When should I plant tomatoes in ZIP 90012?

In ZIP 90012, the main tomatoes target is around Jan 27, based on the representative Los Angeles frost station and USDA zone 10b.

When should I start tomatoes seeds indoors in 90012?

Start tomatoes seeds indoors in ZIP 90012 around Dec 9, about 42 days before the Jan 20 last-frost estimate.

Is this a guaranteed planting date?

No. GrowZone uses frost-date estimates, hardiness zones, and crop timing rules for planning. Local microclimates and current weather can shift the right date.

ZIP 90012 planting calendar

When to plant tomatoes in Los Angeles, CA - Zone 10b

Q: When is the first frost in Los Angeles?

Los Angeles (ZIP 90012) has an average first fall frost around Dec 15, leaving about 329 frost-free days.

In ZIP 90012, plant tomatoes around Jan 27; this uses the Los Angeles frost station, USDA zone 10b, and tomatoes timing rules.

Your Los Angeles calendar has a 329-day estimated frost-free season. This estimate uses the representative Los Angeles frost station, USDA zone 10b, and tomatoes timing rules.

Source: los-angeles-civic-center frost station, USDA zone 10b, last updated 2026-06-28. Verify locally before planting high-value crops because microclimates, current weather, and yard exposure can move the safe date.

USDA zone 10b Los Angeles frost station University of California Agriculture and Natural Resources Updated 2026-06-28

Read the method

Answer first

When to start tomatoes seeds indoors in Los Angeles

In ZIP 90012, start tomatoes seeds indoors around Dec 9, about 42 days before the Jan 20 last-frost estimate.

Start tomatoes seeds indoors in Los Angeles around Dec 9, about 42 days before the Jan 20 last-frost estimate.

Seed starting schedule

Tomatoes dates for Los Angeles, CA

Step	Date	How to use it
Start Indoors	December 9, 2025	Start seeds under lights or in a bright indoor seed-starting space.
Transplant Outdoors	January 27, 2026	Move hardened-off seedlings outside after the frost-risk window.

Last frost

When is the last frost in Los Angeles?

Los Angeles (ZIP 90012) has an average last spring frost around Jan 20.

First frost

When is the first frost in Los Angeles?

The average first fall frost is around Dec 15, giving about 329 frost-free days.

Season map

Tomatoes windows by month

JanFebMarAprMayJunJulAugSepOctNovDec

Start indoors

Dec 9

Transplant

Jan 27

Harvest

Apr 15

Frost watch

Sep 28

Reminder workflow

Every date has a next action

Start tomatoes indoorsDec 9

Last frost windowJan 20

Transplant tomatoesJan 27

First tomatoes harvest windowApr 15

Last tomatoes sowing targetSep 28

Signal	Value	Why it matters
Last frost estimate	January 20, 2026	Warm-season transplant risk starts falling after this window.
First frost estimate	December 15, 2026	Fall planting counts backward from this date.
Season length	329 days	Longer seasons can support succession crops.
Spacing	18-24 in	Airflow and root space affect yield.
Soil temperature	60 F+	Seeds and transplants stall in cold soil.

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Local data

Why this date changes by ZIP

Los Angeles frost history and USDA zone 10b shift the safe planting window. GrowZone uses a local representative station instead of one national rule.

University of California Agriculture and Natural Resources is the kind of local source to verify against when a crop is expensive, weather is unusual, or your yard has a cold pocket.

Crop note

Tomatoes timing notes

Harden seedlings off for a week before transplanting. Tomatoes prefers full sun, 18-24 in spacing, and soil near 60 F+.

For fall, count backward from Dec 15. A conservative last sowing target is around Sep 28.