When to fertilize Kentucky bluegrass in Indiana?
By LawnYear editorial team · Published · Updated Windows are read from the extension publications listed under Sources; the dates are approximate.
The answer
The fertilizing windows for Kentucky bluegrass in Indiana are May 1 to May 31, Sep 1 to Sep 30 and Nov 1 to Nov 30, per Purdue University Cooperative Extension Service (1998). High maintenance only: 0.75 to 1.0 lb N per 1,000 sq ft in May, mostly slow release, unless fertilizer went down with a preemergence herbicide in April. Whole month shown. 1 lb N per 1,000 sq ft in September at every maintenance level. 1.5 lb N per 1,000 sq ft in November at every maintenance level, as a fast-release product such as urea after the final mowing while the grass is still green.
Full calendar: Indiana lawn care calendar · Kentucky bluegrass in other states · Lawn schedule by ZIP
Approximate dates for your state. Check with your local cooperative extension office before you act.
All Indiana windows for Kentucky bluegrass
The Indiana calendar on this site lists seeding Aug 15 to Sep 15, fertilizing May 1 to May 31, Sep 1 to Sep 30 and Nov 1 to Nov 30, weed control Apr 1 to Apr 30 and Oct 1 to Oct 31, mowing Apr 1 to Nov 30 at 2.5 to 3.5 in and watering Jun 1 to Aug 31 for Kentucky bluegrass.
Where the dates come from
Purdue University Cooperative Extension Service: AY-27, Maintenance Calendar for Indiana Lawns (1998); month-by-month calendar for cool-season grasses at high, medium and low maintenance levels. Read on 2026-10-30.
What to check for Indiana
The fertilizing dates for Kentucky bluegrass above (May 1 to May 31, Sep 1 to Sep 30 and Nov 1 to Nov 30) apply to Indiana as a whole, so the north and south of the state are not told apart. Where the source names only a month, the window runs from the first to the last day of that month.
Other grasses in Indiana
For tall fescue, perennial ryegrass and fine fescue, the Indiana calendar gives May 1 to May 31, Sep 1 to Sep 30 and Nov 1 to Nov 30 for fertilizing.
Fertilizing Kentucky bluegrass in other states
- Virginia: Aug 15 to Oct 31 and Mar 1 to May 31, per Virginia Cooperative Extension (Virginia Tech), 2025.
- Pennsylvania: Apr 15 to May 31 and Aug 15 to Oct 15, per Penn State Extension.
- Ohio: Apr 1 to May 31 and Oct 1 to Nov 30, per Ohio State University Extension, Lake County (2007).
- Missouri: Apr 1 to Apr 30 and Sep 1 to Oct 31, per University of Missouri (Integrated Pest Management), 2015.
- Kentucky: Oct 1 to Nov 30, per University of Kentucky Cooperative Extension Service (2014).
- Wisconsin: Sep 1 to Sep 15 and May 20 to Jun 10, per University of Wisconsin-Madison Division of Extension (2022 and 2025).
- New Jersey: Aug 15 to Sep 30 and Nov 1 to Nov 30, per Rutgers Cooperative Extension (NJAES), 2023.