Oklahoma · zones 6b–7b
When to plant sweet corn in Oklahoma.
Sow between Apr 6 to Jul 6 in a typical year, keyed to Oklahoma's median last frost around Mar 30. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Sweet Corn dates for a typical Oklahoma season.
Direct sow
Apr 6 to Jul 6
Keyed to the ~Mar 30 last frost. Sow 1.5" deep, 12" apart.
Harvest
~75 days later
~1 lb per plant over ~1 weeks.
Oklahoma spans more than one climate: Zone 7 is the most common zone, but the state runs 6b to 7b. 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.