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When to Plant Onions in California

California spans USDA hardiness 5b to 11a (zones 5b to 11a on this page). Plant onions by your local frost date, not the calendar — pick your zone below for exact start-indoors, transplant, and harvest dates.

Jump to: Zone 5b · Zone 6a · Zone 6b · Zone 7a · Zone 7b · Zone 8a · Zone 8b · Zone 9a · Zone 9b · Zone 10a · Zone 10b · Zone 11a

Onions planting calendar for California, Zone 5b

Average last spring frost

April 30

Average first fall frost

October 5

🌿

Direct sow

Feb 5

🌾

Projected first harvest

May 26

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🌱 Start indoors🌿 Growing outside🌾 HarvestTodayZone 5b (approximate)

Most onions mature in about 90 to 110 days depending on the variety. Full zone 5 guide (both 5a and 5b) →

Onions planting calendar for California, Zone 6a

Average last spring frost

April 25

Average first fall frost

October 10

🌿

Direct sow

Jan 31

🌾

Projected first harvest

May 21

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🌱 Start indoors🌿 Growing outside🌾 HarvestTodayZone 6a (approximate)

Most onions mature in about 90 to 110 days depending on the variety. Full zone 6 guide (both 6a and 6b) →

Onions planting calendar for California, Zone 6b

Average last spring frost

April 20

Average first fall frost

October 15

🌿

Direct sow

Jan 26

🌾

Projected first harvest

May 16

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🌱 Start indoors🌿 Growing outside🌾 HarvestTodayZone 6b (approximate)

Most onions mature in about 90 to 110 days depending on the variety. Full zone 6 guide (both 6a and 6b) →

Onions planting calendar for California, Zone 7a

Average last spring frost

April 15

Average first fall frost

October 20

🌿

Direct sow

Jan 21

🌾

Projected first harvest

May 11

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🌱 Start indoors🌿 Growing outside🌾 HarvestTodayZone 7a (approximate)

Most onions mature in about 90 to 110 days depending on the variety. Full zone 7 guide (both 7a and 7b) →

Onions planting calendar for California, Zone 7b

Average last spring frost

April 10

Average first fall frost

October 30

🌿

Direct sow

Jan 16

🌾

Projected first harvest

May 6

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🌱 Start indoors🌿 Growing outside🌾 HarvestTodayZone 7b (approximate)

Most onions mature in about 90 to 110 days depending on the variety. Full zone 7 guide (both 7a and 7b) →

Onions planting calendar for California, Zone 8a

Average last spring frost

April 1

Average first fall frost

November 10

🌿

Direct sow

Jan 7

🌾

Projected first harvest

Apr 27

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🌱 Start indoors🌿 Growing outside🌾 HarvestTodayZone 8a (approximate)

Most onions mature in about 90 to 110 days depending on the variety. Full zone 8 guide (both 8a and 8b) →

Onions planting calendar for California, Zone 8b

Average last spring frost

March 20

Average first fall frost

November 20

🌿

Direct sow

Dec 26

🌾

Projected first harvest

Apr 15

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🌱 Start indoors🌿 Growing outside🌾 HarvestTodayZone 8b (approximate)

Most onions mature in about 90 to 110 days depending on the variety. Full zone 8 guide (both 8a and 8b) →

Onions planting calendar for California, Zone 9a

Average last spring frost

March 1

Average first fall frost

December 1

🌿

Direct sow

Dec 7

🌾

Projected first harvest

Mar 27

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🌱 Start indoors🌿 Growing outside🌾 HarvestTodayZone 9a (approximate)

Most onions mature in about 90 to 110 days depending on the variety. Full zone 9 guide (both 9a and 9b) →

Onions planting calendar for California, Zone 9b

Average last spring frost

February 15

Average first fall frost

December 15

🌿

Direct sow

Nov 23

🌾

Projected first harvest

Mar 13

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🌱 Start indoors🌿 Growing outside🌾 HarvestTodayZone 9b (approximate)

Most onions mature in about 90 to 110 days depending on the variety. Full zone 9 guide (both 9a and 9b) →

Onions planting calendar for California, Zone 10a

Average last spring frost

January 30

Average first fall frost

December 30

🌿

Direct sow

Nov 7

🌾

Projected first harvest

Feb 25

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🌱 Start indoors🌿 Growing outside🌾 HarvestTodayZone 10a (approximate)

Most onions mature in about 90 to 110 days depending on the variety. Full zone 10 guide (both 10a and 10b) →

Onions planting calendar for California, Zone 10b

Average last spring frost

January 30

Average first fall frost

December 30

🌿

Direct sow

Nov 7

🌾

Projected first harvest

Feb 25

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🌱 Start indoors🌿 Growing outside🌾 HarvestTodayZone 10b (approximate)

Most onions mature in about 90 to 110 days depending on the variety. Full zone 10 guide (both 10a and 10b) →

Onions planting calendar for California, Zone 11a

Zone 11a doesn't get a seasonal frost — onions plants on a warm/cool-season calendar instead of frost dates.

🗓️

Best planting window

Year-round

🌾

Time to harvest

~110 days

🌴 Your zone never frosts, so planting is timed to the cooler vs. warmer seasons rather than a frost date.

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🌿 Planting windowTodayZone 11a: frost-free; timed to seasons, not frost

Most onions mature in about 90 to 110 days depending on the variety.

Not sure which half-zone you're in? Set your ZIP in HomeSown for dates tuned to your exact location.

Varieties to grow

8 varieties of onions in the HomeSown library. Tap any for its full grow guide.

Cipollini Onion →Pearl Onion →Red Onion →Spanish Onion →Vidalia Sweet Onion →Walla Walla Sweet Onion →White Onion →Yellow Sweet Onion →

Common problems with onions

What to watch for, with identification and treatment for each

Onion MaggotLeek MothSeed Corn MaggotSeedcorn MaggotBulb MiteWirewormsPink RootBotrytis Neck RotFusarium Basal RotWhite RotCracking & SplittingBulb Rot

🌱 Grow onions with a calendar built for your exact yard

HomeSown turns your ZIP code into a personalized planting calendar, watering reminders, and pest help. Free to start.

Start your free garden →

onions — full zone guide

All zonesZone 5 →Zone 6 →Zone 7 →Zone 8 →Zone 9 →Zone 10 →