Seymour, Iowa, sits in USDA hardiness zone 5b — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Expect cabbage, cranberry, lavender, and collard greens to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Even in Seymour, 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 Seymour 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 Seymour — soil, climate, flood, and parcel records. How we handle your address.
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Seymour — the short answer
Seymour, Iowa: USDA zone 5b, about 199 days between hard freezes, across 2K acres of city.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 9
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 25
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~199
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 2K 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 5b is Seymour's average, not your lot's — a low corner or a tree line moves it. Against Seymour's 199-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Seymour
Each reading below is measured for Seymour itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredSeymour runs about 199 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
MeasuredSeymour sits in USDA hardiness zone 5b.
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 Seymour is in
Seymour sits in the Central Irregular Plains — EPA Level III, inside the wider Great Plains. That is read at Seymour's own centroid rather than borrowed from Wayne County.
What Grows in Seymour
Every plant below cleared Seymour's own zone 5b and its 199-day season. Each card opens that plant's Iowa profile. How we score.
Is it too late to plant in Seymour?
Almost never — the real question is what to plant next. Cool-season crops can go in from around Mar 12; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 9 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 25 — long-season crops need about 90 days of runway, quick greens only 30. Even past midsummer there is room for a true fall garden here, and garlic planted near the close carries the momentum into next year.
What's on the federal record near Seymour
Closest first, within ~10 miles of Seymour. Listing isn't leaking, and distance isn't exposure.
- CASEY''S GENERAL STORE 1511Underground Storage Tanks · 250 ft
- SEYMOUR CONOCOUnderground Storage Tanks · 300 ft
- BOB''S FOOD MARKETUnderground Storage Tanks · 400 ft
- SEYMOUR HIGH SCHOOLBrownfields · 1300 ft
- SEYMOUR COMMUNITY SCHOOLUnderground Storage Tanks · 1400 ft
- JOHNSON OIL COUnderground Storage Tanks · 2100 ft
- 068N20W24AAB 19721 1967Nitrate · 1.0 mi
- 067N20W03CDNitrate · 4.3 mi
- 068N20W06DABA 17018 1964Nitrate · 4.6 mi
- MCDANIELS SERVICE STATIONUnderground Storage Tanks · 4.7 mi
- 069N20W32BB 1962Nitrate · 5.2 mi
- 069N20W21CC 1956Nitrate · 5.6 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Seymour'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 Seymour.
Total Sites
29
within ~10 miles of Seymour
Risk Level
Low
Highest-severity
1 concentrated animal feeding operation
Sources Checked
within ~10 miles of Seymour
Severity Distribution
within ~10 miles of Seymour
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Seymour, Nitrate runs higher than the national average — 20 sites within ~10 miles of Seymour. 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 Seymour
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 Seymour average
Your land is one point inside Seymour
Everything above resolves to Seymour as a whole — one PHZM band and one 28°F frost record, read across 2K 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 Seymour Average
Seymour Average
- ●USDA Zones 5b, averaged across Seymour
- ●One soil character for all of Seymour
- ●Frost dates read at Seymour's scale: Apr 9 to Oct 25
YOUR Parcel
- ✓Your exact zone, not Seymour's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Seymour
Pull a site-specific report for your exact address in Seymour, Iowa — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Seymour averages can't show:
We read public map data around Seymour — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Seymour average
How we know this about Seymour
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 Seymour’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 Seymour
When does frost risk typically end in Seymour?
The last hard freeze (28°F) in Seymour typically lands around Apr 9, 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 Apr 30.
When is the first frost in Seymour?
The first hard freeze (28°F) in Seymour typically arrives around Oct 25, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 11, so the watching starts about Sep 25 — about 199 days after the spring freeze cleared.
How long is the growing season in Seymour?
Measured between 28°F hard freezes, Seymour sees about 199 frost-free days — roughly Apr 9 through Oct 25, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 30 to Oct 11, about 164 days.
Is the soil safe to grow vegetables in Seymour?
The federal record around Seymour is light — 29 documented sites across the 9 federal source types we checked, mostly Nitrate entries (20), 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 Seymour?
From about Sep 25 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 25 (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 25. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Seymour's scale — its 5b band and its 199-day season. Your yard writes its own version of Seymour'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 Seymour’s own scale
6 of the readings below were taken at Seymour's own scale — its own ~199-day season between 28°F freezes, the 1,531 acres it covers and 29 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Seymour's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Seymour's own 28°F hard-freeze dates, about Apr 9 and Oct 25 and the ~199-day span between themNOAA 1991–2020 Climate Normals
- 29 documented contamination sites on the federal record near Seymour, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Seymour's boundary and the 1,531 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~199-day seasonGrowable Ground crop-matching engine
- The ecoregion at Seymour's own centroid, the Central Irregular PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Seymour's 1,531 acres read through its county's SSURGO summaryfrom Wayne County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Wayne County
- The growing challenges every Iowa grower plans around — written at state scale, so they stay on the state guidefrom Iowa
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Wayne County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Seymour's 1,531 acreswhy one lot differs from the next →
- Which side of Seymour you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,531 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 Seymour-wide figureread your own land →
More in Iowa
Wider growing context
What grows across IowaSeymour sits outside our named growing regions, so Iowa as a whole is its closest context here.
Nearby growing guides