Columbus Junction, Iowa, sits in USDA hardiness zone 5b — a zone band wide enough that plant choice, not possibility, is the interesting question.
Reliable performers under these conditions include cabbage, cranberry, lavender, and collard greens; what your own ground favors still comes down to its soil, sun, and drainage.
Even in Columbus Junction, 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 Columbus Junction 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 Columbus Junction — soil, climate, flood, and parcel records. How we handle your address.
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Columbus Junction — the short answer
Columbus Junction, Iowa: USDA zone 5b, about 204 days between hard freezes, across 1K acres of city.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 7
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 28
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~204
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 1K 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 Columbus Junction's average, not your lot's — a low corner or a tree line moves it. Against Columbus Junction's 204-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Columbus Junction
Each reading below is measured for Columbus Junction itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredColumbus Junction runs about 204 days between hard freezes — a long growing season.
There is slack for succession plantings and slow-finishing crops: many vegetables can be sown twice, and the heat-lovers have time to ripen fully.
Plan a second sowing of quick crops after the first comes out, and use the fall window most gardeners let sit idle.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredColumbus Junction 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 Columbus Junction is in
Columbus Junction sits in the Western Corn Belt Plains — EPA Level III, inside the wider Great Plains. That is read at Columbus Junction's own centroid, and it is not what its county reads: Louisa County is mostly Interior River Valleys and Hills. The wider page above you is answering a different question about different ground.
What Grows in Columbus Junction
Every plant below cleared Columbus Junction's own zone 5b and its 204-day season. Each card opens that plant's Iowa profile. How we score.
Is it too late to plant in Columbus Junction?
Rarely: the season closes in stages, not all at once, and each stage has its crops. Cool-season crops can go in from around Mar 10; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 7 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 28 — long-season crops need about 90 days of runway, quick greens only 30. With a season this long, “too late” mostly means “switch crops” — second sowings and a full fall garden are the norm, with garlic closing the year.
What's on the federal record near Columbus Junction
Closest first, within ~10 miles of Columbus Junction. Listing isn't leaking, and distance isn't exposure.
- CECIL''S STANDARDUnderground Storage Tanks · 200 ft
- NATURAL GAS PIPELINE CO OF AMERICAUnderground Storage Tanks · 500 ft
- L-W SERVICE COUnderground Storage Tanks · 500 ft
- MORGAN STORAGEUnderground Storage Tanks · 700 ft
- 075N04W19CCAB 38230 1935Columbus Junction NorthNitrate · 850 ft
- LOUISA OIL COUnderground Storage Tanks · 1000 ft
- 075N04W19DCAB 02977 1947Columbus Junction SouthNitrate · 2000 ft
- CASEY''S GENERAL STORE 2659Underground Storage Tanks · 2000 ft
- 075N04W19DCAA 23192 1972Columbus Junction EastNitrate · 2300 ft
- FORMER IDOT MAINTENANCE FACILITYUnderground Storage Tanks · 0.5 mi
- TWO RIVERS MARKETUnderground Storage Tanks · 0.5 mi
- CONTELUnderground Storage Tanks · 0.7 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Columbus Junction'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 Columbus Junction.
Total Sites
121
within ~10 miles of Columbus Junction
Risk Level
Moderate
Highest-severity
1 Toxics Release Inventory facility
Sources Checked
within ~10 miles of Columbus Junction
Severity Distribution
within ~10 miles of Columbus Junction
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Columbus Junction, Nitrate runs higher than the national average — 86 sites within ~10 miles of Columbus Junction. 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 Columbus Junction
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 Columbus Junction average
Your land is one point inside Columbus Junction
Everything above resolves to Columbus Junction as a whole — one PHZM band and one 28°F frost record, read across 1K 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 Columbus Junction Average
Columbus Junction Average
- ●USDA Zones 5b, averaged across Columbus Junction
- ●One soil character for all of Columbus Junction
- ●Frost dates read at Columbus Junction's scale: Apr 7 to Oct 28
YOUR Parcel
- ✓Your exact zone, not Columbus Junction's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Columbus Junction
Pull a site-specific report for your exact address in Columbus Junction, Iowa — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Columbus Junction averages can't show:
We read public map data around Columbus Junction — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Columbus Junction average
How we know this about Columbus Junction
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 Columbus Junction’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 Columbus Junction
When does frost risk typically end in Columbus Junction?
The last hard freeze (28°F) in Columbus Junction typically lands around Apr 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 Apr 28.
When is the first frost in Columbus Junction?
The first hard freeze (28°F) in Columbus Junction typically arrives around Oct 28, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 14, so the watching starts about Sep 28 — about 204 days after the spring freeze cleared.
How long is the growing season in Columbus Junction?
Measured between 28°F hard freezes, Columbus Junction sees about 204 frost-free days — roughly Apr 7 through Oct 28, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Apr 28 to Oct 14, about 169 days.
Is the soil safe to grow vegetables in Columbus Junction?
The federal record around Columbus Junction shows 121 documented sites, mostly Nitrate entries (86), the nearest Underground Storage Tanks record under a tenth of a mile out — a typical footprint for a growing area, and proximity to a documented site is information, not a diagnosis of any one yard. It's worth seeing which recorded sites sit closest to where you grow, and testing the soil before new food beds near any of them.
How do I protect my plants from frost in Columbus Junction?
From about Sep 28 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 28 (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 28. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Columbus Junction's scale — its 5b band and its 204-day season. Your yard writes its own version of Columbus Junction'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 Columbus Junction’s own scale
6 of the readings below were taken at Columbus Junction's own scale — its own ~204-day season between 28°F freezes, the 1,374 acres it covers and 121 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Columbus Junction's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Columbus Junction's own 28°F hard-freeze dates, about Apr 7 and Oct 28 and the ~204-day span between themNOAA 1991–2020 Climate Normals
- 121 documented contamination sites on the federal record near Columbus Junction, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Columbus Junction's boundary and the 1,374 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~204-day seasonGrowable Ground crop-matching engine
- Columbus Junction sits in the Western Corn Belt 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 Columbus Junction's 1,374 acres read through its county's SSURGO summaryfrom Louisa County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Louisa 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 Louisa County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Columbus Junction's 1,374 acreswhy one lot differs from the next →
- Which side of Columbus Junction you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 1,374 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 Columbus Junction-wide figureread your own land →