When to plant leeks in Columbus, Ohio
March 23 – April 6
Transplant outdoors · typical Columbus yearClimate 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 leeks 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.
The Columbus year
- indoors under lights
- in the garden
- frost-free season
- 1-in-10 years still freeze to May 7
Every method, with its sources
Start seeds indoors
Jan 12 – Jan 26Sow 8–10 weeks before the set-out window opens (UNH: time from seed to transplant 8–10 weeks). Anchored to the median last spring freeze (Apr 20). University of New Hampshire Extension
Transplant outdoors
Mar 23 – Apr 6UNH: 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
Direct-sow outdoors
Not calculatedLeeks are typically transplanted (Purdue marks leek 'typically transplanted'); the cited guides do not time direct sowing.
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.
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.