California planting calendar

When to plant spinach in California — sow, transplant & harvest dates

California is mostly USDA zone 9b (range 5a-11a). Dates below are derived from spinach's frost tolerance and California's frost window — not generic national averages.

Spinach planting timetable for California

Stage	When in California	Anchor
Direct-sow / set out (main)	October — February	Grown through the cool season, not summer
Shoulder sowing	September and again late February	Avoid germinating into summer heat
First harvest	~45 days after sowing (late autumn through spring)	45-day crop

Dates are state-wide averages for the dominant zone. Local microclimates — elevation, urban heat, coastal moderation — can shift the window by 1-2 weeks. Use the frost-date calculator for a date tuned to your town.

Why California's climate shifts the spinach dates

California flips the calendar: its winter is the productive spinach season while northern states are frozen, and its summer is the off-season. California packs more climate diversity than almost any state — alpine mountains, Mediterranean coast, Central Valley farmland, and desert. Coastal and valley areas grow year-round.

Spinach is direct-sown only — it does not transplant well and runs to seed quickly under any stress. Sow as soon as soil can be worked, 4–6 weeks before the last spring frost; it germinates in soil as cold as 4 °C and seedlings survive light freezes to -6 °C. Bolt risk rises sharply once daytime temperatures consistently exceed 24 °C or day length passes 14 hours, so succession-sow every 2 weeks and switch to heat-tolerant varieties in late spring. In Zones 7–10, a second sowing in late summer or early fall produces the best crop of the year.

Frost-risk note

Light frost in the high Sierra Nevada (zone 5a-6a) only nips the outer leaves — heat, not cold, ends the crop.

Regional variation within California

the southern coast and Imperial Valley (zone 11a) can sow earliest in autumn and latest into late winter; the high Sierra Nevada (zone 5a-6a) has a slightly shorter, frost-bracketed window.

Los Angeles — USDA zone 10b
San Francisco — USDA zone 10b
Sacramento — USDA zone 9b
San Diego — USDA zone 10b
Fresno — USDA zone 9b

What else to plant in California around then

The same cool window suits other greens, brassicas, peas, carrots, and radishes — fill beds October through February.

Quick-grow guide

Sun: Full sun to partial shade.
Soil temperature for germination: 4-21 °C (40-70 °F).
Spacing: 3-6 inches (8-15 cm) between plants.
Days to harvest: ~45 days from planting out.

Frequently asked questions

When is the best time to plant spinach in California?

In California (mostly USDA zone 9b), grow spinach as a cool-season crop: direct-sow from October through February, harvest ~45 days later, and skip summer entirely — heat above 24 °C bolts it. Spinach are cold-hardy — they tolerate frost and actively prefer cool weather, so they go in well before the last spring frost and bolt in summer heat.

What USDA zone is California?

Most of California sits in USDA hardiness zone 9b, with the state spanning roughly 5a-11a from the high Sierra Nevada (zone 5a-6a) to the southern coast and Imperial Valley (zone 11a). The last spring frost averages mid-February (coast) to late April (interior) and the first fall frost mid-November (coast) to mid-October (interior).

Can you grow spinach in California?

Yes. California's dominant zone 9b supports spinach — the key is timing. Spinach are cold-hardy — they tolerate frost and actively prefer cool weather, so they go in well before the last spring frost and bolt in summer heat.

Does the planting date change across California?

the southern coast and Imperial Valley (zone 11a) can sow earliest in autumn and latest into late winter; the high Sierra Nevada (zone 5a-6a) has a slightly shorter, frost-bracketed window.

What else can I plant in California around the same time?

The same cool window suits other greens, brassicas, peas, carrots, and radishes — fill beds October through February.

Source and methodology

State zone spans from the USDA Plant Hardiness Zone Map (2023); frost-date averages from NOAA Climate Data Online. Hot-state two-season timing cross-checked against the UF/IFAS Florida Gardening Calendar and the University of Arizona Cooperative Extension planting calendar. Curated by the Growli editorial team.