Worth County, in Iowa, sits in USDA hardiness zone 5a — a band that supports both cool-season staples and warm-season crops chosen to fit the local frost window.
Expect sweet corn, tomato, apple, and hosta to be strong candidates here; the deciding factors on any one parcel stay local — soil, sun, and drainage.
Grounded in USDA PHZM 2023 · Growable Ground suitability scoring · NOAA 1991–2020 Climate Normals
Worth County holds more than one microclimate.
Soils and elevations shift across Worth County, so your frost dates and drainage aren't the county average. Enter your address and we'll score 1,112 plants against your land's actual soil, sun, and frost.
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
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Quick Facts
USDA Zones
5a
Last Hard Freeze (28°F)
Apr 7
County normal — light frosts run a few weeks later
First Hard Freeze (28°F)
Oct 30
County normal — light frosts arrive a few weeks earlier
County Area
256K acres
Hardiness Zone Range
Zone maps are averages across Worth County. Your yard's slope, trees, and frost pockets shift what actually grows — see your land's exact reading.
Soil in Worth County
Across Worth County, the ground is predominantly Mollisols, where Webster, Klinger, and Nicollet are the most extensive named soil series. The soil is generally poorly drained with a loam surface. Topsoil pH runs about 6.2–6.8, slightly acidic. Rainfall drains through hydrologic group C/D soils.
Soil order
Mollisols
Drainage
Poorly drained
Prime farmland
47%
Hydric soils
41%
Soil still varies lot by lot — soil types explained.
What Grows in Worth County
Plants matched to Worth County's USDA zones 5a — each links to its full growing profile.
Is it too late to plant in Worth County?
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 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 30 — 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.
Growing Challenges in Iowa
What an experienced grower plans around here — each one has a move.
Cold winters reaching -20F or below
Choose perennials rated a zone hardier than yours — Iowa winters test the margins, and the margin is where plants are lost.
Variable spring weather delays planting
Let soil temperature and your local frost normal call the start, not the calendar — a two-week wait beats a replant.
Wind exposure on open prairies desiccates plants
Even a simple windbreak — a shrub row, a snow fence, a tall cover crop — cuts wind desiccation dramatically.
For cultivar selection, pest pressure, and planting-time guidance specific to Iowa, the Iowa State University Extension and Outreach is the authoritative local source.
Safe to Grow Here?
What the federal record shows across Worth County — and how to grow with it.
We checked the federal record across Worth County — 107 documented sites across 5 of the 9 source types we track.
The most significant on record: 9 Toxics Release Inventory facilities. Active industrial facilities reporting chemical releases to air, water, and land.
The federal record across Worth County is a modest one — a typical footprint for a growing area. Nothing here calls for alarm; it's worth knowing which recorded sites sit closest to where you grow, and each one on the map carries its type and location. If one turns out to be a near neighbor, a one-time soil test settles the question.
Sources: EPA, USGS — 1.8M documented sites tracked nationwide across 9 federal source types.
Environmental Intelligence
Understanding what's nearby helps you make informed decisions about where and how to grow.
Total Sites
107
across Worth County
Risk Level
Moderate
Highest-severity
9 Toxics Release Inventory facilities
Sources Checked
across Worth County
Severity Distribution
across Worth County
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Worth County, Toxic Release Inventory runs higher than the national average — 9 sites nearby. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Toxic 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 Worth County
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,112 plant recommendations.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
Your Specific Parcel Matters
Worth County Average
- ●USDA Zones 5a
- ●Generic soil type for the area
- ●State-average frost dates
YOUR Parcel
- ✓Your exact hardiness zone
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your parcel in Worth County
Pull a site-specific report for your exact address in Worth County, Iowa — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your exact spot that zone averages miss:
We read public map data for this spot — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources analyzed in seconds
Key Growing Facts for Worth County, Iowa
- USDA Hardiness Zones: 5a (USDA PHZM 2023)
- Last Hard Freeze (28°F): Apr 7 (county normal, NOAA 1991–2020 Climate Normals — light frosts can follow for a few weeks)
- First Hard Freeze (28°F): Oct 30 (county normal, NOAA 1991–2020 Climate Normals — light frosts can arrive a few weeks earlier)
- Days Between Hard Freezes: ~206 (county normal, NOAA 1991–2020 Climate Normals)
- County Land Area: 256K acres (US Census TIGER 2025)
Zone data: USDA ARS Plant Hardiness Zone Map 2023. Climate data: NOAA NCEI. County boundaries: US Census TIGER/Line 2025.
Frost dates here are the Worth County average. Low spots and tree cover move them by days on any one yard — see your exact frost windows.
Frequently Asked Questions
What hardiness zone is Worth County, Iowa?
Worth County sits in USDA hardiness zone 5a, per the USDA Plant Hardiness Zone Map 2023. Zones reflect average annual extreme minimum temperatures from 1991–2020 weather data.
Is it too late to plant in Worth County?
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 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 30 — 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.
When does frost risk typically end in Worth County?
The last hard freeze (28°F) in Worth County typically lands around Apr 7, per NOAA 1991–2020 climate normals — an earlier marker than the light-frost dates many planting charts quote. That marks the hard freeze, not the last light frost — light frosts can still bite for a few more weeks, so tender transplants usually wait another 2–3 weeks.
How long is the growing season in Worth County?
Measured between 28°F hard freezes, Worth County sees about 206 frost-free days — roughly Apr 7 through Oct 30, per NOAA 1991–2020 climate normals. Tender crops get a somewhat shorter practical window, since lighter frosts reach a few weeks past the hard-freeze dates on both ends.
What vegetables grow in Worth County?
Worth County's zone 5a supports a wide range — strong performers include Sweet Corn, Tomato, Apple, and Hosta. What actually takes on any one site comes down to its soil, sun, and drainage, and we score each plant against the real conditions at your address.
Which hardiness zone is Worth County, really?
Officially, Worth County sits in USDA zone 5a (USDA PHZM 2023) — but a zone is a 30-year average of winter's coldest night across an area, and it can't see any one yard. A south-facing slope, a tree line, or a low frost pocket can shift a single site by half a zone either way, which is why neighboring gardeners often quote different numbers. We read the conditions at your exact address — soil, sun, slope, and frost — and score 1,112 plants against what's actually there.
Is the soil safe to grow vegetables in Worth County?
The federal record around Worth County shows 107 documented sites — 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.
Just moved to Worth County — what should I know before planting?
Start with three facts. Worth County sits in USDA zone 5a, which sets what survives winter; the last 28°F hard freeze typically clears around Apr 7, with about 206 frost-free days to work with (NOAA 1991–2020 climate normals); and 107 documented sites sit on the federal record — a typical footprint for a growing area, worth a look on the contamination map before food beds. From there, matching plants to your actual soil and sun is the fun part.
Everything on this page is a Worth County average. Your yard writes its own version — we read soil, sun, drainage, and frost at your exact address. Try it for 14 days — no card required.
Will It Grow Here?
Zone fit is the first question — each answer below reads Iowa's frost window, season length, and soil profile against the plant's real requirements.