FrostCal

When to Plant Onions in Michigan

In a typical Michigan location, start seeds indoors Feb 19 – Mar 5, then transplant outdoors Apr 2 – Apr 16. Across the state, the outdoor planting window starts as early as Mar 22 in Port Huron and as late as Apr 21 in Cadillac.

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
DetroitFeb 10 – Feb 24Mar 24 – Apr 7
Grand RapidsFeb 25 – Mar 11Apr 8 – Apr 22
WarrenFeb 10 – Feb 24Mar 24 – Apr 7
Sterling HeightsFeb 19 – Mar 5Apr 2 – Apr 16
Ann ArborFeb 24 – Mar 10Apr 7 – Apr 21
LansingFeb 20 – Mar 6Apr 3 – Apr 17
Clinton TownshipFeb 19 – Mar 5Apr 2 – Apr 16
FlintFeb 25 – Mar 11Apr 8 – Apr 22
DearbornFeb 16 – Mar 2Mar 30 – Apr 13
LivoniaFeb 20 – Mar 6Apr 3 – Apr 17
CantonFeb 13 – Feb 27Mar 27 – Apr 10
TroyFeb 15 – Mar 1Mar 29 – Apr 12
WestlandFeb 9 – Feb 23Mar 23 – Apr 6
Farmington HillsFeb 20 – Mar 6Apr 3 – Apr 17
KalamazooFeb 17 – Mar 3Mar 31 – Apr 14
WaterfordFeb 18 – Mar 4Apr 1 – Apr 15
WyomingFeb 25 – Mar 11Apr 8 – Apr 22
ShelbyFeb 15 – Mar 1Mar 29 – Apr 12
Rochester HillsFeb 15 – Mar 1Mar 29 – Apr 12
SouthfieldFeb 20 – Mar 6Apr 3 – Apr 17
West Bloomfield TownshipFeb 18 – Mar 4Apr 1 – Apr 15
TaylorFeb 9 – Feb 23Mar 23 – Apr 6
PontiacFeb 15 – Mar 1Mar 29 – Apr 12
Saint Clair ShoresFeb 18 – Mar 4Apr 1 – Apr 15
Royal OakFeb 10 – Feb 24Mar 24 – Apr 7
NoviFeb 20 – Mar 6Apr 3 – Apr 17
Dearborn HeightsFeb 20 – Mar 6Apr 3 – Apr 17
Battle CreekFeb 19 – Mar 5Apr 2 – Apr 16
KentwoodFeb 25 – Mar 11Apr 8 – Apr 22
RedfordFeb 20 – Mar 6Apr 3 – Apr 17

Showing the 30 most populous of 120 Michigan cities. Dates are estimates from each city's NOAA frost normals and university extension timing guidelines. See all Michigan cities.

Frequently Asked Questions

When should I plant onions in Michigan?

In a typical Michigan location, start seeds indoors Feb 19 – Mar 5, then transplant outdoors Apr 2 – Apr 16. Across the state, the outdoor planting window starts as early as Mar 22 in Port Huron and as late as Apr 21 in Cadillac.

When is the last frost in Michigan?

The average last spring frost in Michigan ranges from April 19 in Port Huron to May 19 in Cadillac, 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 Michigan

When to plant onions in other states

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