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When to plant tomato in San Antonio

How to grow TomatoSan Antonio climate
Where are you growing?

Comfortable

Not realistic in greenhouse

Comfortable in a cold frame

Tomato in San Antonio is a good fit outdoors. The suitable growing window of 122 days covers the 55–90 days this plant usually needs.

Start indoors
January 19 – March 15
Transplant outside
March 20 – May 14
Harvest
May 14 – August 12
Season vs crop
122 grow days vs 55–90 needed
Typical frost (last spring – first fall)
February 11 – January 7

Tomato in San Antonio is a good fit outdoors. The suitable growing window of 122 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~Feb 11~Jan 7
  • 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. Dashed lines are typical last and first frost.
Suitable growing days in a row122
Days to harvest55–90 days from transplant
Jan 19 – Mar 15
Start indoors
Mar 13 – Mar 19
Harden off
March 20
Transplant outside
Mar 21 – May 13
Grow outdoors
May 14 – Aug 12
Harvest
ActivityWindowNotes
Start indoorsJan 19 – Mar 15Sow indoors before the outdoor window.
Harden offMar 13 – Mar 19Acclimate seedlings outdoors before planting.
Transplant outsideMarch 20Move plants outside on this day (start of the plant-out window).
Grow outdoorsMar 21 – May 13Plants grow outdoors until harvest.
HarvestMay 14 – Aug 12Expected harvest from typical days to harvest.
Blue fill is usually too cold for this plant. Dashed lines are typical last and first frost. 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 AntonioJANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDECPlantingGrowing
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

Typical last spring frostFebruary 11
Safer last spring frostMarch 6
Typical first fall frostJanuary 7
Safer first fall frostDecember 26
Frost-free days329.5
Earliest indoor seed startJanuary 19
Latest indoor seed startMarch 15
Transplant outdoorsMarch 20 – May 14
Direct sow windownot recommended here
Suitable growing windowMarch 20 – July 19 (122 days)
Expected harvestMay 14 – August 12

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 Antonio, 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 20 – Jul 19 (122 days)

Planting window for Tomato: Mar 20 – May 14 (56 days)

Usually too cold: Jan 1 – Mar 1; Nov 23 – Dec 31

Outdoors: weekly temperatures and windows

Temperatures across the year for San Antonio. 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−20 °C−4 °F−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 20 – Jul 19PlantingMar 20 – May 14No 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 12 · Mar 16 – Mar 22

Average 55 to 74 °F · Possible 42 to 89 °F

Growing: too cold

Planting: not sowable

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 Antonio

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 29.42, -98.49, 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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