When to plant kohlrabi in San Antonio, Texas

January 28 – February 11

Transplant outdoors · typical San Antonio year

Climate basis: NOAA station San Antonio Incarnate Word, TX (USC00417947), 3 mi (5 km) from downtown San Antonio (ZCTA 78205 centroid), elevation 700 ft, on the 1991–2020 climate normals. Transplant kohlrabi outdoors from approximately the dates above, anchored to the median last spring 32°F freeze (February 25). One year in ten still freezes after March 19.

Last spring freezeFebruary 251-in-10 after Mar 19

First fall freezeNovember 281-in-10 before Nov 7

Frost-free season≈ 277 daysmedian at 32°F

Hard freeze, 28°Feb 5 – Dec 15kills even hardy greens

USDA zone9a20 to 25°F winter low — not frost timing

The San Antonio year

Start seeds indoorsDec 17 – Dec 31

Transplant outdoorsJan 28 – Feb 11

Fall plantingOct 3 – Oct 31

indoors under lights
in the garden
frost-free season
1-in-10 years still freeze to Mar 19

Kohlrabi in San Antonio · freeze context from San Antonio Incarnate Word, TX, 1991–2020 normals.

Every method, with its sources

Start seeds indoors

Dec 17 – Dec 31

Sow 4–6 weeks before the set-out window opens (UNH: time from seed to transplant 4–6 weeks). Anchored to the median last spring freeze (Feb 25). University of New Hampshire Extension

Transplant outdoors

Jan 28 – Feb 11

UNH: safe to set out 4 weeks before the last frost; Purdue's hardy class allows 4–6 weeks before. The later UNH start is used. Anchored to the median last spring freeze (Feb 25). University of New Hampshire Extension · Purdue University Extension

Fall planting

Oct 3 – Oct 31

Purdue Table 2: plant fall kohlrabi at least 4–8 weeks before the first fall frost. Anchored to the median first fall freeze (Nov 28). Purdue University Extension

These windows describe typical years (1991–2020 climate normals), not this year's forecast. Freezes happen outside them — especially in frost pockets, valleys, and urban edges. Watch the forecast before committing tender plants.

This week, not a typical year:

Crop rule sources (2)

University of New Hampshire Extension: Growing Vegetables: When to Plant Your Vegetable Garden [fact sheet] (accessed 2026-07-24)
Per-crop 'time from seed to transplant' and 'safe to set out in garden' relative to last frost.
Purdue University Extension: Indiana Vegetable Planting Calendar (HO-186-W) (accessed 2026-07-24)
Hardiness classes: hardy = plant 4-6 wk before last spring frost; semi-hardy = 2-4 wk before; tender = after average last frost; very tender = at least 2 wk after. Table 2: fall planting at least 4-8 wk before first fall frost.

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