When to plant onions in Pennsylvania

Plant out in Philadelphia

Feb 16–Mar 9

Across Pennsylvania the window opens between February 16 and March 19. Find your city below; the dates follow each town's own average last frost.

Start indoors, Philadelphia: Jan 5–Feb 2
Plant out, Philadelphia: Feb 16–Mar 9
Last frost, Philadelphia: Mar 30

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

PhiladelphiaFeb 16–Mar 9

PittsburghMar 7–Mar 28

AllentownMar 9–Mar 30

ReadingMar 3–Mar 24

ErieMar 15–Apr 5

BethlehemMar 9–Mar 30

ScrantonMar 12–Apr 2

LancasterMar 8–Mar 29

LevittownMar 10–Mar 31

HarrisburgMar 4–Mar 25

YorkMar 15–Apr 5

Wilkes-BarreMar 12–Apr 2

AltoonaMar 14–Apr 4

State CollegeMar 9–Mar 30

Penn HillsMar 5–Mar 26

NorristownFeb 25–Mar 18

ChesterFeb 16–Mar 9

Mount LebanonMar 7–Mar 28

Bethel ParkMar 7–Mar 28

EastonMar 7–Mar 28

HazletonMar 19–Apr 9

Drexel HillFeb 19–Mar 12

MonroevilleMar 11–Apr 1

WilliamsportMar 14–Apr 4

LebanonMar 9–Mar 30

PlumMar 5–Mar 26

King of PrussiaFeb 25–Mar 18

ChambersburgMar 7–Mar 28

PottstownMar 9–Mar 30

CarlisleMar 12–Apr 2

All 35 cities

City	Start indoors	Plant out	Last frost
Philadelphia	Jan 5 to Feb 2	Feb 16 to Mar 9	Mar 30
Pittsburgh	Jan 24 to Feb 21	Mar 7 to Mar 28	Apr 18
Allentown	Jan 26 to Feb 23	Mar 9 to Mar 30	Apr 20
Reading	Jan 20 to Feb 17	Mar 3 to Mar 24	Apr 14
Erie	Feb 1 to Mar 1	Mar 15 to Apr 5	Apr 26
Bethlehem	Jan 26 to Feb 23	Mar 9 to Mar 30	Apr 20
Scranton	Jan 29 to Feb 26	Mar 12 to Apr 2	Apr 23
Lancaster	Jan 25 to Feb 22	Mar 8 to Mar 29	Apr 19
Levittown	Jan 27 to Feb 24	Mar 10 to Mar 31	Apr 21
Harrisburg	Jan 21 to Feb 18	Mar 4 to Mar 25	Apr 15
York	Feb 1 to Mar 1	Mar 15 to Apr 5	Apr 26
Wilkes-Barre	Jan 29 to Feb 26	Mar 12 to Apr 2	Apr 23
Altoona	Jan 31 to Feb 28	Mar 14 to Apr 4	Apr 25
State College	Jan 26 to Feb 23	Mar 9 to Mar 30	Apr 20
Penn Hills	Jan 22 to Feb 19	Mar 5 to Mar 26	Apr 16
Norristown	Jan 14 to Feb 11	Feb 25 to Mar 18	Apr 8
Chester	Jan 5 to Feb 2	Feb 16 to Mar 9	Mar 30
Mount Lebanon	Jan 24 to Feb 21	Mar 7 to Mar 28	Apr 18
Bethel Park	Jan 24 to Feb 21	Mar 7 to Mar 28	Apr 18
Easton	Jan 24 to Feb 21	Mar 7 to Mar 28	Apr 18
Hazleton	Feb 5 to Mar 5	Mar 19 to Apr 9	Apr 30
Drexel Hill	Jan 8 to Feb 5	Feb 19 to Mar 12	Apr 2
Monroeville	Jan 28 to Feb 25	Mar 11 to Apr 1	Apr 22
Williamsport	Jan 31 to Feb 28	Mar 14 to Apr 4	Apr 25
Lebanon	Jan 26 to Feb 23	Mar 9 to Mar 30	Apr 20
Plum	Jan 22 to Feb 19	Mar 5 to Mar 26	Apr 16
King of Prussia	Jan 14 to Feb 11	Feb 25 to Mar 18	Apr 8
Chambersburg	Jan 24 to Feb 21	Mar 7 to Mar 28	Apr 18
Pottstown	Jan 26 to Feb 23	Mar 9 to Mar 30	Apr 20
Carlisle	Jan 29 to Feb 26	Mar 12 to Apr 2	Apr 23
Allison Park	Jan 22 to Feb 19	Mar 5 to Mar 26	Apr 16
New Castle	Feb 5 to Mar 5	Mar 19 to Apr 9	Apr 30
Murrysville	Jan 28 to Feb 25	Mar 11 to Apr 1	Apr 22
Baldwin	Jan 24 to Feb 21	Mar 7 to Mar 28	Apr 18
Phoenixville	Jan 24 to Feb 21	Mar 7 to Mar 28	Apr 18

Questions

When should I plant onions in Pennsylvania?

In Philadelphia, plant out from February 16 to March 9. Across Pennsylvania the window opens between February 16 and March 19, 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 Pennsylvania

Onions in other states

Frost dates for every city in Pennsylvania