Tennessee · zones 7a–8a
When to plant onions in Tennessee.
Sow or transplant between Jan 29 to Mar 14 in a typical year, keyed to Tennessee's median last frost around Apr 8. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Onions dates for a typical Tennessee season.
1 · Start indoors
Dec 18 to Jan 31
About 6 weeks before set-out. Warm spot, real light.
2 · Set out
Jan 29 to Mar 14
Keyed to the ~Apr 8 last frost. Sow 0.5" deep, 4" apart.
Harvest
~95 days later
~0.5 lb per plant over ~1 weeks.
Tennessee spans more than one climate: Zone 7 is the most common zone, but the state runs 7a to 8a. 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.