What Growing Zone Is Iowa In?
USDA hardiness zones
5a to 5b
2023 USDA Plant Hardiness Zone Map
Iowa spans USDA hardiness zone 5a to 5b across its major population centers, according to the 2023 USDA Plant Hardiness Zone Map. That's a real range, not a single number: where you fall in it depends on where in the state you actually are.
Hardiness zone for ZIP 50309 (Des Moines)
Your USDA hardiness zone
Zone 5b
Avg. annual minimum (°F)
-15°F to -10°F
Avg. annual minimum (°C)
-26°C to -23°C
Nearest reference point: Des Moines, IA
This is a regional estimate based on the nearest of 826 reference points, each matched to the official 2023 USDA zone map. It’s accurate to within about a half-zone across most of the country, but elevation shifts zones over short distances, so if you’re in mountainous terrain, check the official USDA map for your exact address (see Sources below).
Iowa's USDA Hardiness Zones
Here's how the zone shifts across Iowa's major cities:
For your exact zone by ZIP code, use the Hardiness Zone Finder, and for what a zone number actually measures (and doesn't), see how zones actually work.
Frost Dates in Iowa
Because Iowa sits in a single zone, frost dates are consistent statewide:
- Zone 5: average last frost Apr 8 - Apr 22, average first frost Oct 8 - Oct 22.
These are averages, not guarantees. For your specific frost window, use the Frost Date Calculator. For a full vegetable-by-vegetable planting calendar already calculated from Iowa's frost dates, see the Iowa Planting Calendar.
Iowa State University horticulturist Richard Jauron has noted that hardiness can vary meaningfully within the same zone band -- microclimate factors like wind exposure and snow cover can make the difference between success and winterkill for a borderline-hardy plant even between towns like Mason City and Ames.
What Grows Well in Iowa's Zones
A few real, zone-appropriate picks recommended by Iowa State University Extension and Outreach for Iowa landscapes: not an exhaustive list, but a genuine starting point.
- Meserve hybrid holly (Ilex x meserveae)
- Oregon grapeholly (Mahonia aquifolium)
- Hybrid boxwood (Buxus hybrids)
- Catawba rhododendron (Rhododendron catawbiense)
- PJM rhododendron (Rhododendron PJM hybrids)
Ready to find your exact zone? Use the Hardiness Zone Finder: enter your ZIP code for a precise match against the 2023 USDA map.
Iowa Growing Zone FAQ
What growing zone is Iowa in?
Iowa spans USDA hardiness zones 5a to 5b on the 2023 USDA Plant Hardiness Zone Map. Sioux City is zone 5a and Dubuque is zone 5a; enter your ZIP code in the Hardiness Zone Finder for your exact zone.
What growing zone is Des Moines, IA?
Des Moines is in USDA hardiness zone 5b on the 2023 USDA map. Zones within a city can differ by half a zone, so check your ZIP code for an exact match.
What growing zone is Sioux City, IA?
Sioux City is in USDA hardiness zone 5a on the 2023 USDA map. Zones within a city can differ by half a zone, so check your ZIP code for an exact match.
What growing zone is Dubuque, IA?
Dubuque is in USDA hardiness zone 5a on the 2023 USDA map. Zones within a city can differ by half a zone, so check your ZIP code for an exact match.
What growing zone is Davenport, IA?
Davenport is in USDA hardiness zone 5b on the 2023 USDA map. Zones within a city can differ by half a zone, so check your ZIP code for an exact match.
Free book · 23 pages, PDF
The Spacing & Planting Cheat Sheet
When to start, when to plant, how far apart.
Sources & further reading
Zone and city data checked against the official USDA Plant Hardiness Zone Map. Plant recommendations sourced from Iowa State University Extension and Outreach. Climate note sourced from Iowa State University Extension and Outreach. For more on how we build and verify reference data across this site, see our methodology page.
Growing zones in nearby states
Gardening near a state line? Zones don't stop at the border:
- Illinois growing zones
- Missouri growing zones
- Wisconsin growing zones
- Minnesota growing zones
- Nebraska growing zones
- South Dakota growing zones
Or browse all 51 state growing-zone guides.