Iowa · zones 4b–6a
When to plant spinach in Iowa.
Sow between Mar 10 to Apr 21 in a typical year, keyed to Iowa's median last frost around May 1. A second, fall sowing fits Jul 24 to Sep 11. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Spinach dates for a typical Iowa season.
Direct sow
Mar 10 to Apr 21
Keyed to the ~May 1 last frost. Sow 0.5" deep, 3" apart.
Fall round
Jul 24 to Sep 11
Counted back from the ~Oct 7 first frost.
Harvest
~42 days later
~0.25 lb per plant over ~1 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.