Smithwick, South Dakota, sits in USDA hardiness zone 5a — 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 Smithwick, 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 Smithwick 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 Smithwick — soil, climate, flood, and parcel records. How we handle your address.
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Smithwick — the short answer
Smithwick, South Dakota: USDA zone 5a, about 159 days between hard freezes, across 1K acres of town.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 5
- 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
- ~159
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 1K 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 Smithwick's average, not your lot's — a low corner or a tree line moves it. Against Smithwick's 159-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Smithwick
Each reading below is measured for Smithwick itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredSmithwick runs about 159 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
MeasuredSmithwick 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 Smithwick is in
Smithwick sits in the Northwestern Great Plains — EPA Level III, inside the wider Great Plains. That is read at Smithwick's own centroid rather than borrowed from Fall River County.
What Grows in Smithwick
Every plant below cleared Smithwick's own zone 5a and its 159-day season. Each card opens that plant's South Dakota profile. How we score.
Is it too late to plant in Smithwick?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Apr 7; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 5 (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. 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 Smithwick
Closest first, within ~10 miles of Smithwick. Listing isn't leaking, and distance isn't exposure.
- 10S 8E 5Nitrate · 6.1 mi
- HILLS EDGE AUTO SALESUnderground Storage Tanks · 6.7 mi
- GRIN AND BEAR IT GASUnderground Storage Tanks · 6.7 mi
- FORNEYS STANDARD SERVICEUnderground Storage Tanks · 7.6 mi
- ORAL SAND PLANTUnderground Storage Tanks · 8.0 mi
- BILLS SUPER VALUEUnderground Storage Tanks · 8.2 mi
- 10S 7E13DADDNitrate · 8.3 mi
- SD DEPT OF TRANSPORTATIONUnderground Storage Tanks · 8.6 mi
- FALL RIVER FEEDLOTS INCUnderground Storage Tanks · 8.7 mi
- 008S06E14ADCDNitrate · 8.7 mi
Measured from Smithwick'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 Smithwick.
Severity Distribution
within ~10 miles of Smithwick
Highest-Severity Sites
Know Before You Grow
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
Check your specific parcel in Smithwick
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 Smithwick average
Your land is one point inside Smithwick
Everything above resolves to Smithwick as a whole — one PHZM band and one 28°F frost record, read across 1K 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 Smithwick Average
Smithwick Average
- ●USDA Zones 5a, averaged across Smithwick
- ●One soil character for all of Smithwick
- ●Frost dates read at Smithwick's scale: May 5 to Oct 11
YOUR Parcel
- ✓Your exact zone, not Smithwick's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Smithwick
Pull a site-specific report for your exact address in Smithwick, South Dakota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Smithwick averages can't show:
We read public map data around Smithwick — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Smithwick average
How we know this about Smithwick
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 Smithwick’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 Smithwick
When does frost risk typically end in Smithwick?
The last hard freeze (28°F) in Smithwick typically lands around May 5, 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 26.
When is the first frost in Smithwick?
The first hard freeze (28°F) in Smithwick 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 159 days after the spring freeze cleared.
How long is the growing season in Smithwick?
Measured between 28°F hard freezes, Smithwick sees about 159 frost-free days — roughly May 5 through Oct 11, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 26 to Sep 27, about 124 days.
Is the soil safe to grow vegetables in Smithwick?
The federal record around Smithwick is light — 13 documented sites across the 9 federal source types we checked, mostly Underground Storage Tanks entries (7), the nearest Nitrate record about 6.1 miles out — and proximity to a documented site is information, not a diagnosis of any one yard. Growing food here starts from a strong position; a soil test before new food beds settles any site-specific question.
How do I protect my plants from frost in Smithwick?
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 Smithwick's scale — its 5a band and its 159-day season. Your yard writes its own version of Smithwick'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 Smithwick’s own scale
6 of the readings below were taken at Smithwick's own scale — its own ~159-day season between 28°F freezes, the 1,237 acres it covers and 13 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Smithwick's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Smithwick's own 28°F hard-freeze dates, about May 5 and Oct 11 and the ~159-day span between themNOAA 1991–2020 Climate Normals
- 13 documented contamination sites on the federal record near Smithwick, the closest Nitrate record about 6.1 miles out from the town centreFederal environmental registers
- Smithwick's boundary and the 1,237 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~159-day seasonGrowable Ground crop-matching engine
- The ecoregion at Smithwick's own centroid, the Northwestern Great PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Smithwick's 1,237 acres read through its county's SSURGO summaryfrom Fall River County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Fall River 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 Fall River County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Smithwick's 1,237 acreswhy one lot differs from the next →
- Which side of Smithwick you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,237 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 6.1 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 Smithwick-wide figureread your own land →
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