When should I plant tomatoes in ZIP 92101?

In ZIP 92101, the main tomatoes target is around Feb 6, based on the representative San Diego frost station and USDA zone 10b.

When should I start tomatoes seeds indoors in 92101?

Start tomatoes seeds indoors in ZIP 92101 around Dec 19, about 42 days before the Jan 30 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 92101 planting calendar

When to plant tomatoes in San Diego, CA - Zone 10b

Q: When is the first frost in San Diego?

San Diego (ZIP 92101) has an average first fall frost around Dec 15, leaving about 319 frost-free days.

In ZIP 92101, plant tomatoes around Feb 6; this uses the San Diego frost station, USDA zone 10b, and tomatoes timing rules.

Your San Diego calendar has a 319-day estimated frost-free season. This estimate uses the representative San Diego frost station, USDA zone 10b, and tomatoes timing rules.

Source: san-diego-lindbergh 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 San Diego 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 San Diego

In ZIP 92101, start tomatoes seeds indoors around Dec 19, about 42 days before the Jan 30 last-frost estimate.

Start tomatoes seeds indoors in San Diego around Dec 19, about 42 days before the Jan 30 last-frost estimate.

Seed starting schedule

Tomatoes dates for San Diego, CA

Step	Date	How to use it
Start Indoors	December 19, 2025	Start seeds under lights or in a bright indoor seed-starting space.
Transplant Outdoors	February 6, 2026	Move hardened-off seedlings outside after the frost-risk window.

Last frost

When is the last frost in San Diego?

San Diego (ZIP 92101) has an average last spring frost around Jan 30.

First frost

When is the first frost in San Diego?

The average first fall frost is around Dec 15, giving about 319 frost-free days.

Season map

Tomatoes windows by month

JanFebMarAprMayJunJulAugSepOctNovDec

Start indoors

Dec 19

Transplant

Feb 6

Harvest

Apr 25

Frost watch

Sep 28

Reminder workflow

Every date has a next action

Start tomatoes indoorsDec 19

Last frost windowJan 30

Transplant tomatoesFeb 6

First tomatoes harvest windowApr 25

Last tomatoes sowing targetSep 28

Signal	Value	Why it matters
Last frost estimate	January 30, 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	319 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

San Diego 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.