FrostCal

When to Plant Onions in Utah

In a typical Utah location, start seeds indoors Feb 13 – Feb 27, then transplant outdoors Mar 27 – Apr 10. Across the state, the outdoor planting window starts as early as Feb 14 in Saint George and as late as May 7 in Heber City.

Method Start indoors, then transplant
Days to maturity 90–120 days

Start seeds indoors 8-10 weeks before last frost (or use sets/transplants); set out 2-4 weeks before last frost, very cold-tolerant as seedlings.

Onions Planting Dates by City

CityStart indoorsTransplant
Salt Lake CityJan 20 – Feb 3Mar 3 – Mar 17
West Valley CityJan 28 – Feb 11Mar 11 – Mar 25
ProvoFeb 7 – Feb 21Mar 21 – Apr 4
West JordanFeb 18 – Mar 4Apr 1 – Apr 15
OremFeb 8 – Feb 22Mar 22 – Apr 5
SandyFeb 18 – Mar 4Apr 1 – Apr 15
OgdenFeb 10 – Feb 24Mar 24 – Apr 7
LaytonFeb 8 – Feb 22Mar 22 – Apr 5
Saint GeorgeJan 3 – Jan 17Feb 14 – Feb 28
South JordanFeb 7 – Feb 21Mar 21 – Apr 4
MillcreekFeb 14 – Feb 28Mar 28 – Apr 11
TaylorsvilleJan 20 – Feb 3Mar 3 – Mar 17
LehiFeb 19 – Mar 5Apr 2 – Apr 16
LoganFeb 27 – Mar 13Apr 10 – Apr 24
MurrayFeb 14 – Feb 28Mar 28 – Apr 11
DraperFeb 7 – Feb 21Mar 21 – Apr 4
BountifulFeb 14 – Feb 28Mar 28 – Apr 11
RivertonFeb 7 – Feb 21Mar 21 – Apr 4
Pleasant GroveFeb 6 – Feb 20Mar 20 – Apr 3
RoyFeb 11 – Feb 25Mar 25 – Apr 8
Spanish ForkFeb 14 – Feb 28Mar 28 – Apr 11
KearnsJan 28 – Feb 11Mar 11 – Mar 25
Cottonwood HeightsFeb 18 – Mar 4Apr 1 – Apr 15
TooeleFeb 21 – Mar 7Apr 4 – Apr 18
MidvaleFeb 18 – Mar 4Apr 1 – Apr 15
SpringvilleFeb 14 – Feb 28Mar 28 – Apr 11
HolladayFeb 18 – Mar 4Apr 1 – Apr 15
HerrimanFeb 7 – Feb 21Mar 21 – Apr 4
ClearfieldFeb 18 – Mar 4Apr 1 – Apr 15
KaysvilleFeb 8 – Feb 22Mar 22 – Apr 5

Showing the 30 most populous of 67 Utah cities. Dates are estimates from each city's NOAA frost normals and university extension timing guidelines. See all Utah cities.

Frequently Asked Questions

When should I plant onions in Utah?

In a typical Utah location, start seeds indoors Feb 13 – Feb 27, then transplant outdoors Mar 27 – Apr 10. Across the state, the outdoor planting window starts as early as Feb 14 in Saint George and as late as May 7 in Heber City.

When is the last frost in Utah?

The average last spring frost in Utah ranges from March 14 in Saint George to June 4 in Heber City, based on NOAA 1991–2020 climate normals.

How long do onions take to grow?

Onions typically take 90–120 days from planting to harvest. Start seeds indoors 8-10 weeks before last frost (or use sets/transplants); set out 2-4 weeks before last frost, very cold-tolerant as seedlings.

Other Crops in Utah

When to plant onions in other states

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