Home › Crops › Onions › Zone 4b
When to plant onions in Zone 4b
In Zone 4b, start indoors around February 1 – February 15 and transplant around April 5 – April 19.
Your onions timeline — Zone 4b
| Start indoors | February 1 – February 15 |
|---|---|
| Transplant | April 5 – April 19 |
| Zone 4b last frost | ~05/10 |
| Zone 4b first frost | ~09/30 |
Start indoors; set out 4 weeks before the last frost. [src]Cited: University of New Hampshire Cooperative Extension — “Growing Vegetables: When to Plant Your Vegetable Garden”
Dates computed from Zone 4b's median NOAA frost normals and the cited rule. Your town may differ by a week or two — check your exact ZIP.
What you'll need
Affiliate links — as an Amazon Associate we may earn from qualifying purchases, at no extra cost to you.
Last verified 2026-07-16. Frost: NOAA NCEI 1991–2020. Zone: USDA 2023. Rule: University of New Hampshire Cooperative Extension — “Growing Vegetables: When to Plant Your Vegetable Garden”; UGA Extension (days to maturity).