Edmunds County, in South Dakota, sits in USDA hardiness zone 4b — room for a real mix of vegetables, fruit, and perennials matched to the local frost calendar.
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.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Edmunds County holds more than one microclimate.
Soils and elevations shift across Edmunds County, so your frost dates and drainage aren't the county average. 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 Edmunds County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Edmunds County — the short answer
Edmunds County, South Dakota: USDA zone 4b, about 164 days between hard freezes, across 721K acres.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 28
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 9
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~164
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 721K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are county 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 Edmunds County's average, not your lot's — a low corner or a tree line moves it. Against Edmunds County's 164-day season, see what your own ground reads.
Heat in Edmunds County
Across a year, Edmunds County accumulates about 2,181 growing degree days above 50°F, about 245 fewer than the middle South Dakota county — ahead of 9 of South Dakota’s 66 counties. Degree days are the heat a crop actually gets to work with — more of them is more room to ripen a long-season crop before the freeze closes the window.
Grounded in PRISM Climate Group, Oregon State University — 1991–2020 monthly normals
Soil in Edmunds County
Across Edmunds County, the ground is predominantly Mollisols, where Williams, Bowbells, and Bryant are the most extensive named soil series. The soil is generally well drained with a loam surface. Topsoil pH runs about 6.7–7.2, neutral. Rainfall drains through hydrologic group B soils.
Soil order
Mollisols
Drainage
Well drained
Prime farmland
1%
Hydric soils
18%
Soil still varies lot by lot — soil types explained.
How the ground varies across Edmunds County
The USDA soil survey maps 70% of Edmunds County as well drained — but another 29% drains differently: 13% moderately well drained, 7% poorly drained.
Williams is the most extensive named soil at 30% of mapped acres, then Bowbells (18%) and Bryant (9%).
Which of them your own lot sits on is a parcel question, not a county one. Check your address for the survey at your boundary.
What this means for growing in Edmunds County
Each reading below is measured for Edmunds County itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Drainage
MeasuredThe dominant soils across Edmunds County are well drained, in hydrologic group B — ground that drains quickly.
The upside is soil you can work early in spring and roots that never drown; the cost is that fast-draining ground dries out fast and leaches nutrients away before plants can use them.
Work in compost and mulch to hold moisture and feed, and water more often in short doses than deep and rarely.
USDA NRCS SSURGO
Surface pH
MeasuredTopsoil across Edmunds County runs about pH 6.7–7.2, close to neutral.
This is the range most vegetables prefer — one correction you probably do not have to make, which is genuinely good news for a new bed.
Keep it there with compost rather than lime or sulfur, and only amend if your own soil test says otherwise.
USDA NRCS SSURGO
Wet ground
MeasuredAbout 18% of Edmunds County is mapped as hydric — wetland — soil.
If your lot falls in one of those pockets, a standard in-ground bed will fight waterlogging all season, and roots that need air will struggle.
Check how your own ground drains before you dig; raised beds or moisture-loving plantings turn a wet corner from a problem into a niche.
USDA NRCS SSURGO
Season length
MeasuredEdmunds County runs about 164 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
The kind of country Edmunds County is in
Edmunds County spans 2 EPA Level III ecoregions — Northwestern Glaciated Plains (71%) and Northern Glaciated Plains (29%). Which one your land falls in changes what grows wild there and how the ground behaves, and a county-wide answer cannot tell you which.
What Grows in Edmunds County
We scored all 1,086 plants against Edmunds County's own USDA zone 4b and its own 164-day season between hard freezes, using the same matching engine that runs a full parcel report. These cleared both. Sun, soil pH and drainage vary lot by lot — those are the parcel questions below. Each card opens that plant's South Dakota profile.
Is it too late to plant in Edmunds County?
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 31; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 28 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 9 — 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.
Documented around Edmunds County
- monarch butterfly50 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Edmunds County
USGS estimates 373,244 lb of Glyphosate on Edmunds County farmland in 2019, its largest by weight, ahead of Acetochlor (180,180 lb) and Dicamba (63,402 lb).
Farmland across the whole county, not any one lot. Check your address for the site-by-site record.
Safe to Grow Here?
What the federal record shows across Edmunds County — and how to grow with it.
We checked the federal record across Edmunds County — 114 documented sites across 4 of the 9 source types we track.
The most significant on record: 1 Toxics Release Inventory facility. Active industrial facilities reporting chemical releases to air, water, and land.
The federal record across Edmunds County is a modest one — a typical footprint for a growing area. Nothing here calls for alarm; it's worth knowing which recorded sites sit closest to where you grow, and each one on the map carries its type and location. If one turns out to be a near neighbor, a one-time soil test settles the question.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Edmunds County
Closest first, across Edmunds County. Listing isn't leaking, and distance isn't exposure.
- 123N69W29CBBDNitrate · 2.0 mi
- HEIERS BLDG SUPPLIESUnderground Storage Tanks · 5.0 mi
- 123N70W20CDCDNitrate · 5.7 mi
- ROSCOE AUTO COUnderground Storage Tanks · 6.8 mi
- 123N70W19CCCDNitrate · 6.9 mi
- AP XPRESSUnderground Storage Tanks · 6.9 mi
- SPEEDY'SUnderground Storage Tanks · 7.0 mi
- BURLINGTON NORTHERN RAILROADUnderground Storage Tanks · 7.0 mi
- ROSCOE PUBLIC SCHOOLUnderground Storage Tanks · 7.0 mi
- GEROLD BECKUnderground Storage Tanks · 7.0 mi
- 123N71W24DDDB (2)Nitrate · 7.0 mi
- CO HWY SHOPUnderground Storage Tanks · 7.1 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Edmunds County'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 Edmunds County.
Total Sites
114
across Edmunds County
Risk Level
Moderate
Highest-severity
1 Toxics Release Inventory facility
Sources Checked
across Edmunds County
Severity Distribution
across Edmunds County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Edmunds County, Nitrate runs higher than the national average — 82 sites across Edmunds County. 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 Edmunds County
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 Edmunds County average
Your land is one point inside Edmunds County
Everything above resolves to Edmunds County as a whole — one PHZM band and one county frost record, read across 721K 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 county 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 county average.
Your Lot vs the Edmunds County Average
Edmunds County Average
- ●USDA Zones 4b, averaged across Edmunds County
- ●One soil character for all of Edmunds County
- ●Frost dates read at Edmunds County's scale: Apr 28 to Oct 9
YOUR Parcel
- ✓Your exact zone, not Edmunds County's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Edmunds County
Pull a site-specific report for your exact address in Edmunds County, South Dakota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Edmunds County averages can't show:
We read public map data around Edmunds County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Edmunds County average
How we know this about Edmunds County
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at county grain; hard-freeze dates from NOAA 1991–2020 28°F normals at this county’s own record where one resolves, and the labelled statewide window where none does; soils from the USDA NRCS SSURGO survey, area-weighted across the county’s own map units; boundaries and acreage from US Census TIGER/Line 2025; the contamination and pesticide records from the federal sources named in their beats above. Where Edmunds County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Edmunds County
When does frost risk typically end in Edmunds County?
The last hard freeze (28°F) in Edmunds County typically lands around Apr 28, 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 19.
How long is the growing season in Edmunds County?
Measured between 28°F hard freezes, Edmunds County sees about 164 frost-free days — roughly Apr 28 through Oct 9, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 19 to Sep 25, about 129 days.
Is the soil safe to grow vegetables in Edmunds County?
The federal record around Edmunds County shows 114 documented sites, mostly Nitrate entries (82), the nearest Nitrate record about 2.0 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.
Everything above is measured at Edmunds County's scale — its 4b band and its 164-day season. Your yard writes its own version of Edmunds County's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
Will It Grow Here?
Zone fit is the first question — each answer below reads South Dakota's frost window, season length, and soil profile against the plant's real requirements.
What this page reads at Edmunds County’s own scale
9 of the readings below were taken at Edmunds County's own scale — its own ~164-day span between 28°F freezes, the 3 most extensive soil series mapped here and 114 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Edmunds County's own USDA hardiness band, zones 4bUSDA PHZM 2023
- Edmunds County's own 28°F hard-freeze dates and its ~164-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Edmunds CountyUSDA NRCS SSURGO
- 114 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Nitrate record about 2.0 miles outFederal environmental registers
- Edmunds County's boundary and the 720,627 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~164-day seasonGrowable Ground crop-matching engine
- The 2 ecoregions Edmunds County spans, Northwestern Glaciated Plains the largestUS EPA Level III Ecoregions
- Open occurrence records documented in Edmunds County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Edmunds County farmland, and roughly how muchUSGS NAWQA EPest county estimates
Inherited from a wider read
- The growing challenges every South Dakota grower plans around — written at state scale, so they stay on the state guidefrom South Dakota
What this page can’t tell you
- How the season shifts across Edmunds County — the ~164 days above is one reading at its centre; the 12 towns below each carry their owntowns in this county →
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Edmunds County's 720,627 acreswhy one lot differs from the next →
- Which of those 114 documented sites actually reaches your soil — that needs your address, the wind, and the groundwater directionhow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — none of it survives being averaged over Edmunds Countyread your own land →