Oregon · zones 6a–9a
When to plant watermelon in Oregon.
Sow between May 6 to Jun 22 in a typical year, keyed to Oregon's median last frost around Apr 15. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Watermelon dates for a typical Oregon season.
Direct sow
May 6 to Jun 22
Keyed to the ~Apr 15 last frost. Sow 1" deep, 36" apart.
Harvest
~85 days later
~20 lb per plant over ~3 weeks.
Oregon spans more than one climate: Zone 8 is the most common zone, but the state runs 6a to 9a. 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.