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When to plant onions in Zone 6b

In Zone 6b, start indoors around January 15 – January 29 and transplant around March 19 – April 2.

Your onions timeline — Zone 6b

Start indoorsJanuary 15 – January 29
TransplantMarch 19 – April 2
Zone 6b last frost~04/23
Zone 6b first frost~10/20
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 6b'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

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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).

Onions in other zones

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