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4 grasses · extension sources

Lawn care calendar for Pennsylvania.

Penn State Extension covers cool-season grasses for Pennsylvania, with a seeding window, two nitrogen windows and crabgrass timing that varies by area.

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By LawnYear editorial team · Published · Updated Windows are read from the extension publications listed under Sources; the dates are approximate.

Short answer for Pennsylvania

In Pennsylvania, for Kentucky bluegrass, perennial ryegrass, fine fescue and tall fescue, seed Aug 15 to Oct 15; fertilize Apr 15 to May 31 and Aug 15 to Oct 15, per Penn State Extension.

The same calendar gives weed control Mar 15 to May 15.

Approximate dates for your state. Check with your local cooperative extension office before you act.

Windows by grass and task

Lawn care windows in Pennsylvania by grass and task, from the extension sources listed under Sources. Dates are approximate.
GrassSeedFertilizeWeed controlSource
Kentucky bluegrassAug 15 to Oct 15Apr 15 to May 31Aug 15 to Oct 15Mar 15 to May 15Penn State Extension, 2025Penn State ExtensionPenn State Extension, 2016
Perennial ryegrassAug 15 to Oct 15Apr 15 to May 31Aug 15 to Oct 15Mar 15 to May 15Penn State Extension, 2025Penn State ExtensionPenn State Extension, 2016
Fine fescueAug 15 to Oct 15Apr 15 to May 31Aug 15 to Oct 15Mar 15 to May 15Penn State Extension, 2025Penn State ExtensionPenn State Extension, 2016
Tall fescueAug 15 to Oct 15Apr 15 to May 31Aug 15 to Oct 15Mar 15 to May 15Penn State Extension, 2025Penn State ExtensionPenn State Extension, 2016

Calendar by grass

Grasses the source covers with one shared calendar are shown together. Open a group for each task, its note and its source. Want dates for your ZIP code? Use the lawn schedule by ZIP tool.

Kentucky bluegrass, perennial ryegrass, fine fescue and tall fescue

4 tasks

  • Kentucky bluegrass, perennial ryegrass, fine fescue and tall fescue in Pennsylvania

    Seed

    Aug 15 – Oct 15

    Late summer is the optimum time to seed in most of Pennsylvania (late August and early September); seeding later than mid-October is not suggested. Start date is interpreted from 'late summer'.

    [1]Penn State Extension (2025)(opens in a new tab)[2]Penn State Extension(opens in a new tab)[3]Penn State Extension (2016)(opens in a new tab)

  • Kentucky bluegrass, perennial ryegrass, fine fescue and tall fescue in Pennsylvania

    Fertilize

    Apr 15 – May 31

    Nitrogen is applied in mid- to late spring and/or late summer to early fall; follow the label rate. Window is interpreted from 'mid- to late spring'.

    [2]Penn State Extension(opens in a new tab)

  • Kentucky bluegrass, perennial ryegrass, fine fescue and tall fescue in Pennsylvania

    Fertilize

    Aug 15 – Oct 15

    Nitrogen is applied in mid- to late spring and/or late summer to early fall; follow the label rate. Window is interpreted from 'late summer/early fall'.

    [2]Penn State Extension(opens in a new tab)

  • Kentucky bluegrass, perennial ryegrass, fine fescue and tall fescue in Pennsylvania

    Weed control

    Mar 15 – May 15

    Preemergence herbicide for crabgrass in early to mid-spring: March 15 to April 15 in southeastern Pennsylvania, April 1 to May 1 in other areas, April 15 to May 15 in the northern tier and high-altitude counties. The union is shown; use your area's window.

    [2]Penn State Extension(opens in a new tab)

Kentucky bluegrass in other statesPerennial ryegrass in other statesFine fescue in other statesTall fescue in other states

Cool-season species only

Penn State's species page lists the cool-season grasses adapted to Pennsylvania, and the calendars below apply to Kentucky bluegrass, perennial ryegrass, fine fescue and tall fescue. This site has no warm-season calendar for Pennsylvania and has not recorded mowing or watering windows from the three Penn State pages used here, so those tasks are not shown.

Seed in late summer

Penn State calls late summer the optimum time to seed in most of Pennsylvania, meaning late August and early September, and does not suggest seeding later than mid-October. The mid-August start on the calendar is this site's reading of 'late summer'.

Nitrogen in two seasons, rates on the label

Nitrogen is applied in mid- to late spring and/or in late summer to early fall, following the label rate. This site recorded no pounds-per-1,000-sq-ft figure for Pennsylvania, and both windows shown are this site's reading of those season words.

Crabgrass preventer depends on where in Pennsylvania you live

Preemergence timing is March 15 to April 15 in southeastern Pennsylvania, April 1 to May 1 in other areas, and April 15 to May 15 in the northern tier and high-altitude counties. The statewide calendar below shows the union, March 15 to May 15, which is wider than any one area's window. Use the window for your area.

Sources

The dates and figures on this page come from these publications.

  1. [1]
    Penn State Extension ↗ (opens in a new tab)Lawn Establishment (September 2025).Publication year 2025 · Read 2026-10-29
  2. [2]
    Penn State Extension ↗ (opens in a new tab)Lawn Management Through the Seasons.Read 2026-10-29
  3. [3]
    Penn State Extension ↗ (opens in a new tab)Turfgrass Species for Pennsylvania (2016); lists the cool-season species adapted to Pennsylvania.Publication year 2016 · Read 2026-10-29