Plant Onions in Zone 4b
Seed-starting, transplant & harvest dates for USDA Zone 4b
Start indoors
Feb 24
Transplant
Apr 21
Harvest (~100d)
Jul 30
In Zone 4b, 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 5
First fall frost
Sep 28
Growing season
146 days
Full Onions grow guide → · All crops for Zone 4b →
Frequently asked questions
When should I start onions in Zone 4b?
Start onions seeds indoors around Feb 24 (Zone 4b).
Can I direct sow onions in Zone 4b?
Onions is best started indoors and transplanted in Zone 4b rather than direct sown.