Plant Onions in Zone 10b
Seed-starting, transplant & harvest dates for USDA Zone 10b
Start indoors
Nov 6
Transplant
Jan 1
Harvest (~100d)
Apr 11
In Zone 10b, the average last spring frost is around January. Onions is a hardy crop, so give it a head start indoors about 10 weeks before that, then move it out after frost danger passes.
Last spring frost
Jan 15
First fall frost
Dec 31
Growing season
350 days
Full Onions grow guide → · All crops for Zone 10b →
Frequently asked questions
When should I start onions in Zone 10b?
Start onions seeds indoors around Nov 6 (Zone 10b).
Can I direct sow onions in Zone 10b?
Onions is best started indoors and transplanted in Zone 10b rather than direct sown.