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Black Hawk — the short answer
Black Hawk, Colorado: USDA zone 5b, about 138 days between hard freezes, across 2K acres of city.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 15
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Sep 30
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~138
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 2K 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 5b is Black Hawk's average, not your lot's — a low corner or a tree line moves it. Against Black Hawk's 138-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Black Hawk
Each reading below is measured for Black Hawk itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredBlack Hawk runs about 138 days between hard freezes — 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
MeasuredBlack Hawk sits in USDA hardiness zone 5b.
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 Hawk is in
Black Hawk sits in the Southern Rockies — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at Black Hawk's own centroid rather than borrowed from Gilpin County.
What Grows in Black Hawk
Every plant below cleared Black Hawk's own zone 5b and its 138-day season. Each card opens that plant's Colorado profile. How we score.
Is it too late to plant in Black Hawk?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Apr 17; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 15 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 30 — long-season crops need about 90 days of runway, quick greens only 30. In a season this compact, fast finishers and cold-hardy greens do the late work, and garlic tucked in before the freeze repays you next summer.
What's on the federal record near Black Hawk
Closest first, within ~10 miles of Black Hawk. Listing isn't leaking, and distance isn't exposure.
- Mill Site #29Underground Storage Tanks · 25 ft
- Kwik MartUnderground Storage Tanks · 200 ft
- After SupperMining · 550 ft
- Black Hawk ConocoUnderground Storage Tanks · 650 ft
- SpecieMining · 1000 ft
- BobtailMining · 1500 ft
- Golden GilpinMining · 2000 ft
- Gasten MineMining · 2100 ft
- HopeMining · 2200 ft
- Becker-BatesMining · 2400 ft
- Blackhawk DistrictMining · 0.5 mi
- HunterMining · 0.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Black Hawk'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 Hawk.
Sources Checked
within ~10 miles of Black Hawk
Severity Distribution
within ~10 miles of Black Hawk
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Black Hawk, Mining runs higher than the national average — 600 sites within ~10 miles of Black Hawk. 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.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Check your specific parcel in Black Hawk
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 Hawk average
Your land is one point inside Black Hawk
Everything above resolves to Black Hawk as a whole — one PHZM band and one 28°F frost record, read across 2K 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 Hawk Average
Black Hawk Average
- ●USDA Zones 5b, averaged across Black Hawk
- ●One soil character for all of Black Hawk
- ●Frost dates read at Black Hawk's scale: May 15 to Sep 30
YOUR Parcel
- ✓Your exact zone, not Black Hawk's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Black Hawk
Pull a site-specific report for your exact address in Black Hawk, Colorado — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Black Hawk averages can't show:
We read public map data around Black Hawk — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Black Hawk average
How we know this about Black Hawk
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 Hawk’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 Hawk
When does frost risk typically end in Black Hawk?
The last hard freeze (28°F) in Black Hawk typically lands around May 15, 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 Jun 5.
When is the first frost in Black Hawk?
The first hard freeze (28°F) in Black Hawk typically arrives around Sep 30, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 16, so the watching starts about Aug 31 — about 138 days after the spring freeze cleared.
How long is the growing season in Black Hawk?
Measured between 28°F hard freezes, Black Hawk sees about 138 frost-free days — roughly May 15 through Sep 30, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 5 to Sep 16, about 103 days.
Is the soil safe to grow vegetables in Black Hawk?
The federal record around Black Hawk runs heavier than most — 677 documented sites, mostly Mining entries (600), the nearest Underground Storage Tanks record under a tenth of a mile out — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
How do gardeners stretch the season in Black Hawk?
With about 138 frost-free days between hard freezes, Black Hawk 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 166 to 194 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 15 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Black Hawk's scale — its 5b band and its 138-day season. Your yard writes its own version of Black Hawk'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 Hawk’s own scale
6 of the readings below were taken at Black Hawk's own scale — its own ~138-day season between 28°F freezes, the 1,997 acres it covers and 677 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Black Hawk's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Black Hawk's own 28°F hard-freeze dates, about May 15 and Sep 30 and the ~138-day span between themNOAA 1991–2020 Climate Normals
- 677 documented contamination sites on the federal record near Black Hawk, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Black Hawk's boundary and the 1,997 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~138-day seasonGrowable Ground crop-matching engine
- The ecoregion at Black Hawk's own centroid, the Southern RockiesUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Black Hawk's 1,997 acres read through its county's SSURGO summaryfrom Gilpin County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Gilpin County
- The growing challenges every Colorado grower plans around — written at state scale, so they stay on the state guidefrom Colorado
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Gilpin County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Black Hawk's 1,997 acreswhy one lot differs from the next →
- Which side of Black Hawk you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,997 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record under a tenth of a mile 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 Hawk-wide figureread your own land →