Boulder Canyon, South Dakota, sits in USDA hardiness zone 5b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Growers here do well with cabbage, cranberry, lavender, and collard greens — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Even in Boulder Canyon, 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 Boulder Canyon 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 Boulder Canyon — soil, climate, flood, and parcel records. How we handle your address.
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Boulder Canyon — the short answer
Boulder Canyon, South Dakota: USDA zone 5b, about 153 days between hard freezes, across 2K acres of town.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 7
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 7
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~153
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town 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 Boulder Canyon's average, not your lot's — a low corner or a tree line moves it. Against Boulder Canyon's 153-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Boulder Canyon
Each reading below is measured for Boulder Canyon itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredBoulder Canyon runs about 153 days between hard freezes — a moderate growing season.
There is room for the full run of cool-season crops plus a warm-season main crop, but the calendar is tight enough that a late spring or early fall frost still decides how much finishes.
Time warm-season transplants to your last hard freeze, and a few weeks of season extension turns a near-miss harvest into a sure one.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredBoulder Canyon 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 Boulder Canyon is in
Boulder Canyon sits in the Middle Rockies — EPA Level III, inside the wider Northwestern Forested Mountains. That is read at Boulder Canyon's own centroid rather than borrowed from Lawrence County.
What Grows in Boulder Canyon
Every plant below cleared Boulder Canyon's own zone 5b and its 153-day season. Each card opens that plant's South Dakota profile. How we score.
Is it too late to plant in Boulder Canyon?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Apr 9; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 7 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 7 — long-season crops need about 90 days of runway, quick greens only 30. The tail of the season still works: sixty-day crops into late summer, quick greens after, garlic last of all.
What's on the federal record near Boulder Canyon
Closest first, within ~10 miles of Boulder Canyon. Listing isn't leaking, and distance isn't exposure.
- 005N04E15ACBBNitrate · 1.2 mi
- 005N04E27ACDCNitrate · 2.2 mi
- 005N04E01ABBD(LA86C)Nitrate · 2.6 mi
- BAR-STO PRECISION MACHINE, LLCBrownfields · 2.7 mi
- BLACK HILLS MANUFACTURING SERVICES INC.Brownfields · 2.8 mi
- DAKOTA ARMSToxics Release Inventory · 2.8 mi
- 005N05E07ANitrate · 2.9 mi
- UNITED PARCEL SERVICE - STURGISBrownfields · 3.1 mi
- 005N05E05CCNitrate · 3.4 mi
- 005N05E05BBCBNitrate · 3.5 mi
- INTERNATIONAL PAPER CO. - WHEELER LUMBER SITEBrownfields · 3.5 mi
- 005N05E08DDBDNitrate · 3.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Boulder Canyon'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 Boulder Canyon.
Sources Checked
within ~10 miles of Boulder Canyon
Severity Distribution
within ~10 miles of Boulder Canyon
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Boulder Canyon, two things run higher than the national average within ~10 miles of Boulder Canyon — Mining (54 sites) and Superfund (4 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.
Superfund: Superfund sites represent the most severe contamination in the federal system.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Commission professional soil testing before any food production (test for heavy metals, VOCs, and SVOCs).
Check your specific parcel in Boulder Canyon
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 Boulder Canyon average
Your land is one point inside Boulder Canyon
Everything above resolves to Boulder Canyon 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 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 Boulder Canyon Average
Boulder Canyon Average
- ●USDA Zones 5b, averaged across Boulder Canyon
- ●One soil character for all of Boulder Canyon
- ●Frost dates read at Boulder Canyon's scale: May 7 to Oct 7
YOUR Parcel
- ✓Your exact zone, not Boulder Canyon's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Boulder Canyon
Pull a site-specific report for your exact address in Boulder Canyon, South Dakota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Boulder Canyon averages can't show:
We read public map data around Boulder Canyon — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Boulder Canyon average
How we know this about Boulder Canyon
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 Boulder Canyon’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 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 Boulder Canyon
When does frost risk typically end in Boulder Canyon?
The last hard freeze (28°F) in Boulder Canyon typically lands around May 7, 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 28.
When is the first frost in Boulder Canyon?
The first hard freeze (28°F) in Boulder Canyon typically arrives around Oct 7, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 23, so the watching starts about Sep 7 — about 153 days after the spring freeze cleared.
How long is the growing season in Boulder Canyon?
Measured between 28°F hard freezes, Boulder Canyon sees about 153 frost-free days — roughly May 7 through Oct 7, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 28 to Sep 23, about 118 days.
Is the soil safe to grow vegetables in Boulder Canyon?
The federal record around Boulder Canyon runs heavier than most — 230 documented sites, mostly Underground Storage Tanks entries (76), the nearest Nitrate record about 1.2 miles 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 I protect my plants from frost in Boulder Canyon?
From about Sep 7 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 Oct 7 (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 Oct 7. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Boulder Canyon's scale — its 5b band and its 153-day season. Your yard writes its own version of Boulder Canyon'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 Boulder Canyon’s own scale
6 of the readings below were taken at Boulder Canyon's own scale — its own ~153-day season between 28°F freezes, the 1,958 acres it covers and 230 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Boulder Canyon's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Boulder Canyon's own 28°F hard-freeze dates, about May 7 and Oct 7 and the ~153-day span between themNOAA 1991–2020 Climate Normals
- 230 documented contamination sites on the federal record near Boulder Canyon, the closest Nitrate record about 1.2 miles out from the town centreFederal environmental registers
- Boulder Canyon's boundary and the 1,958 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~153-day seasonGrowable Ground crop-matching engine
- The ecoregion at Boulder Canyon's own centroid, the Middle RockiesUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Boulder Canyon's 1,958 acres read through its county's SSURGO summaryfrom Lawrence County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Lawrence County
- The growing challenges every South Dakota grower plans around — written at state scale, so they stay on the state guidefrom South Dakota
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Lawrence County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Boulder Canyon's 1,958 acreswhy one lot differs from the next →
- Which side of Boulder Canyon you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,958 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 1.2 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 Boulder Canyon-wide figureread your own land →
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