Millbrook Colony, South Dakota, sits in USDA hardiness zone 5a — a zone band wide enough that plant choice, not possibility, is the interesting question.
On paper, cabbage, cranberry, lavender, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Millbrook 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 Millbrook 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 Millbrook Colony — soil, climate, flood, and parcel records. How we handle your address.
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Millbrook Colony — the short answer
Millbrook Colony, South Dakota: USDA zone 5a, about 180 days between hard freezes, across 150 acres of town.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 20
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 17
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~180
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 150 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 5a is Millbrook Colony's average, not your lot's — a low corner or a tree line moves it. Against Millbrook Colony's 180-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Millbrook Colony
Each reading below is measured for Millbrook Colony itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredMillbrook Colony runs about 180 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
MeasuredMillbrook Colony sits in USDA hardiness zone 5a.
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 Millbrook Colony is in
Millbrook Colony sits in the Northern Glaciated Plains — EPA Level III, inside the wider Great Plains. That is read at Millbrook Colony's own centroid rather than borrowed from Hanson County.
What Grows in Millbrook Colony
Every plant below cleared Millbrook Colony's own zone 5a and its 180-day season. Each card opens that plant's South Dakota profile. How we score.
Is it too late to plant in Millbrook Colony?
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 Mar 23; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 20 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 17 — long-season crops need about 90 days of runway, quick greens only 30. Late in the year the fall bench takes over — quick greens, radishes, and garlic that repays you next summer.
What's on the federal record near Millbrook Colony
Closest first, within ~10 miles of Millbrook Colony. Listing isn't leaking, and distance isn't exposure.
- NUSTAR LOGISTICS, L.P. - MITCHELL REFINED PRODUCTS TERMINALBrownfields · 3.7 mi
- MITCHELL COMMERCIAL ASPHALTUnderground Storage Tanks · 3.9 mi
- WESTOWN TEXACOUnderground Storage Tanks · 4.2 mi
- HANSON SCHOOL DISTUnderground Storage Tanks · 4.4 mi
- HANSON SCHOOLBrownfields · 4.4 mi
- HANSON CO HWY DEPTUnderground Storage Tanks · 4.5 mi
- HEART T STOPUnderground Storage Tanks · 4.5 mi
- FARMERS ALLIANCE & UNITED ENERGYUnderground Storage Tanks · 4.5 mi
- GET N GO #3Underground Storage Tanks · 4.5 mi
- KIPS DRIVE INNUnderground Storage Tanks · 4.5 mi
- 102N58W10BCAD2Nitrate · 4.6 mi
- 102N58W10BCADNitrate · 4.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Millbrook 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 Millbrook Colony.
Total Sites
158
within ~10 miles of Millbrook Colony
Risk Level
Moderate
Highest-severity
9 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Millbrook Colony
Severity Distribution
within ~10 miles of Millbrook Colony
Highest-Severity Sites
Know Before You Grow
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •Near a brownfield, raised beds of imported soil give your food clean ground.
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
Check your specific parcel in Millbrook 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 Millbrook Colony average
Your land is one point inside Millbrook Colony
Everything above resolves to Millbrook Colony as a whole — one PHZM band and one 28°F frost record, read across 150 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 Millbrook Colony Average
Millbrook Colony Average
- ●USDA Zones 5a, averaged across Millbrook Colony
- ●One soil character for all of Millbrook Colony
- ●Frost dates read at Millbrook Colony's scale: Apr 20 to Oct 17
YOUR Parcel
- ✓Your exact zone, not Millbrook Colony's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Millbrook Colony
Pull a site-specific report for your exact address in Millbrook Colony, South Dakota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Millbrook Colony averages can't show:
We read public map data around Millbrook Colony — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Millbrook Colony average
How we know this about Millbrook 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 Millbrook 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 Millbrook Colony
When does frost risk typically end in Millbrook Colony?
The last hard freeze (28°F) in Millbrook Colony typically lands around Apr 20, 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 11.
When is the first frost in Millbrook Colony?
The first hard freeze (28°F) in Millbrook Colony typically arrives around Oct 17, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 3, so the watching starts about Sep 17 — about 180 days after the spring freeze cleared.
How long is the growing season in Millbrook Colony?
Measured between 28°F hard freezes, Millbrook Colony sees about 180 frost-free days — roughly Apr 20 through Oct 17, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 11 to Oct 3, about 145 days.
Is the soil safe to grow vegetables in Millbrook Colony?
The federal record around Millbrook Colony shows 158 documented sites, mostly Underground Storage Tanks entries (76), the nearest Brownfields record about 3.7 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 Millbrook Colony?
From about Sep 17 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 17 (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 17. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Millbrook Colony's scale — its 5a band and its 180-day season. Your yard writes its own version of Millbrook 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 Millbrook Colony’s own scale
6 of the readings below were taken at Millbrook Colony's own scale — its own ~180-day season between 28°F freezes, the 150 acres it covers and 158 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Millbrook Colony's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Millbrook Colony's own 28°F hard-freeze dates, about Apr 20 and Oct 17 and the ~180-day span between themNOAA 1991–2020 Climate Normals
- 158 documented contamination sites on the federal record near Millbrook Colony, the closest Brownfields record about 3.7 miles out from the town centreFederal environmental registers
- Millbrook Colony's boundary and the 150 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~180-day seasonGrowable Ground crop-matching engine
- The ecoregion at Millbrook Colony's own centroid, the Northern Glaciated PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Millbrook Colony's 150 acres read through its county's SSURGO summaryfrom Hanson County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Hanson 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 Hanson County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Millbrook Colony's 150 acreswhy one lot differs from the next →
- Which side of Millbrook 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 150 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields record about 3.7 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 Millbrook Colony-wide figureread your own land →
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