Plant Onions in Zone 3b
Seed-starting, transplant & harvest dates for USDA Zone 3b
Start indoors
Mar 4
Transplant
Apr 29
Harvest (~100d)
Aug 7
In Zone 3b, the average last spring frost is around May. 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
May 13
First fall frost
Sep 18
Growing season
128 days
Full Onions grow guide → · All crops for Zone 3b →
Frequently asked questions
When should I start onions in Zone 3b?
Start onions seeds indoors around Mar 4 (Zone 3b).
Can I direct sow onions in Zone 3b?
Onions is best started indoors and transplanted in Zone 3b rather than direct sown.