When to plant kohlrabi in Columbus, Ohio

March 23 – April 6

Transplant outdoors · typical Columbus year

Climate basis: NOAA station Columbus Wcmh, OH (USC00331785), 4 mi (7 km) from downtown Columbus (ZCTA 43215 centroid), elevation 740 ft, on the 1991–2020 climate normals. Transplant kohlrabi outdoors from approximately the dates above, anchored to the median last spring 32°F freeze (April 20). One year in ten still freezes after May 7.

Last spring freezeApril 201-in-10 after May 7

First fall freezeOctober 241-in-10 before Oct 13

Frost-free season≈ 185 daysmedian at 32°F

Hard freeze, 28°Apr 8 – Nov 3kills even hardy greens

USDA zone6b-5 to 0°F winter low — not frost timing

The Columbus year

Start seeds indoorsFeb 9 – Feb 23

Transplant outdoorsMar 23 – Apr 6

Fall plantingAug 29 – Sep 26

indoors under lights
in the garden
frost-free season
1-in-10 years still freeze to May 7

Kohlrabi in Columbus · freeze context from Columbus Wcmh, OH, 1991–2020 normals.

Every method, with its sources

Start seeds indoors

Feb 9 – Feb 23

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 (Apr 20). University of New Hampshire Extension

Transplant outdoors

Mar 23 – Apr 6

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 (Apr 20). University of New Hampshire Extension · Purdue University Extension

Fall planting

Aug 29 – Sep 26

Purdue Table 2: plant fall kohlrabi at least 4–8 weeks before the first fall frost. Anchored to the median first fall freeze (Oct 24). 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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