When to plant Garlic in Pennsylvania

In spring, from Feb 10 – Mar 10 in Chester to Apr 1 – May 1 in St. Marys.

In fall, from Aug 1 – Oct 1 in Darby to Aug 15 – Oct 1 in Philadelphia.

USDA's earliest safe spring and latest safe fall planting dates, matched to each place's average frost dates.

Garlic planting dates by place in Pennsylvania
PlaceSpringFall
AllentownMar 10 – Apr 1Spring-planted
AltoonaMar 10 – Apr 1Spring-planted
BaldwinMar 10 – Apr 1Spring-planted
BerwickMar 15 – Apr 15Spring-planted
Bethel ParkMar 10 – Apr 1Spring-planted
BethlehemMar 10 – Apr 1Spring-planted
BloomsburgMar 15 – Apr 15Spring-planted
ButlerApr 1 – May 1Spring-planted
CarlisleMar 10 – Apr 1Spring-planted
ChambersburgMar 10 – Apr 1Spring-planted
ChesterFeb 10 – Mar 10Aug 15 – Oct 1
CoatesvilleMar 10 – Apr 1Spring-planted
ColumbiaMar 15 – Apr 15Spring-planted
DarbyFeb 10 – Mar 10Aug 1 – Oct 1
DunmoreMar 10 – Apr 1Spring-planted
EastonMar 10 – Apr 1Spring-planted
ElizabethtownFeb 20 – Mar 20Spring-planted
EmmausMar 10 – Apr 1Spring-planted
EphrataMar 10 – Apr 1Spring-planted
ErieMar 15 – Apr 15Spring-planted
Franklin ParkMar 10 – Apr 1Spring-planted
GreensburgMar 15 – Apr 15Spring-planted
HanoverMar 10 – Apr 1Spring-planted
HarrisburgFeb 20 – Mar 20Spring-planted
HazletonMar 15 – Apr 15Spring-planted
HermitageApr 1 – May 1Spring-planted
IndianaApr 1 – May 1Spring-planted
Jefferson HillsMar 10 – Apr 1Spring-planted
JohnstownMar 15 – Apr 15Spring-planted
KingstonMar 10 – Apr 1Spring-planted
LancasterMar 10 – Apr 1Spring-planted
LansdaleFeb 20 – Mar 20Spring-planted
LansdowneFeb 10 – Mar 10Aug 1 – Oct 1
LebanonMar 10 – Apr 1Spring-planted
Lower BurrellMar 10 – Apr 1Spring-planted
McKeesportMar 15 – Apr 15Spring-planted
MeadvilleMar 15 – Apr 15Spring-planted
MechanicsburgFeb 20 – Mar 20Spring-planted
MonroevilleMar 10 – Apr 1Spring-planted
MunhallFeb 20 – Mar 20Aug 1 – Oct 1
MurrysvilleMar 10 – Apr 1Spring-planted
NanticokeApr 1 – May 1Spring-planted
New CastleMar 15 – Apr 15Spring-planted
New KensingtonMar 10 – Apr 1Spring-planted
NorristownFeb 20 – Mar 20Spring-planted
NorthamptonMar 10 – Apr 1Spring-planted
PhiladelphiaFeb 10 – Mar 10Aug 15 – Oct 1
PhoenixvilleMar 10 – Apr 1Spring-planted
PittsburghMar 10 – Apr 1Spring-planted
PlumMar 10 – Apr 1Spring-planted
PottstownMar 10 – Apr 1Spring-planted
PottsvilleMar 15 – Apr 15Spring-planted
ReadingFeb 20 – Mar 20Spring-planted
ScrantonMar 10 – Apr 1Spring-planted
SharonMar 15 – Apr 15Spring-planted
St. MarysApr 1 – May 1Spring-planted
State CollegeMar 10 – Apr 1Spring-planted
WashingtonMar 10 – Apr 1Spring-planted
WaynesboroMar 10 – Apr 1Spring-planted
West ChesterMar 15 – Apr 15Spring-planted
West MifflinMar 10 – Apr 1Spring-planted
WhitehallMar 10 – Apr 1Spring-planted
Wilkes-BarreMar 10 – Apr 1Spring-planted
WilkinsburgFeb 20 – Mar 20Aug 1 – Oct 1
WilliamsportMar 10 – Apr 1Spring-planted
WyomissingFeb 20 – Mar 20Spring-planted
YeadonFeb 10 – Mar 10Aug 1 – Oct 1
YorkMar 15 – Apr 15Spring-planted

Planting dates: USDA Home and Garden Bulletin No. 9 (1967), tables 4 and 5. Frost dates: NOAA U.S. Climate Normals 1991–2020. The full USDA table for garlic.