When to plant onion in zone 10b
A planting schedule for onion in USDA hardiness zone 10b, where the typical last spring frost is around Jan 9, 2026 and the first fall frost around Jan 5, 2026. Dates are computed from NOAA frost normals for a representative location (ZIP 90846) — your exact dates depend on your address.
Onion planting schedule for zone 10b
- Start seeds indoorsOct 30, 2025 – Dec 4, 2025
- Start hardening offJan 8, 2026 – Jan 22, 2026
- Transplant outdoorsJan 22, 2026 – Jan 29, 2026
Playing it safe with tender crops? Spring frost holds off until about Feb 19, 2026 in roughly 9 years out of 10.
Zone 10b covers a lot of ground. Enter your ZIP for onion dates worked out from your nearest weather station:
Free on one garden — no credit card. See the full onion growing guide or the whole zone 10b calendar.
Onion in other zones
More crops for zone 10b
Frost dates are NOAA 1991–2020 climate normals for a representative location (ZIP 90846) in zone 10b; your exact dates depend on your address. Schedules are guidance, not guarantees.