Glenham, South Dakota, sits in USDA hardiness zone 4b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
A short list that earns its place here — cabbage, cranberry, turkish rocket, and collard greens — with any one site's soil, sun, and drainage making the final cut.
Even in Glenham, 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 Glenham 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 Glenham — soil, climate, flood, and parcel records. How we handle your address.
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Glenham — the short answer
Glenham, South Dakota: USDA zone 4b, about 168 days between hard freezes, across 209 acres of town.
- 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 12
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~168
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 209 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 Glenham's average, not your lot's — a low corner or a tree line moves it. Against Glenham's 168-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Glenham
Each reading below is measured for Glenham itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredGlenham runs about 168 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
MeasuredGlenham 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 Glenham is in
Glenham sits in the Northwestern Glaciated Plains — EPA Level III, inside the wider Great Plains. That is read at Glenham's own centroid rather than borrowed from Walworth County.
What Grows in Glenham
Every plant below cleared Glenham's own zone 4b and its 168-day season. Each card opens that plant's South Dakota profile. How we score.
Is it too late to plant in Glenham?
Usually not — gardeners here simply switch what goes in the ground as the season moves. 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 12 — 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 Glenham
Closest first, within ~10 miles of Glenham. Listing isn't leaking, and distance isn't exposure.
- 124N78W28ACBANitrate · 300 ft
- 124N78W28ABBANitrate · 1200 ft
- 124N78W23BBBBNitrate · 1.8 mi
- 123N78W 3BABANitrate · 1.9 mi
- 124N78W19AADA (2)Nitrate · 2.0 mi
- WALWORTH COUNTY LANDFILLToxics Release Inventory · 3.2 mi
- 123N78W12BDCCNitrate · 4.2 mi
- 125N78W33DDDNitrate · 4.4 mi
- 125N78W32BCBNitrate · 5.4 mi
- AKASKA EQUITY EXCHANGEUnderground Storage Tanks · 5.4 mi
- BRIDGE CITY MARINA INC.Underground Storage Tanks · 5.7 mi
- MOBRIDGE SUB-OFFICEUnderground Storage Tanks · 5.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Glenham'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 Glenham.
Total Sites
85
within ~10 miles of Glenham
Risk Level
Moderate
Highest-severity
1 Toxics Release Inventory facility
Sources Checked
within ~10 miles of Glenham
Severity Distribution
within ~10 miles of Glenham
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Glenham, Nitrate runs higher than the national average — 52 sites within ~10 miles of Glenham. 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 Glenham
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 Glenham average
Your land is one point inside Glenham
Everything above resolves to Glenham as a whole — one PHZM band and one 28°F frost record, read across 209 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 Glenham Average
Glenham Average
- ●USDA Zones 4b, averaged across Glenham
- ●One soil character for all of Glenham
- ●Frost dates read at Glenham's scale: Apr 27 to Oct 12
YOUR Parcel
- ✓Your exact zone, not Glenham's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Glenham
Pull a site-specific report for your exact address in Glenham, South Dakota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Glenham averages can't show:
We read public map data around Glenham — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Glenham average
How we know this about Glenham
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 Glenham’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 Glenham
When does frost risk typically end in Glenham?
The last hard freeze (28°F) in Glenham 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 Glenham?
The first hard freeze (28°F) in Glenham typically arrives around Oct 12, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 28, so the watching starts about Sep 12 — about 168 days after the spring freeze cleared.
How long is the growing season in Glenham?
Measured between 28°F hard freezes, Glenham sees about 168 frost-free days — roughly Apr 27 through Oct 12, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 18 to Sep 28, about 133 days.
Is the soil safe to grow vegetables in Glenham?
The federal record around Glenham shows 85 documented sites, mostly Nitrate entries (52), the nearest Nitrate record under a tenth of a mile 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 Glenham?
From about Sep 12 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 12 (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 12. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Glenham's scale — its 4b band and its 168-day season. Your yard writes its own version of Glenham'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 Glenham’s own scale
6 of the readings below were taken at Glenham's own scale — its own ~168-day season between 28°F freezes, the 209 acres it covers and 85 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Glenham's own USDA hardiness band, zones 4bUSDA PHZM 2023
- Glenham's own 28°F hard-freeze dates, about Apr 27 and Oct 12 and the ~168-day span between themNOAA 1991–2020 Climate Normals
- 85 documented contamination sites on the federal record near Glenham, the closest Nitrate record under a tenth of a mile out from the town centreFederal environmental registers
- Glenham's boundary and the 209 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~168-day seasonGrowable Ground crop-matching engine
- The ecoregion at Glenham's own centroid, the Northwestern Glaciated PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Glenham's 209 acres read through its county's SSURGO summaryfrom Walworth County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Walworth 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 Walworth County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Glenham's 209 acreswhy one lot differs from the next →
- Which side of Glenham you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 209 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record under a tenth of a mile 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 Glenham-wide figureread your own land →
More in South Dakota
Wider growing context
What grows across South DakotaGlenham sits outside our named growing regions, so South Dakota as a whole is its closest context here.
Nearby growing guides