Kentucky Bluegrass Management Calendar

This calendar is a basic guide to Kentucky bluegrass management in Nebraska and much of the Great Plains. Different locations and weather conditions within the region may alter dates by three weeks or more.

Zac J. Reicher, Extension Turfgrass Specialist
Keenan L. Amundsen, Turfgrass Geneticist
Anne M. Streich, Assistant Professor of Practice
Fred P. Baxendale, Extension Entomologist
Loren J. Giesler, Extension Plant Pathologist

Dates Fertilization Cultural practices Pest control Notes
April   Begin mowing as needed.   Mow at 3.0 to 3.5 inches as needed to avoid removing more than 1/3 of the leaf blade. Mow at this height throughout the year.
April 15 - May 1     Apply preemergence herbicide for crabgrass control. Most preemergence herbicides are only available with N as the carrier. Try to limit N rate to 0.75 lb N/1,000 sq ft and use products containing 25 to 50% slow release N*.
May     Treat for billbugs if history dictates. Watch for adult billbug feeding symptoms or activity in full sun near sidewalks. Treat if damage is seen and/or if history of billbug damage.
May 1 - June15     Treat for summer patch if history dictates. Once 2-inch soil temperatures reach 65°F, apply summer patch fungicides if lawn has a history of summer patch. Repeat application 4 weeks later.
May 1 - June 1 0.75-1.0 lb N/1,000 sq ft     Apply nitrogen only if not applied earlier in the spring, and use products containing 25 to 50% slow release N*.
June through September   Irrigate to prevent drought stress.   Kentucky bluegrass is more drought tolerant than most homeowners suspect, so requires infrequent irrigation.
June through September     Scout for dollar spot. Dollar spot is favored by warm, humid weather with cool nights (60°F to 85°F temperature range for activity). Dollar spot can usually be minimized in homelawns by increasing annual nitrogen rate by increasing N applied in the fall. Fungicides are not usually recommended on lawns except only in extreme cases.
Mid-June     Treat for white grubs if history dictates. Apply preventive insecticides for white grubs if lawn has a history of grub damage.
August 15 - September 1   Overseeding   Lawns thinned from summer weather or damaged from pests can be overseeded with newer cultivars of Kentucky bluegrass. Overseeding is most successful on very thin lawns and when combined with aerification to improve seed-soil contact.
September 1-15 0.75-1.0 lb N/1,000 sq ft     Use products containing 25 to 50% slow release N*. Phosphorus and/or potassium can be applied now if soil tests dictate.
September 15 - October 15   Aerification   Use hollow tines for maximum reduction in compaction. Could be combined with overseeding with a blend of Kentucky bluegrass if turf is thinned from summer.
September 15 - October 15     Apply postemergence herbicide broadleaf weed control. Fall is ideal time to control broadleaf weeds. Second best time is in the spring at or shortly after flowering of dandelions.
October 15 - November 1 0.75-1.0 lb N/1,000 sq ft     Apply nitrogen near the last mowing and use products containing no slow release N.
October 15 - November 1   Continue mowing until lawn stops growing.   Continue mowing at 3.0 to 3.5 inches until lawn stops growing.
*% slow release N = total % of slow release forms listed on the label ÷ % of total N.

More information is available at UNL’s Turfgrass Science Program website: http://turf.unl.edu/.

This publication has been peer reviewed.

Visit the University of Nebraska–Lincoln Extension Publications website for more publications.
Index: Lawn & Garden
2006, Revised August 2012