When to plant sweet marjoram in Salt Lake City, Utah

March 31 – April 14

Transplant outdoors · typical Salt Lake City year

Climate basis: NOAA station Salt Lake Triad Ctr, UT (USC00427606), 1 mi (2 km) from downtown Salt Lake City (ZCTA 84111 centroid), elevation 4280 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 (March 31). One year in ten still freezes after April 19.

Last spring freezeMarch 311-in-10 after Apr 19

First fall freezeNovember 81-in-10 before Oct 23

Frost-free season≈ 224 daysmedian at 32°F

Hard freeze, 28°Mar 8 – Nov 18kills even hardy greens

USDA zone7b5 to 10°F winter low — not frost timing

The Salt Lake City year

Start seeds indoorsFeb 3 – Feb 17

Transplant outdoorsMar 31 – Apr 14

Direct-sow outdoorsMar 17 – Mar 31

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

Sweet Marjoram in Salt Lake City · freeze context from Salt Lake Triad Ctr, UT, 1991–2020 normals.

Every method, with its sources

Start seeds indoors

Feb 3 – Feb 17

NC 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 (Mar 31). NC State Extension, North Carolina Extension Gardener Plant Toolbox · Clemson University Cooperative Extension, Home & Garden Information Center

Transplant outdoors

Mar 31 – Apr 14

Clemson 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 (Mar 31). Clemson University Cooperative Extension, Home & Garden Information Center

Direct-sow outdoors

Mar 17 – Mar 31

NC 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 (Mar 31). 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.

This week, not a typical year:

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."

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