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When to plant tomato in San Diego

How to grow TomatoSan Diego climate
Where are you growing?

Tight fit

Tight fit in greenhouse

Tight fit in a cold frame

Tomato in San Diego is a good fit outdoors. The suitable growing window of 236 days covers the 55–90 days this plant usually needs.

Start indoors
August 2 – September 26
Transplant outside
October 1 – November 25
Harvest
November 25 – February 23
Season vs crop
236 grow days vs 55–90 needed

Tomato in San Diego is a good fit outdoors. The suitable growing window of 236 days covers the 55–90 days this plant usually needs.

Planting conditions

Tomato planting activities across the year: Start indoors, Harden off, Transplant outside, Grow outdoors, HarvestJFMAMJJASOND
  • Start indoors
  • Harden off
  • Transplant outside
  • Grow outdoors
  • Harvest
Local activity windows for this place and growing method. Blue fill is usually too cold for this plant.
Suitable growing days in a row236
Days to harvest55–90 days from transplant
Aug 2 – Sep 26
Start indoors
Sep 24 – Sep 30
Harden off
October 1
Transplant outside
Oct 2 – Nov 24
Grow outdoors
Nov 25 – Feb 23
Harvest
ActivityWindowNotes
Start indoorsAug 2 – Sep 26Sow indoors before the outdoor window.
Harden offSep 24 – Sep 30Acclimate seedlings outdoors before planting.
Transplant outsideOctober 1Move plants outside on this day (start of the plant-out window).
Grow outdoorsOct 2 – Nov 24Plants grow outdoors until harvest.
HarvestNov 25 – Feb 23Expected harvest from typical days to harvest.
Blue fill is usually too cold for this plant. Adjust a week or two for your conditions.

Planting and growing across the year

Planting is the sow / plant-out window. Growing is daytime air versus this plant’s ideal (70 – 84 °F) and tolerable (55 – 95 °F) ranges.

Tomato planting and growing weeks in San DiegoJANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDECPlantingGrowing
Planting uses sow / plant-out rules (frost, soil germination, night, and last-sow): green when plantable, blue diagonal when nights or soil are too cold, amber cross-hatch when too hot, faint for other calendar limits. Growing shows daytime air against this plant’s ideal and tolerable ranges across the year.

Key dates

Frost-free days365
Earliest indoor seed startAugust 2
Latest indoor seed startSeptember 26
Transplant outdoorsOctober 1 – November 25
Direct sow windownot recommended here
Suitable growing windowMarch 15 – November 5 (236 days)
Expected harvestNovember 25 – February 23

How these dates are judged

Ideal conditions
Daytime air from 70 – 84 °F.
Suitable conditions
Daytime air from 55 – 95 °F.
Last frost and first frost
Typical spring and fall frost dates for San Diego, shown in the key dates.
Days to harvest
55–90 days from transplant, from typical days to harvest.
Sowing window
Dated sow and harvest bars use frost dates, soil minima, night limits, and last-sow count-back from typical crop timing. The year strip and weekly chart use the same window: air ratings only colour weeks inside it.

Growing window for Tomato: Mar 15 – Nov 5 (236 days)

Planting window for Tomato: Oct 1 – Nov 25 (56 days)

Usually too cold: Jan 1 – Mar 15

Outdoors: weekly temperatures and windows

Temperatures across the year for San Diego. Shaded bands are this plant’s ideal and tolerable daytime air ranges. Growing is daytime air suitability; Planting is sow / plant-out conditions (same colour language). Window brackets mark each stretch.

JanFebMarAprMayJunJulAugSepOctNovDec−10 °C14 °F0 °C32 °F10 °C50 °F20 °C68 °F30 °C86 °F40 °C104 °FTolerable 13–35 °CTolerable 55–95 °FIdeal 21–29 °CIdeal 70–84 °FWindowGrowingMar 15 – Nov 5PlantingOct 1 – Nov 25No typical frost here. Timing follows heat, not frost.
  • Ideal range
  • Tolerable range
  • Possible min to max
  • Average min to max
  • Suitable
  • Tolerable
  • Too cold
  • Too hot

Selected week · tap a week or use the arrows

Week 11 · Mar 9 – Mar 15

Average 51 to 61 °F · Possible 44 to 69 °F

Growing: too cold

Planting: too cold

A week is in range when its average low and high sit inside the tolerance band 55 to 95 °F; it is suitable when that average range also overlaps the ideal 70 to 84 °F band and possible readings stay within 32 °F to 95 °F. Crossing a possible limit, or missing the ideal band, makes it tolerable; any chance of frost (possible low below 32 °F) makes it too cold. When a sowing window is calculated, weeks outside that window are uncoloured even if air is in range.

Based on average frost dates.

Show all 53 weeks
Cover method weekly charts

Outdoor weekly chart is above. Open a cover chart only if you grow under fleece, a cold frame, or an unheated greenhouse.

Other plants for San Diego

Calculated by Plan & Plant · Method · Data 2019–2026

Frost and suitability dates are typical figures from climate statistics. Microclimates vary; they are not a guarantee.

How we calculated this
  • Data: ERA5-Land via Open-Meteo, cell 32.72, -117.16, years 2019–2026 (not a 30-year climate normal yet).
  • Typical and safer dates: Typical last frost is the date after which half of winters in this sample had no more frost; safer is later in the sample so fewer winters still frosted.
  • Crop rule: Local windows for Tomato from frost dates, temperature ratings, and crop timing rules.
  • Confidence: Provisional — short or thin sample for this place.
  • Full methodology (algorithm 2026-10-season-6).

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