FrostCal

When to Plant Onions in Maryland

In a typical Maryland location, start seeds indoors Jan 23 – Feb 6, then transplant outdoors Mar 6 – Mar 20. Across the state, the outdoor planting window starts as early as Feb 22 in California and as late as Mar 27 in Westminster.

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
BaltimoreJan 13 – Jan 27Feb 24 – Mar 10
ColumbiaJan 30 – Feb 13Mar 13 – Mar 27
GermantownFeb 3 – Feb 17Mar 17 – Mar 31
Silver SpringJan 30 – Feb 13Mar 13 – Mar 27
FrederickJan 22 – Feb 5Mar 5 – Mar 19
WaldorfJan 23 – Feb 6Mar 6 – Mar 20
Glen BurnieJan 30 – Feb 13Mar 13 – Mar 27
GaithersburgJan 21 – Feb 4Mar 4 – Mar 18
RockvilleJan 21 – Feb 4Mar 4 – Mar 18
Ellicott CityJan 30 – Feb 13Mar 13 – Mar 27
DundalkJan 13 – Jan 27Feb 24 – Mar 10
BethesdaJan 29 – Feb 12Mar 12 – Mar 26
BowieFeb 11 – Feb 25Mar 25 – Apr 8
TowsonJan 22 – Feb 5Mar 5 – Mar 19
Aspen HillJan 21 – Feb 4Mar 4 – Mar 18
WheatonJan 21 – Feb 4Mar 4 – Mar 18
Bel Air SouthJan 30 – Feb 13Mar 13 – Mar 27
Gwynn OakJan 22 – Feb 5Mar 5 – Mar 19
PotomacJan 21 – Feb 4Mar 4 – Mar 18
SevernJan 30 – Feb 13Mar 13 – Mar 27
North BethesdaJan 21 – Feb 4Mar 4 – Mar 18
CatonsvilleJan 13 – Jan 27Feb 24 – Mar 10
AnnapolisJan 16 – Jan 30Feb 27 – Mar 13
HagerstownJan 31 – Feb 14Mar 14 – Mar 28
EssexJan 13 – Jan 27Feb 24 – Mar 10
HanoverJan 30 – Feb 13Mar 13 – Mar 27
WoodlawnJan 22 – Feb 5Mar 5 – Mar 19
Severna ParkJan 16 – Jan 30Feb 27 – Mar 13
OdentonJan 30 – Feb 13Mar 13 – Mar 27
Saint CharlesJan 23 – Feb 6Mar 6 – Mar 20

Showing the 30 most populous of 151 Maryland cities. Dates are estimates from each city's NOAA frost normals and university extension timing guidelines. See all Maryland cities.

Frequently Asked Questions

When should I plant onions in Maryland?

In a typical Maryland location, start seeds indoors Jan 23 – Feb 6, then transplant outdoors Mar 6 – Mar 20. Across the state, the outdoor planting window starts as early as Feb 22 in California and as late as Mar 27 in Westminster.

When is the last frost in Maryland?

The average last spring frost in Maryland ranges from March 22 in California to April 24 in Westminster, 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 Maryland

When to plant onions in other states

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