When to plant onions in Delaware

Plant out in Wilmington

Feb 24–Mar 17

Across Delaware the window opens between February 21 and February 24. Find your city below; the dates follow each town's own average last frost.

Start indoors, Wilmington: Jan 13–Feb 10
Plant out, Wilmington: Feb 24–Mar 17
Last frost, Wilmington: Apr 7

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

WilmingtonFeb 24–Mar 17

DoverFeb 21–Mar 14

NewarkFeb 24–Mar 17

MiddletownFeb 24–Mar 17

BearFeb 24–Mar 17

Questions

When should I plant onions in Delaware?

In Wilmington, plant out from February 24 to March 17. Across Delaware the window opens between February 21 and February 24, 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 Delaware

Onions in other states

Frost dates for every city in Delaware