When to plant onions in Maine

Plant out in Portland

Mar 15–Apr 5

Across Maine the window opens between March 14 and April 4. Find your city below; the dates follow each town's own average last frost.

Start indoors, Portland: Feb 1–Mar 1
Plant out, Portland: Mar 15–Apr 5
Last frost, Portland: Apr 26

Start seeds indoors 8–12 weeks before the last frost; plant out 3–6 weeks before the last frost. Northern gardens need long-day varieties and southern gardens need short-day ones. A wrong pick gives small bulbs.

Onions planting dates by city

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost

JanFebMarAprMayJunJulAugSepOctNovDec

PortlandMar 15–Apr 5

LewistonMar 14–Apr 4

BangorMar 23–Apr 13

South PortlandMar 15–Apr 5

AuburnMar 14–Apr 4

SanfordApr 4–Apr 25

BiddefordMar 28–Apr 18

WestbrookMar 15–Apr 5

SacoMar 15–Apr 5

Questions

When should I plant onions in Maine?

In Portland, plant out from March 15 to April 5. Across Maine the window opens between March 14 and April 4, depending on the local last frost.

How is this date worked out?

Start seeds indoors 8–12 weeks before the last frost; plant out 3–6 weeks before the last frost. Frost dates are NOAA 1991–2020 averages for the weather station nearest each city.

More for Maine

Onions in other states

Frost dates for every city in Maine