FrostCal

When to Plant Watermelon in Pennsylvania

In a typical Pennsylvania location, start seeds indoors Mar 23 – Mar 30, then transplant outdoors May 4 – May 11. Across the state, the outdoor planting window starts as early as Apr 13 in Philadelphia and as late as May 29 in Hermitage.

Method Start indoors, then transplant
Days to maturity 70–90 days

Needs warm soil (65F+); start indoors 3-4 weeks before last frost, transplant 2-3 weeks after last frost.

Watermelon Planting Dates by City

CityStart indoorsTransplant
PhiladelphiaMar 2 – Mar 9Apr 13 – Apr 20
PittsburghMar 27 – Apr 3May 8 – May 15
AllentownMar 23 – Mar 30May 4 – May 11
ErieMar 29 – Apr 5May 10 – May 17
ReadingMar 17 – Mar 24Apr 28 – May 5
ScrantonMar 26 – Apr 2May 7 – May 14
BethlehemMar 23 – Mar 30May 4 – May 11
BensalemMar 24 – Mar 31May 5 – May 12
LancasterMar 22 – Mar 29May 3 – May 10
AbingtonMar 14 – Mar 21Apr 25 – May 2
LevittownMar 24 – Mar 31May 5 – May 12
HavertownMar 2 – Mar 9Apr 13 – Apr 20
HarrisburgMar 18 – Mar 25Apr 29 – May 6
AltoonaMar 28 – Apr 4May 9 – May 16
YorkMar 29 – Apr 5May 10 – May 17
State CollegeMar 23 – Mar 30May 4 – May 11
Wilkes-BarreMar 26 – Apr 2May 7 – May 14
NorristownMar 11 – Mar 18Apr 22 – Apr 29
ChesterMar 2 – Mar 9Apr 13 – Apr 20
Mount LebanonMar 21 – Mar 28May 2 – May 9
Bethel ParkMar 21 – Mar 28May 2 – May 9
WayneMar 11 – Mar 18Apr 22 – Apr 29
RadnorMar 11 – Mar 18Apr 22 – Apr 29
WilliamsportMar 28 – Apr 4May 9 – May 16
MonroevilleMar 25 – Apr 1May 6 – May 13
Cranberry TownshipMar 11 – Mar 18Apr 22 – Apr 29
Drexel HillMar 5 – Mar 12Apr 16 – Apr 23
PlumMar 19 – Mar 26Apr 30 – May 7
Back MountainMar 26 – Apr 2May 7 – May 14
EastonMar 21 – Mar 28May 2 – May 9

Showing the 30 most populous of 121 Pennsylvania cities. Dates are estimates from each city's NOAA frost normals and university extension timing guidelines. See all Pennsylvania cities.

Frequently Asked Questions

When should I plant watermelon in Pennsylvania?

In a typical Pennsylvania location, start seeds indoors Mar 23 – Mar 30, then transplant outdoors May 4 – May 11. Across the state, the outdoor planting window starts as early as Apr 13 in Philadelphia and as late as May 29 in Hermitage.

When is the last frost in Pennsylvania?

The average last spring frost in Pennsylvania ranges from March 30 in Philadelphia to May 15 in Hermitage, based on NOAA 1991–2020 climate normals.

How long do watermelon take to grow?

Watermelon typically take 70–90 days from planting to harvest. Needs warm soil (65F+); start indoors 3-4 weeks before last frost, transplant 2-3 weeks after last frost.

Other Crops in Pennsylvania

When to plant watermelon in other states

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