Mandan, North Dakota, sits in USDA hardiness zone 4a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
On paper, cabbage, cranberry, turkish rocket, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Mandan, 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 Mandan 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 Mandan — soil, climate, flood, and parcel records. How we handle your address.
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Mandan — the short answer
Mandan, North Dakota: USDA zone 4a, about 158 days between hard freezes, across 9K acres of city.
- USDA zone
- 4a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 2
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 7
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~158
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 9K 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 4a is Mandan's average, not your lot's — a low corner or a tree line moves it. Against Mandan's 158-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Mandan
Each reading below is measured for Mandan itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredMandan runs about 158 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
MeasuredMandan sits in USDA hardiness zone 4a.
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 Mandan is in
Mandan sits in the Northwestern Great Plains — EPA Level III, inside the wider Great Plains. That is read at Mandan's own centroid rather than borrowed from Morton County.
What Grows in Mandan
Every plant below cleared Mandan's own zone 4a and its 158-day season. Each card opens that plant's North Dakota profile. How we score.
Is it too late to plant in Mandan?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Apr 4; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 2 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 7 — 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 Mandan
Closest first, within ~10 miles of Mandan. Listing isn't leaking, and distance isn't exposure.
- M and H GasUnderground Storage Tanks · 900 ft
- Champion Auto StoresUnderground Storage Tanks · 900 ft
- O'REILLY AUTO PARTS STORE 2022Brownfields · 1000 ft
- Speedys Tire Service IncUnderground Storage Tanks · 1000 ft
- Mandan TransferUnderground Storage Tanks · 1100 ft
- Mandan Fire DepartmentUnderground Storage Tanks · 1200 ft
- Zora IncUnderground Storage Tanks · 1300 ft
- Morton CountyUnderground Storage Tanks · 1400 ft
- General StoreUnderground Storage Tanks · 1600 ft
- Farmers Union Oil CompanyUnderground Storage Tanks · 1700 ft
- Mandan Supply and Equipment IncUnderground Storage Tanks · 1800 ft
- Stop and ShopUnderground Storage Tanks · 2000 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Mandan'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 Mandan.
Total Sites
615
within ~10 miles of Mandan
Risk Level
Elevated
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Mandan
Severity Distribution
within ~10 miles of Mandan
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Mandan, Nitrate runs higher than the national average — 200 sites within ~10 miles of Mandan. That's not a problem with your land — it's information about 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 Mandan
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 Mandan average
Your land is one point inside Mandan
Everything above resolves to Mandan as a whole — one PHZM band and one 28°F frost record, read across 9K 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 Mandan Average
Mandan Average
- ●USDA Zones 4a, averaged across Mandan
- ●One soil character for all of Mandan
- ●Frost dates read at Mandan's scale: May 2 to Oct 7
YOUR Parcel
- ✓Your exact zone, not Mandan's 4a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Mandan
Pull a site-specific report for your exact address in Mandan, North Dakota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Mandan averages can't show:
We read public map data around Mandan — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Mandan average
How we know this about Mandan
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 Mandan’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 Mandan
When does frost risk typically end in Mandan?
The last hard freeze (28°F) in Mandan typically lands around May 2, 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 23.
When is the first frost in Mandan?
The first hard freeze (28°F) in Mandan typically arrives around Oct 7, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 23, so the watching starts about Sep 7 — about 158 days after the spring freeze cleared.
How long is the growing season in Mandan?
Measured between 28°F hard freezes, Mandan sees about 158 frost-free days — roughly May 2 through Oct 7, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 23 to Sep 23, about 123 days.
Is the soil safe to grow vegetables in Mandan?
The federal record around Mandan is a meaningful one — 615 documented sites, mostly Underground Storage Tanks entries (262), the nearest Underground Storage Tanks record about 0.2 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.
How do I protect my plants from frost in Mandan?
From about Sep 7 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 7 (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 7. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Mandan's scale — its 4a band and its 158-day season. Your yard writes its own version of Mandan'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 Mandan’s own scale
6 of the readings below were taken at Mandan's own scale — its own ~158-day season between 28°F freezes, the 8,651 acres it covers and 615 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Mandan's own USDA hardiness band, zones 4aUSDA PHZM 2023
- Mandan's own 28°F hard-freeze dates, about May 2 and Oct 7 and the ~158-day span between themNOAA 1991–2020 Climate Normals
- 615 documented contamination sites on the federal record near Mandan, the closest Underground Storage Tanks record about 0.2 miles out from the town centreFederal environmental registers
- Mandan's boundary and the 8,651 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4a and a ~158-day seasonGrowable Ground crop-matching engine
- The ecoregion at Mandan's own centroid, the Northwestern Great PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Mandan's 8,651 acres read through its county's SSURGO summaryfrom Morton County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Morton County
- The growing challenges every North Dakota grower plans around — written at state scale, so they stay on the state guidefrom North Dakota
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Morton County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Mandan's 8,651 acreswhy one lot differs from the next →
- Which side of Mandan you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 8,651 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.2 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 Mandan-wide figureread your own land →
More in North Dakota
Wider growing context
What grows across North DakotaMandan sits outside our named growing regions, so North Dakota as a whole is its closest context here.
Nearby growing guides