Swisher, Iowa, sits in USDA hardiness zone 5a — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
On paper, cabbage, cranberry, lavender, and collard greens all suit these conditions — on the ground, soil, sun, and drainage make the final call.
Even in Swisher, 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 Swisher 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 Swisher — soil, climate, flood, and parcel records. How we handle your address.
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Swisher — the short answer
Swisher, Iowa: USDA zone 5a, about 191 days between hard freezes, across 598 acres of city.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 13
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 21
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~191
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 598 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 5a is Swisher's average, not your lot's — a low corner or a tree line moves it. Against Swisher's 191-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Swisher
Each reading below is measured for Swisher itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredSwisher runs about 191 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
MeasuredSwisher sits in USDA hardiness zone 5a.
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 Swisher is in
Swisher sits in the Western Corn Belt Plains — EPA Level III, inside the wider Great Plains. That is read at Swisher's own centroid rather than borrowed from Johnson County.
What Grows in Swisher
Every plant below cleared Swisher's own zone 5a and its 191-day season. Each card opens that plant's Iowa profile. How we score.
Is it too late to plant in Swisher?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Mar 16; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 13 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 21 — 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 Swisher
Closest first, within ~10 miles of Swisher. Listing isn't leaking, and distance isn't exposure.
- JEFFERSON-MONROE FIRE DEPT INCUnderground Storage Tanks · 250 ft
- FORMER D&G OIL CORPUnderground Storage Tanks · 500 ft
- RIVERSIDE SPORTS CARSBrownfields · 500 ft
- BROADMOOR FARMS LTDUnderground Storage Tanks · 800 ft
- CORALVILLE WILDLIFE UNITUnderground Storage Tanks · 800 ft
- JOHNSON COUNTYUnderground Storage Tanks · 800 ft
- KIRACOFE OIL CO INCUnderground Storage Tanks · 1.0 mi
- 380 BPUnderground Storage Tanks · 1.6 mi
- KIRACOFE STATIONUnderground Storage Tanks · 1.6 mi
- 081N07W16CBCB 17311 1964Nitrate · 1.7 mi
- 082N07W33CAC IA Highway CommissionNitrate · 2.0 mi
- J-70 CHRIS BOWERSOXToxics Release Inventory · 2.1 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Swisher'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 Swisher.
Total Sites
810
within ~10 miles of Swisher
Risk Level
Elevated
Highest-severity
63 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Swisher
Severity Distribution
within ~10 miles of Swisher
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Swisher, Toxics Release Inventory runs higher than the national average — 63 sites within ~10 miles of Swisher. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Toxics Release Inventory: TRI facilities report annual chemical releases to air, water, and land.
Check prevailing wind direction — downwind parcels face higher exposure than upwind or crosswind locations.
Check your specific parcel in Swisher
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 Swisher average
Your land is one point inside Swisher
Everything above resolves to Swisher as a whole — one PHZM band and one 28°F frost record, read across 598 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 Swisher Average
Swisher Average
- ●USDA Zones 5a, averaged across Swisher
- ●One soil character for all of Swisher
- ●Frost dates read at Swisher's scale: Apr 13 to Oct 21
YOUR Parcel
- ✓Your exact zone, not Swisher's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Swisher
Pull a site-specific report for your exact address in Swisher, Iowa — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Swisher averages can't show:
We read public map data around Swisher — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Swisher average
How we know this about Swisher
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 Swisher’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 Swisher
When does frost risk typically end in Swisher?
The last hard freeze (28°F) in Swisher typically lands around Apr 13, 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 4.
When is the first frost in Swisher?
The first hard freeze (28°F) in Swisher typically arrives around Oct 21, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 7, so the watching starts about Sep 21 — about 191 days after the spring freeze cleared.
How long is the growing season in Swisher?
Measured between 28°F hard freezes, Swisher sees about 191 frost-free days — roughly Apr 13 through Oct 21, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 4 to Oct 7, about 156 days.
Is the soil safe to grow vegetables in Swisher?
The federal record around Swisher is a meaningful one — 810 documented sites, mostly Underground Storage Tanks entries (360), the nearest Underground Storage Tanks record under a tenth of a mile 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 Swisher?
From about Sep 21 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 21 (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 21. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Swisher's scale — its 5a band and its 191-day season. Your yard writes its own version of Swisher'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 Swisher’s own scale
6 of the readings below were taken at Swisher's own scale — its own ~191-day season between 28°F freezes, the 598 acres it covers and 810 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Swisher's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Swisher's own 28°F hard-freeze dates, about Apr 13 and Oct 21 and the ~191-day span between themNOAA 1991–2020 Climate Normals
- 810 documented contamination sites on the federal record near Swisher, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Swisher's boundary and the 598 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~191-day seasonGrowable Ground crop-matching engine
- The ecoregion at Swisher's own centroid, the Western Corn Belt PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Swisher's 598 acres read through its county's SSURGO summaryfrom Johnson County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Johnson 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 Johnson County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Swisher's 598 acreswhy one lot differs from the next →
- Which side of Swisher you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 598 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 Swisher-wide figureread your own land →
More in Iowa
Wider growing context
What grows across IowaSwisher sits outside our named growing regions, so Iowa as a whole is its closest context here.
Nearby growing guides