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ZIP 90012 planting calendar

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

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.

Reviewed by GrowZone Editorial. Calculated from the los-angeles-civic-center frost station and USDA zone 10b, last updated 2026-06-28.

In the Los Angeles area, gardeners usually wait until Jan 27 to set tomato transplants out because cold snaps near Jan 20 can still matter.

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

StepDateHow to use it
Start IndoorsDecember 9, 2025Start seeds under lights or in a bright indoor seed-starting space.
Transplant OutdoorsJanuary 27, 2026Move 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
SignalValueWhy it matters
Last frost estimateJanuary 20, 2026Warm-season transplant risk starts falling after this window.
First frost estimateDecember 15, 2026Fall planting counts backward from this date.
Season length329 daysLonger seasons can support succession crops.
Spacing18-24 inAirflow and root space affect yield.
Soil temperature60 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.