Westwood Colony, South Dakota, sits in USDA hardiness zone 4a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Well-matched crops include cabbage, cranberry, turkish rocket, 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 Westwood 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 Westwood 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 Westwood Colony — soil, climate, flood, and parcel records. How we handle your address.
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Westwood Colony — the short answer
Westwood Colony, South Dakota: USDA zone 4a, about 170 days between hard freezes, across 645 acres of town.
- USDA zone
- 4a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 24
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 11
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~170
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 645 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 4a is Westwood Colony's average, not your lot's — a low corner or a tree line moves it. Against Westwood 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 Westwood Colony
Each reading below is measured for Westwood Colony itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredWestwood 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
MeasuredWestwood Colony sits in USDA hardiness zone 4a.
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 Westwood Colony is in
Westwood Colony sits in the Northern Glaciated Plains — EPA Level III, inside the wider Great Plains. That is read at Westwood Colony's own centroid rather than borrowed from Marshall County.
What Grows in Westwood Colony
Every plant below cleared Westwood Colony's own zone 4a and its 170-day season. Each card opens that plant's South Dakota profile. How we score.
Is it too late to plant in Westwood Colony?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Mar 27; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 24 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 11 — 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 Westwood Colony
Closest first, within ~10 miles of Westwood Colony. Listing isn't leaking, and distance isn't exposure.
- 128N58W22BBBBNitrate · 2500 ft
- 128N58W26ADDNitrate · 2.0 mi
- 128N57W19BBBBNitrate · 2.5 mi
- 128N58W19DAADNitrate · 2.6 mi
- 129-057-34DAANitrate · 3.5 mi
- 127N58W 2ADNitrate · 3.6 mi
- 127N58W 2ADA2Nitrate · 3.6 mi
- 128N58W 1AAAANitrate · 3.8 mi
- 128N57W31CCCCNitrate · 3.9 mi
- 129-057-34AAANitrate · 4.0 mi
- 128N57W20DDC2Nitrate · 4.4 mi
- 128N59W24CBBBNitrate · 4.4 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Westwood 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 Westwood Colony.
Total Sites
181
within ~10 miles of Westwood Colony
Risk Level
Moderate
Highest-severity
1 Toxics Release Inventory facility
Sources Checked
within ~10 miles of Westwood Colony
Severity Distribution
within ~10 miles of Westwood Colony
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Westwood Colony, Nitrate runs higher than the national average — 158 sites within ~10 miles of Westwood Colony. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around 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 Westwood 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 Westwood Colony average
Your land is one point inside Westwood Colony
Everything above resolves to Westwood Colony as a whole — one PHZM band and one 28°F frost record, read across 645 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 Westwood Colony Average
Westwood Colony Average
- ●USDA Zones 4a, averaged across Westwood Colony
- ●One soil character for all of Westwood Colony
- ●Frost dates read at Westwood Colony's scale: Apr 24 to Oct 11
YOUR Parcel
- ✓Your exact zone, not Westwood Colony's 4a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Westwood Colony
Pull a site-specific report for your exact address in Westwood Colony, South Dakota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Westwood Colony averages can't show:
We read public map data around Westwood Colony — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Westwood Colony average
How we know this about Westwood 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 Westwood 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 Westwood Colony
When does frost risk typically end in Westwood Colony?
The last hard freeze (28°F) in Westwood Colony typically lands around Apr 24, 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 15.
When is the first frost in Westwood Colony?
The first hard freeze (28°F) in Westwood Colony typically arrives around Oct 11, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 27, so the watching starts about Sep 11 — about 170 days after the spring freeze cleared.
How long is the growing season in Westwood Colony?
Measured between 28°F hard freezes, Westwood Colony sees about 170 frost-free days — roughly Apr 24 through Oct 11, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 15 to Sep 27, about 135 days.
Is the soil safe to grow vegetables in Westwood Colony?
The federal record around Westwood Colony shows 181 documented sites, mostly Nitrate entries (158), the nearest Nitrate record about 0.5 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 Westwood Colony?
From about Sep 11 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 11 (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 11. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Westwood Colony's scale — its 4a band and its 170-day season. Your yard writes its own version of Westwood 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 Westwood Colony’s own scale
6 of the readings below were taken at Westwood Colony's own scale — its own ~170-day season between 28°F freezes, the 645 acres it covers and 181 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Westwood Colony's own USDA hardiness band, zones 4aUSDA PHZM 2023
- Westwood Colony's own 28°F hard-freeze dates, about Apr 24 and Oct 11 and the ~170-day span between themNOAA 1991–2020 Climate Normals
- 181 documented contamination sites on the federal record near Westwood Colony, the closest Nitrate record about 0.5 miles out from the town centreFederal environmental registers
- Westwood Colony's boundary and the 645 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4a and a ~170-day seasonGrowable Ground crop-matching engine
- The ecoregion at Westwood 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 Westwood Colony's 645 acres read through its county's SSURGO summaryfrom Marshall County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Marshall 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 Marshall County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Westwood Colony's 645 acreswhy one lot differs from the next →
- Which side of Westwood 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 645 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 0.5 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 Westwood Colony-wide figureread your own land →