Wilmot, South Dakota, sits in USDA hardiness zone 4b — a zone band wide enough that plant choice, not possibility, is the interesting question.
Reliable performers under these conditions include cabbage, cranberry, turkish rocket, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Even in Wilmot, 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 Wilmot 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 Wilmot — soil, climate, flood, and parcel records. How we handle your address.
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Wilmot — the short answer
Wilmot, South Dakota: USDA zone 4b, about 167 days between hard freezes, across 341 acres of city.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 27
- 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
- ~167
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 341 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 Wilmot's average, not your lot's — a low corner or a tree line moves it. Against Wilmot's 167-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Wilmot
Each reading below is measured for Wilmot itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredWilmot runs about 167 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
MeasuredWilmot 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 Wilmot is in
Wilmot sits in the Northern Glaciated Plains — EPA Level III, inside the wider Great Plains. That is read at Wilmot's own centroid rather than borrowed from Roberts County.
What Grows in Wilmot
Every plant below cleared Wilmot's own zone 4b and its 167-day season. Each card opens that plant's South Dakota profile. How we score.
Is it too late to plant in Wilmot?
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 30; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 27 (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. As the window narrows, the plantings just get faster — fall brassicas, then greens, then garlic to finish.
What's on the federal record near Wilmot
Closest first, within ~10 miles of Wilmot. Listing isn't leaking, and distance isn't exposure.
- 122N49W 6BCAA2Nitrate · 800 ft
- 122N49W 6BCABNitrate · 800 ft
- 122N49W 6BCAANitrate · 850 ft
- OSTERLOH OIL CO.Underground Storage Tanks · 1300 ft
- JURGENS OIL COUnderground Storage Tanks · 1700 ft
- JURGENS OIL #2Underground Storage Tanks · 1800 ft
- 122N49W 7BBBBNitrate · 0.8 mi
- GRANT-ROBERTS RURAL WATER SYSTEMPFAS · 0.8 mi
- 122N49W18AAAANitrate · 1.8 mi
- 123N50W35AAAANitrate · 1.8 mi
- 122N49W17AAADNitrate · 2.4 mi
- 123N50W25BABBNitrate · 2.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Wilmot'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 Wilmot.
Total Sites
57
within ~10 miles of Wilmot
Risk Level
Moderate
Highest-severity
2 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Wilmot
Severity Distribution
within ~10 miles of Wilmot
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Wilmot, Nitrate runs higher than the national average — 48 sites within ~10 miles of Wilmot. 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 Wilmot
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 Wilmot average
Your land is one point inside Wilmot
Everything above resolves to Wilmot as a whole — one PHZM band and one 28°F frost record, read across 341 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 Wilmot Average
Wilmot Average
- ●USDA Zones 4b, averaged across Wilmot
- ●One soil character for all of Wilmot
- ●Frost dates read at Wilmot's scale: Apr 27 to Oct 11
YOUR Parcel
- ✓Your exact zone, not Wilmot's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Wilmot
Pull a site-specific report for your exact address in Wilmot, South Dakota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Wilmot averages can't show:
We read public map data around Wilmot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Wilmot average
How we know this about Wilmot
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 Wilmot’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 Wilmot
When does frost risk typically end in Wilmot?
The last hard freeze (28°F) in Wilmot typically lands around Apr 27, 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 18.
When is the first frost in Wilmot?
The first hard freeze (28°F) in Wilmot 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 167 days after the spring freeze cleared.
How long is the growing season in Wilmot?
Measured between 28°F hard freezes, Wilmot sees about 167 frost-free days — roughly Apr 27 through Oct 11, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 18 to Sep 27, about 132 days.
Is the soil safe to grow vegetables in Wilmot?
The federal record around Wilmot shows 57 documented sites, mostly Nitrate entries (48), the nearest Nitrate record about 0.2 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 Wilmot?
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 Wilmot's scale — its 4b band and its 167-day season. Your yard writes its own version of Wilmot'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 Wilmot’s own scale
6 of the readings below were taken at Wilmot's own scale — its own ~167-day season between 28°F freezes, the 341 acres it covers and 57 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Wilmot's own USDA hardiness band, zones 4bUSDA PHZM 2023
- Wilmot's own 28°F hard-freeze dates, about Apr 27 and Oct 11 and the ~167-day span between themNOAA 1991–2020 Climate Normals
- 57 documented contamination sites on the federal record near Wilmot, the closest Nitrate record about 0.2 miles out from the town centreFederal environmental registers
- Wilmot's boundary and the 341 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~167-day seasonGrowable Ground crop-matching engine
- The ecoregion at Wilmot's own centroid, the Northern Glaciated PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Wilmot's 341 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 Wilmot's 341 acreswhy one lot differs from the next →
- Which side of Wilmot you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 341 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 0.2 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 Wilmot-wide figureread your own land →