Because of public concern about exposing children to pesticides, legislation restricting its use on school playing fields has increased. One way to manage weeds without chemical herbicides is overseeding or the practice of repetitively seeding with a rapidly germinating turfgrass species. Overseeding for broadleaf weed control was tested on eight fields in Central New York (CNY) for three seasons and 40 fields across the northeastern United States for two seasons. Half of each field was treated each season by overseeding Lolium perenne L. (perennial ryegrass) three to five times each season for a total of 731 kg seed/ha (15 lb per 1000 ft2). Changes in the percent broadleaf weeds, grass, bare ground, soil moisture, Dark Green Color Index (DGCI) of grass cover, depth to soil compaction, and shear strength were measured after each treatment. The percent broadleaf weeds decreased and the percent grass cover increased due to overseeding in the Northeast fields, but not in CNY fields. Depth to compaction, percent soil moisture, and shear strength varied over time in the Northeast fields, and the percent bare ground, DGCI, and soil moisture varied over time in CNY fields. DGCI in the Northeast and soil compaction in CNY were affected by the interaction of overseeding × time. Although overseeding can be a beneficial weed management tool and affect other turf and soil traits in an integrated turf management program, monitoring environmental conditions and supporting field maintenance routines are critical weed management strategies for maintaining healthy turfgrass.