Spinach in Zone 10a & 10b

Spinacia oleracea

When to plant spinach in zone 10b

Zones 10a and 10b share the same average frost dates in our data, so this page covers both.

Method: Start indoors: Start indoors from seed, then transplant outside. In your zone, Spinach needs a head start on the heat that direct-sowing elsewhere doesn't require.

Window	Fall window
Start indoors	Aug–Dec
Direct sow / transplant outside	Sep–Jan
Estimated harvest	Oct 11–Mar 12 '27 (~40 days after transplanting)

Spacing: 9 per square foot (square-foot-gardening spacing). Mature height: 0.5-1 ft.

Zone 10b dates sourced from growinginthegarden.com.

Spinach is one of the fastest, most cold-tolerant greens you can grow, direct-seeded a full month before your last frost, but it's also quick to bolt once the weather warms, so the growing window is short and worth planning around rather than fighting.

How spinach fits zone 10's season

Zone 10b's frost-free window runs about 324 days, from January 30 to December 20. Spinach needs about 40 days from sowing to first harvest.

Good companions

Radish: Radish breaks up soil and matures quickly alongside spinach.

Where to buy spinach seeds

See why we recommend these suppliers →

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