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When to plant onions in Zone 9a

In Zone 9a, start indoors around November 24 – December 8 and transplant around January 26 – February 9.

Your onions timeline — Zone 9a

Start indoorsNovember 24 – December 8
TransplantJanuary 26 – February 9
Zone 9a last frost~03/02
Zone 9a first frost~11/25
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 9a'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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