When to plant broccoli in San Antonio

How to grow Broccoli San Antonio climate

Where are you growing?

Tight fit

Not realistic in greenhouse

Not realistic in a cold frame

Broccoli in San Antonio is doable with planning outdoors. 73 suitable days are enough for fast varieties (55 days) but not slow ones (75 days).

Start indoors: December 5 – January 29
Transplant outside: January 23 – March 19
Harvest: March 19 – June 2
Season vs crop: 73 grow days vs 55–75 needed
Typical frost (last spring – first fall): February 11 – January 7

Broccoli in San Antonio is doable with planning outdoors. 73 suitable days are enough for fast varieties (55 days) but not slow ones (75 days).

Start seeds indoors December 5 – January 29, then transplant January 23 – March 19 so the crop can finish outdoors.

Planting conditions

Start indoors
Harden off
Transplant outside
Grow outdoors
Harvest

Local activity windows for this place and growing method. Dashed lines are typical last and first frost.

Suitable growing days in a row73

Days to harvest55–75 days from transplant

Dec 5 – Jan 29

Start indoors

Jan 16 – Jan 22

Harden off

January 23

Transplant outside

Jan 24 – Mar 18

Grow outdoors

Mar 19 – Jun 2

Harvest

Activity	Window	Notes
Start indoors	Dec 5 – Jan 29	Sow indoors before the outdoor window.
Harden off	Jan 16 – Jan 22	Acclimate seedlings outdoors before planting.
Transplant outside	January 23	Move plants outside on this day (start of the plant-out window).
Grow outdoors	Jan 24 – Mar 18	Plants grow outdoors until harvest.
Harvest	Mar 19 – Jun 2	Expected harvest from typical days to harvest.

Based on average frost dates. 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 (59 – 75 °F) and tolerable (39 – 81 °F) ranges.

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 startDecember 5

Latest indoor seed startJanuary 29

Transplant outdoorsJanuary 23 – March 19

Direct sow windownot recommended here

Suitable growing windowJanuary 23 – April 5 (73 days)

Expected harvestMarch 19 – June 2

How these dates are judged

Ideal conditions: Daytime air from 59 – 75 °F.
Suitable conditions: Daytime air from 39 – 81 °F.
Last frost and first frost: Typical spring and fall frost dates for San Antonio, shown in the key dates.
Days to harvest: 55–75 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 Broccoli: Jan 23 – Apr 5 (73 days)

Planting window for Broccoli: Jan 23 – Mar 19 (56 days)

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.

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 4 · Jan 19 – Jan 25

Average 43 to 60 °F · Possible 24 to 77 °F

Growing: tolerable

Planting: not sowable

A week is in range when its average low and high sit inside the tolerance band 39 to 81 °F; it is suitable when that average range also overlaps the ideal 59 to 75 °F band and possible readings stay within 39 °F to 81 °F. Crossing a possible limit, or missing the ideal band, makes it tolerable; a possible low below 39 °F makes it tolerable. 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 Broccoli 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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