Sedan, Montana, 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.
These conditions suit cabbage, cranberry, cilantro, and collard greens — a starting list any specific site will trim or extend with its own soil, sun, and drainage.
Even in Sedan, 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 Sedan 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 Sedan — soil, climate, flood, and parcel records. How we handle your address.
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Sedan — the short answer
Sedan, Montana: USDA zone 4b, about 120 days between hard freezes, across 39K acres of town.
- USDA zone
- 4b
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 24
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Sep 21
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~120
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Town area
- 39K 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 Sedan's average, not your lot's — a low corner or a tree line moves it. Against Sedan's 120-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Sedan
Each reading below is measured for Sedan itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredSedan runs about 120 days between hard freezes — a short growing season.
Long-maturing crops like melons, sweet potatoes, and winter squash can run out of runway before the first hard freeze, ripening late or not at all.
Lead with fast-maturing varieties, and stretch the season on both ends with cold frames, low tunnels, or a greenhouse.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredSedan 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 Sedan is in
Sedan sits in the Northwestern Great Plains — EPA Level III, inside the wider Great Plains. That is read at Sedan's own centroid, and it is not what its county reads: Gallatin County is mostly Middle Rockies. The wider page above you is answering a different question about different ground.
What Grows in Sedan
Every plant below cleared Sedan's own zone 4b and its 120-day season. Each card opens that plant's Montana profile. How we score.
Is it too late to plant in Sedan?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Apr 26; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 24 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Sep 21 — long-season crops need about 90 days of runway, quick greens only 30. Short seasons reward decisiveness — quick-maturing varieties late, hardy greens under cover, and next year’s garlic in the ground before it closes.
What's on the federal record near Sedan
Closest first, within ~10 miles of Sedan. Listing isn't leaking, and distance isn't exposure.
- ROBINSON RANCH INCUnderground Storage Tanks · 2.3 mi
- September Morn MineMining · 7.0 mi
- Pass Creek MineMining · 7.4 mi
- Mkb #7 AditMining · 7.7 mi
- Upper Cooper Adit MinesMining · 8.0 mi
- Lower Cooper AditMining · 8.1 mi
- SheridanMining · 8.6 mi
- Copper Pit Adit MineMining · 8.6 mi
- 01N07E20ABBA01Nitrate · 9.2 mi
Measured from Sedan'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 Sedan.
Severity Distribution
within ~10 miles of Sedan
Highest-Severity Sites
Know Before You Grow
- •Mine waste leaches heavy metals. Test for lead, arsenic and cadmium before growing food here.
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
Check your specific parcel in Sedan
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 Sedan average
Your land is one point inside Sedan
Everything above resolves to Sedan as a whole — one PHZM band and one 28°F frost record, read across 39K 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 Sedan Average
Sedan Average
- ●USDA Zones 4b, averaged across Sedan
- ●One soil character for all of Sedan
- ●Frost dates read at Sedan's scale: May 24 to Sep 21
YOUR Parcel
- ✓Your exact zone, not Sedan's 4b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Sedan
Pull a site-specific report for your exact address in Sedan, Montana — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Sedan averages can't show:
We read public map data around Sedan — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Sedan average
How we know this about Sedan
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 Sedan’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 Sedan
When does frost risk typically end in Sedan?
The last hard freeze (28°F) in Sedan typically lands around May 24, 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 Jun 14.
When is the first frost in Sedan?
The first hard freeze (28°F) in Sedan typically arrives around Sep 21, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 7, so the watching starts about Aug 22 — about 120 days after the spring freeze cleared.
How long is the growing season in Sedan?
Measured between 28°F hard freezes, Sedan sees about 120 frost-free days — roughly May 24 through Sep 21, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 14 to Sep 7, about 85 days.
Is the soil safe to grow vegetables in Sedan?
The federal record around Sedan is a meaningful one — 11 documented sites, mostly Mining entries (8), the nearest Underground Storage Tanks record about 2.3 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 gardeners stretch the season in Sedan?
With about 120 frost-free days between hard freezes, Sedan rewards the classic extension moves: floating row cover buys roughly two to four extra weeks at each shoulder — on this season that is a working window nearer 148 to 176 days — and cold frames or low tunnels buy more. Starting transplants indoors ahead of the May 24 hard-freeze normal stretches the season without touching the calendar.
Everything above is measured at Sedan's scale — its 4b band and its 120-day season. Your yard writes its own version of Sedan'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 Sedan’s own scale
6 of the readings below were taken at Sedan's own scale — its own ~120-day season between 28°F freezes, the 39,032 acres it covers and 11 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Sedan's own USDA hardiness band, zones 4bUSDA PHZM 2023
- Sedan's own 28°F hard-freeze dates, about May 24 and Sep 21 and the ~120-day span between themNOAA 1991–2020 Climate Normals
- 11 documented contamination sites on the federal record near Sedan, the closest Underground Storage Tanks record about 2.3 miles out from the town centreFederal environmental registers
- Sedan's boundary and the 39,032 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 4b and a ~120-day seasonGrowable Ground crop-matching engine
- Sedan sits in the Northwestern Great Plains — not the ecoregion its county mostly readsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Sedan's 39,032 acres read through its county's SSURGO summaryfrom Gallatin County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Gallatin County
- The growing challenges every Montana grower plans around — written at state scale, so they stay on the state guidefrom Montana
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Gallatin County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Sedan's 39,032 acreswhy one lot differs from the next →
- Which side of Sedan you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 39,032 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 2.3 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 Sedan-wide figureread your own land →
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