When to plant sweet marjoram in Columbus, Ohio
April 20 – May 4
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 sweet marjoram 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
Feb 23 – Mar 9NC State's Extension Gardener Plant Toolbox starts marjoram seed indoors about 6 to 8 weeks before the last spring frost date, and Clemson HGIC gives the identical 6-to-8-week lead, so the two sources agree. Anchored to the median last spring freeze (Apr 20). NC State Extension, North Carolina Extension Gardener Plant Toolbox · Clemson University Cooperative Extension, Home & Garden Information Center
Transplant outdoors
Apr 20 – May 4Clemson HGIC sets marjoram transplants out after the last killing frost and UMD Extension names marjoram among herbs planted outside after the danger of frost has passed; both agree, so the window opens at the last spring freeze. Anchored to the median last spring freeze (Apr 20). Clemson University Cooperative Extension, Home & Garden Information Center
Direct-sow outdoors
Apr 6 – Apr 20NC State's Extension Gardener Plant Toolbox gives a point rule — sow seed directly outdoors about two weeks before the last spring frost date — which opens a two-week sowing span ending at the last freeze; note the transplant window for this tender herb is later. Anchored to the median last spring freeze (Apr 20). NC State Extension, North Carolina Extension Gardener Plant Toolbox
Variety assumption: Grown as an annual across most of the US; NC State's plant toolbox treats it as a tender perennial that is replaced each year in cold climates.
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)
- NC State Extension, North Carolina Extension Gardener Plant Toolbox: Origanum majorana (Knotted Marjoram, Marjoram, Pot Marjoram, Sweet Marjoram) (accessed 2026-07-25)"To plant from seed, start seeds indoors about 6 to 8 weeks prior to the last spring frost date."
- Clemson University Cooperative Extension, Home & Garden Information Center: Herbs (accessed 2026-07-25)"Start seed indoors 6 to 8 weeks before planting or set transplants out after the last killing frost."