Growing Onions in Zone 10
When to plant and harvest onions in Zone 10— based on your zone's frost dates.
Zone 10 sits just outside onions' ideal range (Zones 3–9), but a good harvest is achievable with careful timing and a little season extension.
Onions planting calendar for Zone 10
These months are derived from Zone 10's frost dates — last frost around Rare or none, first frost around Rare — December to January in coldest years.
Start indoors
December
Sow outdoors
—
Transplant
January
Harvest
June
Free planting calendar
Put onions on your own planting calendar
A month-by-month Zone 10 chart with onions already on it — add the rest of your garden, then print it or save it as a PDF.
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Onions care at a glance
- Sunlight
- Full sun
- Water
- 1 inch per week; stop as tops fall
- Spacing
- 4 in apart
- Days to maturity
- 90–120 days
- Best zones
- 3–9 (choose day-length type for your latitude)
Growing onions in Zone 10: FAQs
Can you grow onions in Zone 10?＋
Zone 10 sits just outside onions' ideal range (Zones 3–9), but a good harvest is achievable with careful timing and a little season extension.
When should I plant onions in Zone 10?＋
In Zone 10, start seeds indoors around December. Zone 10's last spring frost is typically Rare or none and its first fall frost around Rare — December to January in coldest years, which sets the planting window.
When to harvest onions in Zone 10?＋
Expect to harvest onions in Zone 10 around June, depending on the season and variety.
Full Onions guide →
Complete care, problems, companions, and harvest tips.
Zone 10 overview →
Frost dates, climate, and everything to grow here.
October in Zone 10 →
What to sow, transplant, and harvest this month.