White Rock Colony, South Dakota, sits in USDA hardiness zone 4b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
A short list that earns its place here — cabbage, cranberry, turkish rocket, and collard greens — with any one site's soil, sun, and drainage making the final cut.
Even in White Rock Colony, 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 White Rock Colony 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 White Rock Colony — soil, climate, flood, and parcel records. How we handle your address.
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White Rock Colony — the short answer
White Rock Colony, South Dakota: USDA zone 4b, about 170 days between hard freezes, across 367 acres of town.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 23
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 10
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~170
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 367 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 4b is White Rock Colony's average, not your lot's — a low corner or a tree line moves it. Against White Rock Colony's 170-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in White Rock Colony
Each reading below is measured for White Rock Colony itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredWhite Rock Colony runs about 170 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
MeasuredWhite Rock Colony sits in USDA hardiness zone 4b.
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 White Rock Colony is in
White Rock Colony sits in the Lake Agassiz Plain — EPA Level III, inside the wider Great Plains. That is read at White Rock Colony's own centroid, and it is not what its county reads: Roberts County is mostly Northern Glaciated Plains. The wider page above you is answering a different question about different ground.
What Grows in White Rock Colony
Every plant below cleared White Rock Colony's own zone 4b and its 170-day season. Each card opens that plant's South Dakota profile. How we score.
Is it too late to plant in White Rock Colony?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Mar 26; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 23 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 10 — long-season crops need about 90 days of runway, quick greens only 30. Even past midsummer there is room for a true fall garden here, and garlic planted near the close carries the momentum into next year.
What's on the federal record near White Rock Colony
Closest first, within ~10 miles of White Rock Colony. Listing isn't leaking, and distance isn't exposure.
- 128N48W 1CCDC2 RNitrate · 1.4 mi
- 129N48W33ADDA RNitrate · 1.4 mi
- 128N48W 4DDDD RNitrate · 2.0 mi
- 517045Nitrate · 3.7 mi
- 129-048-27CCCNitrate · 4.1 mi
- 129-048-24DAA1Nitrate · 4.2 mi
- 128N48W17BCCB2 RNitrate · 4.4 mi
- 128N48W18ABAD RNitrate · 4.5 mi
- 129-048-28CDDNitrate · 4.5 mi
- 128N49W 1DDAD2 RNitrate · 4.7 mi
- 128N47W02DCD 01 Rbt BruceNitrate · 4.8 mi
- 128N48W20BBBB RNitrate · 4.8 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from White Rock Colony'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 White Rock Colony.
Total Sites
96
within ~10 miles of White Rock Colony
Risk Level
Moderate
Highest-severity
1 Toxics Release Inventory facility
Sources Checked
within ~10 miles of White Rock Colony
Severity Distribution
within ~10 miles of White Rock Colony
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around White Rock Colony, Nitrate runs higher than the national average — 70 sites within ~10 miles of White Rock Colony. That's not a problem with your land — it's information about 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 White Rock Colony
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 White Rock Colony average
Your land is one point inside White Rock Colony
Everything above resolves to White Rock Colony as a whole — one PHZM band and one 28°F frost record, read across 367 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 White Rock Colony Average
White Rock Colony Average
- ●USDA Zones 4b, averaged across White Rock Colony
- ●One soil character for all of White Rock Colony
- ●Frost dates read at White Rock Colony's scale: Apr 23 to Oct 10
YOUR Parcel
- ✓Your exact zone, not White Rock Colony's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in White Rock Colony
Pull a site-specific report for your exact address in White Rock Colony, South Dakota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that White Rock Colony averages can't show:
We read public map data around White Rock Colony — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the White Rock Colony average
How we know this about White Rock Colony
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 White Rock Colony’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 White Rock Colony
When does frost risk typically end in White Rock Colony?
The last hard freeze (28°F) in White Rock Colony typically lands around Apr 23, 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 14.
When is the first frost in White Rock Colony?
The first hard freeze (28°F) in White Rock Colony typically arrives around Oct 10, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 26, so the watching starts about Sep 10 — about 170 days after the spring freeze cleared.
How long is the growing season in White Rock Colony?
Measured between 28°F hard freezes, White Rock Colony sees about 170 frost-free days — roughly Apr 23 through Oct 10, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 14 to Sep 26, about 135 days.
Is the soil safe to grow vegetables in White Rock Colony?
The federal record around White Rock Colony shows 96 documented sites, mostly Nitrate entries (70), the nearest Nitrate record about 1.4 miles out — a typical footprint for a growing area, and proximity to a documented site is information, not a diagnosis of any one yard. It's worth seeing which recorded sites sit closest to where you grow, and testing the soil before new food beds near any of them.
How do I protect my plants from frost in White Rock Colony?
From about Sep 10 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 10 (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 10. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at White Rock Colony's scale — its 4b band and its 170-day season. Your yard writes its own version of White Rock Colony'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 White Rock Colony’s own scale
6 of the readings below were taken at White Rock Colony's own scale — its own ~170-day season between 28°F freezes, the 367 acres it covers and 96 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- White Rock Colony's own USDA hardiness band, zones 4bUSDA PHZM 2023
- White Rock Colony's own 28°F hard-freeze dates, about Apr 23 and Oct 10 and the ~170-day span between themNOAA 1991–2020 Climate Normals
- 96 documented contamination sites on the federal record near White Rock Colony, the closest Nitrate record about 1.4 miles out from the town centreFederal environmental registers
- White Rock Colony's boundary and the 367 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~170-day seasonGrowable Ground crop-matching engine
- White Rock Colony sits in the Lake Agassiz Plain — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so White Rock Colony's 367 acres read through its county's SSURGO summaryfrom Roberts County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Roberts 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 Roberts County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among White Rock Colony's 367 acreswhy one lot differs from the next →
- Which side of White Rock Colony you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 367 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 1.4 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 White Rock Colony-wide figureread your own land →