California · zones 7a–10b
When to plant sweet potatoes in California.
Sow or transplant between Feb 20 to Apr 6 in a typical year, keyed to California's median last frost around Jan 14. Dates below are state medians; your ZIP code shifts them by days to weeks.
The 2026 windows
Sweet Potatoes dates for a typical California season.
1 · Start indoors
Jan 9 to Feb 23
About 6 weeks before set-out. Warm spot, real light.
2 · Set out
Feb 20 to Apr 6
Keyed to the ~Jan 14 last frost. Sow 3" deep, 14" apart.
Harvest
~110 days later
~2.5 lb per plant over ~1 weeks.
California spans more than one climate: Zone 10 is the most common zone, but the state runs 7a to 10b. That's why the planner works from your ZIP code's frost dates, not your zone: mountain and coastal gardens in the same state can be three weeks apart.
In California: watch for
The pests that find sweet potatoes here.
With about 334 frost-free days, sweet potato spends longer in the ground here than in most of the country, which widens the window in which sweetpotato weevil can find it. Scout weekly from midseason and act on the first signs.
Sweetpotato weevil
Narrow tunnels through roots, and a bitter taste that survives cooking.
Organic fix: Plant certified slips, rotate the bed, and destroy any vine with a wilting runner.
Wireworms & white grubs
Shallow holes and grooves chewed into the roots, found only at digging time.
Organic fix: Avoid planting into ground that was in sod last year; rotate away from grassy beds.
Clusters on the tender growing tips of new vines.
Organic fix: Hose them off in the morning, or use insecticidal soap.
Black rot
Dry, firm dark patches on the roots, usually found at harvest or in storage, with a sweet fruity smell.
Organic fix: Start from clean slips cut well above the soil line, never save roots from a bad crop, and rotate 3 years.
Your season math: California gives sweet potatoes about 334 frost-free days, and it needs roughly 110 days to a first harvest. It's a one-planting crop, so time that single sowing well.
Planting sweet potatoes in California: questions
When should I plant sweet potatoes in California?+
In a typical California year, sow sweet potatoes or set out transplants between Feb 20 to Apr 6, keyed to the state's median last frost around Jan 14. Your exact dates shift with your ZIP code and microclimate.
When do I start sweet potatoes seeds indoors in California?+
Start seeds inside about 6 weeks before set-out: roughly Jan 9 to Feb 23 for a typical California season.
What USDA zone is California?+
California spans zones 7a–10b, mostly zone 10. But frost dates, not zones, set planting time. The free planner uses your ZIP code's actual frost dates.
How many sweet potatoes plants do I need?+
Depends who you're feeding. The crop page has exact counts per household size, or the free planner does the math for your family in about 60 seconds.