Calvin, North Dakota, sits in USDA hardiness zone 3b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
Growers here do well with cabbage, cranberry, turkish rocket, and collard greens — with the usual caveat that any single yard's soil, sun, and drainage cast the deciding vote.
Even in Calvin, 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 Calvin 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 Calvin — soil, climate, flood, and parcel records. How we handle your address.
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Calvin — the short answer
Calvin, North Dakota: USDA zone 3b, about 150 days between hard freezes, across 140 acres of city.
- USDA zone
- 3b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 7
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 4
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~150
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 140 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 3b is Calvin's average, not your lot's — a low corner or a tree line moves it. Against Calvin's 150-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Calvin
Each reading below is measured for Calvin itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredCalvin runs about 150 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
MeasuredCalvin sits in USDA hardiness zone 3b.
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 Calvin is in
Calvin sits in the Northern Glaciated Plains — EPA Level III, inside the wider Great Plains. That is read at Calvin's own centroid rather than borrowed from Cavalier County.
What Grows in Calvin
Every plant below cleared Calvin's own zone 3b and its 150-day season. Each card opens that plant's North Dakota profile. How we score.
Is it too late to plant in Calvin?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Apr 9; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 7 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 4 — 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 Calvin
Closest first, within ~10 miles of Calvin. Listing isn't leaking, and distance isn't exposure.
- Farmers Union OilUnderground Storage Tanks · 400 ft
- Border Central SchoolUnderground Storage Tanks · 900 ft
- 162-064-15CBCNitrate · 900 ft
- 162-064-14DCCNitrate · 1.7 mi
- 162-064-09AAA1Nitrate · 1.7 mi
- 162-063-17AAANitrate · 5.1 mi
- 162-063-21BBBNitrate · 5.2 mi
- 163-064-21AADNitrate · 5.6 mi
- Clyde Farm Service IncUnderground Storage Tanks · 5.7 mi
- 163-063-30BABNitrate · 5.8 mi
- 162-063-15CCCNitrate · 6.2 mi
- 161-064-22BAANitrate · 6.3 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Calvin'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 Calvin.
Severity Distribution
within ~10 miles of Calvin
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Calvin, Nitrate runs higher than the national average — 42 sites within ~10 miles of Calvin. 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 Calvin
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 Calvin average
Your land is one point inside Calvin
Everything above resolves to Calvin as a whole — one PHZM band and one 28°F frost record, read across 140 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 Calvin Average
Calvin Average
- ●USDA Zones 3b, averaged across Calvin
- ●One soil character for all of Calvin
- ●Frost dates read at Calvin's scale: May 7 to Oct 4
YOUR Parcel
- ✓Your exact zone, not Calvin's 3b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Calvin
Pull a site-specific report for your exact address in Calvin, North Dakota — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Calvin averages can't show:
We read public map data around Calvin — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Calvin average
How we know this about Calvin
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 Calvin’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 Calvin
When does frost risk typically end in Calvin?
The last hard freeze (28°F) in Calvin typically lands around May 7, 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 28.
When is the first frost in Calvin?
The first hard freeze (28°F) in Calvin typically arrives around Oct 4, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 20, so the watching starts about Sep 4 — about 150 days after the spring freeze cleared.
How long is the growing season in Calvin?
Measured between 28°F hard freezes, Calvin sees about 150 frost-free days — roughly May 7 through Oct 4, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 28 to Sep 20, about 115 days.
Is the soil safe to grow vegetables in Calvin?
The federal record around Calvin is light — 45 documented sites across the 9 federal source types we checked, mostly Nitrate entries (42), the nearest Underground Storage Tanks record under a tenth of a mile out — and proximity to a documented site is information, not a diagnosis of any one yard. Growing food here starts from a strong position; a soil test before new food beds settles any site-specific question.
How do I protect my plants from frost in Calvin?
From about Sep 4 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 4 (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 4. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Calvin's scale — its 3b band and its 150-day season. Your yard writes its own version of Calvin'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 Calvin’s own scale
6 of the readings below were taken at Calvin's own scale — its own ~150-day season between 28°F freezes, the 140 acres it covers and 45 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Calvin's own USDA hardiness band, zones 3bUSDA PHZM 2023
- Calvin's own 28°F hard-freeze dates, about May 7 and Oct 4 and the ~150-day span between themNOAA 1991–2020 Climate Normals
- 45 documented contamination sites on the federal record near Calvin, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Calvin's boundary and the 140 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 3b and a ~150-day seasonGrowable Ground crop-matching engine
- The ecoregion at Calvin's own centroid, the Northern Glaciated PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Calvin's 140 acres read through its county's SSURGO summaryfrom Cavalier County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Cavalier 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 Cavalier County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Calvin's 140 acreswhy one lot differs from the next →
- Which side of Calvin you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 140 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks 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 Calvin-wide figureread your own land →
More in North Dakota
Wider growing context
What grows across North DakotaCalvin sits outside our named growing regions, so North Dakota as a whole is its closest context here.