Lake 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.
The conditions favor cabbage, cranberry, turkish rocket, and collard greens, among others — though every individual site edits that list with its own soil, sun, and drainage.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Lake County holds more than one microclimate.
Soils and elevations shift across Lake 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 Lake County — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Lake County — the short answer
Lake County, South Dakota: USDA zone 4b, about 170 days between hard freezes, across 360K acres.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 23
- NOAA 1991–2020 Climate Normals, 28°F
- First hard freeze (28°F)
- Oct 10
- NOAA 1991–2020 Climate Normals, 28°F
- Days between freezes
- ~170
- NOAA 1991–2020 Climate Normals, 28°F
- County area
- 360K 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 Lake County's average, not your lot's — a low corner or a tree line moves it. Against Lake County's 170-day season, see what your own ground reads.
Heat in Lake County
Across a year, Lake County accumulates about 2,318 growing degree days above 50°F, about 108 fewer than the middle South Dakota county — ahead of 22 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 Lake County
Across Lake County, the ground is predominantly Mollisols, where Egan, Viborg, and Wentworth are the most extensive named soil series. The soil is generally well drained with a silty clay loam surface. Topsoil pH runs about 6.5–6.7, neutral. Rainfall drains through hydrologic group C soils.
Soil order
Mollisols
Drainage
Well drained
Prime farmland
58%
Hydric soils
18%
Soil still varies lot by lot — soil types explained.
How the ground varies across Lake County
The USDA soil survey maps 64% of Lake County as well drained — but another 33% drains differently: 10% moderately well drained, 9% very poorly drained.
Egan is the most extensive named soil at 28% of mapped acres, then Viborg (10%) and Wentworth (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 Lake County
Each reading below is measured for Lake 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 Lake County are well drained, in hydrologic group C — 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 Lake County runs about pH 6.5–6.7, 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 Lake 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
MeasuredLake County 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
The kind of country Lake County is in
Lake County sits in the Northern Glaciated Plains — EPA Level III, inside the wider Great Plains. One consistent ecological setting across the whole county.
What Grows in Lake County
We scored all 1,086 plants against Lake County's own USDA zone 4b and its own 170-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 Lake County?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Mar 26; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 23 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 10 — 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.
Documented around Lake County
- monarch butterfly88 documented records
Sighting records, so they follow observers as much as insects.
What gets applied to farmland in Lake County
USGS estimates 112,878 lb of Glyphosate on Lake County farmland in 2019, its largest by weight, ahead of Acetochlor (69,512 lb) and Atrazine (33,448 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 Lake County — and how to grow with it.
We checked the federal record across Lake County — 164 documented sites across 6 of the 9 source types we track.
The most significant on record: 1 Superfund site (none NPL-listed). Sites tracked in EPA's Superfund program — from assessment-stage CERCLIS entries to confirmed National Priorities List cleanup sites.
There's a meaningful federal record across Lake County — worth a look before you plant food, not a reason to hold back from growing. Proximity to a documented site is information, not a diagnosis of any one yard. A soil test before new food beds is the sensible precaution here, and the map shows exactly which sites sit where, so you can see what's actually near you.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
What's on the federal record near Lake County
Closest first, across Lake County. Listing isn't leaking, and distance isn't exposure.
- PROSTROLLO MOTOR CO.Brownfields · 1.1 mi
- MADISON COMMUNITY HOSPITALUnderground Storage Tanks · 1.2 mi
- DAKOTA STATE UNIVERSITYUnderground Storage Tanks · 1.2 mi
- DSU PHYSICAL PLANTUnderground Storage Tanks · 1.2 mi
- LAKE CENTRAL SCHOOL DIST 39-2Underground Storage Tanks · 1.2 mi
- DAKOTA STATE UNIVERSITYBrownfields · 1.3 mi
- MADISON CENTRAL SCHOOL DISTRICT #39-2Brownfields · 1.3 mi
- SIEDSEHLAW IMPL INCUnderground Storage Tanks · 1.5 mi
- GOLDIE KELLOGGUnderground Storage Tanks · 1.5 mi
- J & L ENTERPRISESUnderground Storage Tanks · 1.5 mi
- HOLIDAY STATION STORE #187Underground Storage Tanks · 1.5 mi
- HOLIDAY STORE - MADISONBrownfields · 1.5 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Lake 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 Lake County.
Total Sites
164
across Lake County
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
across Lake County
Severity Distribution
across Lake County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Lake County, Nitrate runs higher than the national average — 80 sites across Lake County. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
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 Lake 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 Lake County average
Your land is one point inside Lake County
Everything above resolves to Lake County as a whole — one PHZM band and one county frost record, read across 360K 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 Lake County Average
Lake County Average
- ●USDA Zones 4b, averaged across Lake County
- ●One soil character for all of Lake County
- ●Frost dates read at Lake County's scale: Apr 23 to Oct 10
YOUR Parcel
- ✓Your exact zone, not Lake County's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Lake County
Pull a site-specific report for your exact address in Lake County, South Dakota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Lake County averages can't show:
We read public map data around Lake County — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Lake County average
How we know this about Lake 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 Lake County carries no record of its own, the figure is inherited and labelled — the resolution ledger below names each.
Common questions about Lake County
When does frost risk typically end in Lake County?
The last hard freeze (28°F) in Lake County typically lands around Apr 23, 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 14.
How long is the growing season in Lake County?
Measured between 28°F hard freezes, Lake County sees about 170 frost-free days — roughly Apr 23 through Oct 10, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 14 to Sep 26, about 135 days.
Is the soil safe to grow vegetables in Lake County?
The federal record around Lake County is a meaningful one — 164 documented sites, mostly Nitrate entries (80), the nearest Brownfields record about 1.1 miles out — so a soil test before new food beds is a sensible precaution here, not a reason to hold back from growing. Remember that proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what sits where.
Everything above is measured at Lake County's scale — its 4b band and its 170-day season. Your yard writes its own version of Lake 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 Lake County’s own scale
9 of the readings below were taken at Lake County's own scale — its own ~170-day span between 28°F freezes, the 3 most extensive soil series mapped here and 164 documented sites inside its boundary; one is borrowed from a wider read, named and linked below.
Measured here
- Lake County's own USDA hardiness band, zones 4bUSDA PHZM 2023
- Lake County's own 28°F hard-freeze dates and its ~170-day span between themNOAA 1991–2020 Climate Normals
- The soil order, drainage, surface pH, and the 3 most extensive named soil series mapped in Lake CountyUSDA NRCS SSURGO
- 164 documented contamination sites inside the county boundary, distance-sorted from its center — the closest Brownfields record about 1.1 miles outFederal environmental registers
- Lake County's boundary and the 360,259 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~170-day seasonGrowable Ground crop-matching engine
- Lake County sitting wholly inside the Northern Glaciated PlainsUS EPA Level III Ecoregions
- Open occurrence records documented in Lake County for a tracked speciesGBIF derived datasets (CC0 / CC BY 4.0)
- Which agricultural compounds go onto Lake 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 Lake County — the ~170 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 Lake County's 360,259 acreswhy one lot differs from the next →
- Which of those 164 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 Lake Countyread your own land →