When to plant onions in Dallas, Texas

February 2 – February 16

Transplant outdoors · typical Dallas year

Climate basis: NOAA station Dallas Love Fld, TX (USW00013960), 5 mi (9 km) from downtown Dallas (ZCTA 75201 centroid), elevation 440 ft, on the 1991–2020 climate normals. Plant onion sets or transplants from approximately the dates above, anchored to the median last spring 32°F freeze (March 2). One year in ten still freezes after March 19.

Last spring freezeMarch 21-in-10 after Mar 19

First fall freezeNovember 291-in-10 before Nov 10

Frost-free season≈ 272 daysmedian at 32°F

Hard freeze, 28°Feb 18 – Dec 12kills even hardy greens

USDA zone8b15 to 20°F winter low — not frost timing

The Dallas year

Start seeds indoorsNov 24 – Dec 8

Transplant outdoorsFeb 2 – Feb 16

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

Onions in Dallas · freeze context from Dallas Love Fld, TX, 1991–2020 normals.

Every method, with its sources

Start seeds indoors

Nov 24 – Dec 8

Sow 8–10 weeks (UNH) to 10–12 weeks (Minnesota) before planting out; derived from the −4-week set-out date using the UNH lead time. Anchored to the median last spring freeze (Mar 2). University of New Hampshire Extension · University of Minnesota Extension

Transplant outdoors

Feb 2 – Feb 16

UNH: set out transplants (or sets) 4 weeks before the last frost; Purdue's hardy class allows 4–6 weeks before. The later UNH point is used, with a 14-day span. Anchored to the median last spring freeze (Mar 2). University of New Hampshire Extension · Purdue University Extension

Variety assumption: Assumes storage-type bulb onions (about 100–115 days from sets; Penn State lists 105).

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 (3)

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.
University of Minnesota Extension: Growing onions (accessed 2026-07-24)
"You can also raise your own transplants by starting seed indoors 10 to 12 weeks before planting outside."
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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