Iowa · zones 4b–6a
When to plant green beans in Iowa.
Sow between May 1 to Jun 21 in a typical year, keyed to Iowa's median last frost around May 1. A second, fall sowing fits Jun 23 to Jul 26. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Green Beans dates for a typical Iowa season.
Direct sow
May 1 to Jun 21
Keyed to the ~May 1 last frost. Sow 1" deep, 3" apart.
Fall round
Jun 23 to Jul 26
Counted back from the ~Oct 7 first frost.
Harvest
~55 days later
~0.75 lb per plant over ~3 weeks.
Iowa spans more than one climate: Zone 5 is the most common zone, but the state runs 4b to 6a. That's why the planner works from your ZIP code's frost dates, not your zone — mountain and coastal gardens in the same state can be three weeks apart.