When to Plant Onions in Zone 10
In USDA zone 10a, start seeds indoors around November 21, transplant or plant outdoors January 2 to April 22, and expect your first harvest around April 22. (10a shown here — see 10a and 10b dates separately below.)
Onions planting calendar for USDA Zone 10a
Average last spring frost
January 30
Average first fall frost
December 30
Start seeds indoors
Nov 21
Transplant outdoors
Jan 2
Projected first harvest
Apr 22
Most onions mature in about 90 to 110 days depending on the variety, needing roughly 334 frost-free days in zone 10a.
Onions planting calendar for USDA Zone 10b
Average last spring frost
January 30
Average first fall frost
December 30
Start seeds indoors
Nov 21
Transplant outdoors
Jan 2
Projected first harvest
Apr 22
Most onions mature in about 90 to 110 days depending on the variety, needing roughly 334 frost-free days in zone 10b.
Not sure whether you're in 10a or 10b? 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.
Common problems with onions
What to watch for, with identification and treatment for each
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