LawnWeather

Pennsylvania Lawn Care Calendar

In Pennsylvania, crabgrass preventer typically goes down between Mar 30 and May 14: first in Philadelphia, last in Erie. Below are typical fertilizer, seeding and frost dates for Philadelphia, Pittsburgh, Harrisburg, Erie, Allentown, Lancaster, Scranton and State College, from 2016–2025 weather data. Enter your ZIP code for this year's timing.

When to apply pre-emergent in Pennsylvania

Typically between Mar 30 and May 14, depending on where you live. The window opens first in Philadelphia (around Mar 30) and last in Erie (around Apr 20). Apply when soil reaches 50°F, before it stays above 55°F.

CityCrabgrass preventer window
PhiladelphiaMar 30 – Apr 20
PittsburghApr 6 – Apr 26
HarrisburgApr 6 – Apr 24
LancasterApr 8 – Apr 24
AllentownApr 10 – May 2
ScrantonApr 13 – May 3
State CollegeApr 19 – Apr 27
ErieApr 20 – May 14

Cool-season lawn calendar

Lawns across Pennsylvania are mostly cool-season grass (tall fescue, Kentucky bluegrass, perennial ryegrass).

CitySpring fertilizerOverseeding & seedingFall fertilizer
PhiladelphiaApr 13 – May 18Sep 2 – Oct 22Sep 28 – Nov 25
PittsburghApr 19 – May 24Aug 19 – Oct 8Sep 7 – Nov 15
HarrisburgApr 17 – May 22Aug 22 – Oct 11Sep 7 – Nov 19
ErieMay 7 – Jun 11Aug 26 – Oct 15Aug 19 – Nov 17
AllentownApr 25 – May 30Aug 14 – Oct 3Sep 2 – Nov 15
LancasterApr 17 – May 22Aug 22 – Oct 11Sep 9 – Nov 15
ScrantonApr 26 – May 31Aug 9 – Sep 28Sep 1 – Nov 10
State CollegeApr 20 – May 25Aug 13 – Oct 2Aug 24 – Nov 11

Frost dates in Pennsylvania

CityLast spring frostFirst fall frost
PhiladelphiaMar 31Nov 16
PittsburghApr 12Nov 2
HarrisburgApr 9Nov 5
ErieApr 27Nov 9
AllentownApr 12Oct 28
LancasterApr 13Nov 5
ScrantonApr 22Oct 23
State CollegeApr 23Oct 27

Median dates, 2016–2025. A dash means frost does not occur in most years.

Frequently asked questions

When should I put down pre-emergent in Pennsylvania?

Typically between Mar 30 and May 14, depending on where you live. The window opens first in Philadelphia (around Mar 30) and last in Erie (around Apr 20). Apply when soil reaches 50°F, before it stays above 55°F.

When is the best time to seed grass in Pennsylvania?

Early fall is best for cool-season grass (tall fescue, Kentucky bluegrass, perennial ryegrass): typically from Aug 9 to Oct 22 across Pennsylvania, while soil cools from 65°F toward 50°F.

What type of grass grows in Pennsylvania?

Most lawns in Pennsylvania are cool-season grass (tall fescue, Kentucky bluegrass, perennial ryegrass).

Lawn care guides

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