Delmont, South Dakota, sits in USDA hardiness zone 5a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
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 Delmont, 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 Delmont 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 Delmont — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Delmont — the short answer
Delmont, South Dakota: USDA zone 5a, about 182 days between hard freezes, across 488 acres of city.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 19
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 18
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~182
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 488 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 Delmont's average, not your lot's — a low corner or a tree line moves it. Against Delmont's 182-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Delmont
Each reading below is measured for Delmont itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredDelmont runs about 182 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
MeasuredDelmont 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 Delmont is in
Delmont sits in the Northwestern Glaciated Plains — EPA Level III, inside the wider Great Plains. That is read at Delmont's own centroid rather than borrowed from Douglas County.
What Grows in Delmont
Every plant below cleared Delmont's own zone 5a and its 182-day season. Each card opens that plant's South Dakota profile. How we score.
Is it too late to plant in Delmont?
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 22; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 19 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 18 — 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 Delmont
Closest first, within ~10 miles of Delmont. Listing isn't leaking, and distance isn't exposure.
- TERRYS REPAIR SERVICEUnderground Storage Tanks · 650 ft
- CITY OF DELMONTUnderground Storage Tanks · 1000 ft
- DOUGLAS CO HWY DEPT SHOP #4Underground Storage Tanks · 1100 ft
- AGLAND COOPUnderground Storage Tanks · 1300 ft
- 98N62W34BBADNitrate · 1400 ft
- 98N62W34BBABNitrate · 1600 ft
- 98N62W34BCBDNitrate · 2300 ft
- DOZYS OILUnderground Storage Tanks · 2300 ft
- GROSZ DRILLING CO.Underground Storage Tanks · 2500 ft
- 98N62W27ABBBNitrate · 1.3 mi
- VERN GOEHRINGUnderground Storage Tanks · 1.8 mi
- 98N62W24BBCC2Nitrate · 2.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Delmont'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 Delmont.
Sources Checked
within ~10 miles of Delmont
Severity Distribution
within ~10 miles of Delmont
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Delmont, Nitrate runs higher than the national average — 100 sites within ~10 miles of Delmont. 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 Delmont
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 Delmont average
Your land is one point inside Delmont
Everything above resolves to Delmont as a whole — one PHZM band and one 28°F frost record, read across 488 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 Delmont Average
Delmont Average
- ●USDA Zones 5a, averaged across Delmont
- ●One soil character for all of Delmont
- ●Frost dates read at Delmont's scale: Apr 19 to Oct 18
YOUR Parcel
- ✓Your exact zone, not Delmont's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Delmont
Pull a site-specific report for your exact address in Delmont, South Dakota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Delmont averages can't show:
We read public map data around Delmont — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Delmont average
How we know this about Delmont
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 Delmont’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 Delmont
When does frost risk typically end in Delmont?
The last hard freeze (28°F) in Delmont typically lands around Apr 19, 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 10.
When is the first frost in Delmont?
The first hard freeze (28°F) in Delmont typically arrives around Oct 18, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 4, so the watching starts about Sep 18 — about 182 days after the spring freeze cleared.
How long is the growing season in Delmont?
Measured between 28°F hard freezes, Delmont sees about 182 frost-free days — roughly Apr 19 through Oct 18, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 10 to Oct 4, about 147 days.
Is the soil safe to grow vegetables in Delmont?
The federal record around Delmont shows 114 documented sites, mostly Nitrate entries (100), the nearest Underground Storage Tanks record about 0.1 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 Delmont?
From about Sep 18 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 18 (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 18. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Delmont's scale — its 5a band and its 182-day season. Your yard writes its own version of Delmont'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 Delmont’s own scale
6 of the readings below were taken at Delmont's own scale — its own ~182-day season between 28°F freezes, the 488 acres it covers and 114 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Delmont's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Delmont's own 28°F hard-freeze dates, about Apr 19 and Oct 18 and the ~182-day span between themNOAA 1991–2020 Climate Normals
- 114 documented contamination sites on the federal record near Delmont, the closest Underground Storage Tanks record about 0.1 miles out from the town centreFederal environmental registers
- Delmont's boundary and the 488 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~182-day seasonGrowable Ground crop-matching engine
- The ecoregion at Delmont's own centroid, the Northwestern Glaciated PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Delmont's 488 acres read through its county's SSURGO summaryfrom Douglas County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Douglas 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 Douglas County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Delmont's 488 acreswhy one lot differs from the next →
- Which side of Delmont you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 488 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.1 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 Delmont-wide figureread your own land →
More in South Dakota
Wider growing context
What grows across South DakotaDelmont sits outside our named growing regions, so South Dakota as a whole is its closest context here.
Nearby growing guides