Plant Onions in Zone 4a
Seed-starting, transplant & harvest dates for USDA Zone 4a
Start indoors
Mar 1
Transplant
Apr 26
Harvest (~100d)
Aug 4
In Zone 4a, 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 10
First fall frost
Sep 22
Growing season
135 days
Full Onions grow guide → · All crops for Zone 4a →
Frequently asked questions
When should I start onions in Zone 4a?
Start onions seeds indoors around Mar 1 (Zone 4a).
Can I direct sow onions in Zone 4a?
Onions is best started indoors and transplanted in Zone 4a rather than direct sown.