Colo, 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.
Among the crops suited to this profile: cabbage, cranberry, lavender, and collard greens. The site-level story — soil, sun, drainage — decides the rest.
Even in Colo, 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 Colo 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 Colo — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Colo — the short answer
Colo, Iowa: USDA zone 5b, about 195 days between hard freezes, across 682 acres of city.
- USDA zone
- 5b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 11
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 23
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~195
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 682 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 Colo's average, not your lot's — a low corner or a tree line moves it. Against Colo's 195-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Colo
Each reading below is measured for Colo itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredColo runs about 195 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
MeasuredColo 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 Colo is in
Colo sits in the Western Corn Belt Plains — EPA Level III, inside the wider Great Plains. That is read at Colo's own centroid rather than borrowed from Story County.
What Grows in Colo
Every plant below cleared Colo's own zone 5b and its 195-day season. Each card opens that plant's Iowa profile. How we score.
Is it too late to plant in Colo?
Too late for some crops, right on time for others — a growing season is a sequence, not a deadline. Cool-season crops can go in from around Mar 14; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 11 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 23 — 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 Colo
Closest first, within ~10 miles of Colo. Listing isn't leaking, and distance isn't exposure.
- BOBS PAINT & REPAIRBrownfields · 450 ft
- STORY COUNTY CONSERVATIONUnderground Storage Tanks · 1400 ft
- STORY COUNTY ENGINEERUnderground Storage Tanks · 1500 ft
- MARK FARRENUnderground Storage Tanks · 1600 ft
- 083N21W08ADB 1915Colo 2Nitrate · 1700 ft
- WEIRS TRUCKSUnderground Storage Tanks · 2100 ft
- COLO COMM SCHOOLUnderground Storage Tanks · 2200 ft
- IDOT GARAGEUnderground Storage Tanks · 2300 ft
- CASEY''S GENERAL STORE #1413Underground Storage Tanks · 2600 ft
- FARMERS GRAIN COOPUnderground Storage Tanks · 0.5 mi
- FORMER PEMCO FAST BREAKUnderground Storage Tanks · 1.3 mi
- NORTHERN NATURAL GAS - COLO TBSBrownfields · 1.4 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Colo'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 Colo.
Total Sites
154
within ~10 miles of Colo
Risk Level
Moderate
Highest-severity
3 Toxics Release Inventory facilities
Sources Checked
within ~10 miles of Colo
Severity Distribution
within ~10 miles of Colo
Highest-Severity Sites
Know Before You Grow
- •Underground tanks leak petroleum as they age — near a former filling station, test the soil.
- •On a private well, test for nitrates: above 10 mg/L the water needs treatment before irrigating.
- •Near a brownfield, raised beds of imported soil give your food clean ground.
Check your specific parcel in Colo
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 Colo average
Your land is one point inside Colo
Everything above resolves to Colo as a whole — one PHZM band and one 28°F frost record, read across 682 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 Colo Average
Colo Average
- ●USDA Zones 5b, averaged across Colo
- ●One soil character for all of Colo
- ●Frost dates read at Colo's scale: Apr 11 to Oct 23
YOUR Parcel
- ✓Your exact zone, not Colo's 5b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Colo
Pull a site-specific report for your exact address in Colo, Iowa — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Colo averages can't show:
We read public map data around Colo — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Colo average
How we know this about Colo
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 Colo’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 Colo
When does frost risk typically end in Colo?
The last hard freeze (28°F) in Colo typically lands around Apr 11, 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 2.
When is the first frost in Colo?
The first hard freeze (28°F) in Colo typically arrives around Oct 23, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 9, so the watching starts about Sep 23 — about 195 days after the spring freeze cleared.
How long is the growing season in Colo?
Measured between 28°F hard freezes, Colo sees about 195 frost-free days — roughly Apr 11 through Oct 23, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 2 to Oct 9, about 160 days.
Is the soil safe to grow vegetables in Colo?
The federal record around Colo shows 154 documented sites, mostly Underground Storage Tanks entries (87), the nearest Brownfields 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 Colo?
From about Sep 23 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 23 (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 23. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Colo's scale — its 5b band and its 195-day season. Your yard writes its own version of Colo'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 Colo’s own scale
6 of the readings below were taken at Colo's own scale — its own ~195-day season between 28°F freezes, the 682 acres it covers and 154 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Colo's own USDA hardiness band, zones 5bUSDA PHZM 2023
- Colo's own 28°F hard-freeze dates, about Apr 11 and Oct 23 and the ~195-day span between themNOAA 1991–2020 Climate Normals
- 154 documented contamination sites on the federal record near Colo, the closest Brownfields record under a tenth of a mile out from the town centreFederal environmental registers
- Colo's boundary and the 682 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5b and a ~195-day seasonGrowable Ground crop-matching engine
- The ecoregion at Colo'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 Colo's 682 acres read through its county's SSURGO summaryfrom Story County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Story 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 Story County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Colo's 682 acreswhy one lot differs from the next →
- Which side of Colo you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 682 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Brownfields 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 Colo-wide figureread your own land →
More in Iowa
Wider growing context
What grows across IowaColo sits outside our named growing regions, so Iowa as a whole is its closest context here.
Nearby growing guides