Sports fields in the Upper Midwest typically are seeded to mixtures of Kentucky bluegrass (KBG) and perennial ryegrass (PRG) (Poa pratensis and Lolium perenne) with various ratios to provide a durable turf with a reasonable establishment rate. Field construction contracts commonly specify an establishment period prior to play, however, scientific data to support any one establishment period are scarce to nonexistent. Our objective was to determine if planting date affected the utility of a given seed type compared to another. We planted KBG:PRG mixtures with ratios of 70:30, 80:20, and 95:5 (wt:wt) and a monostand of PRG at three times: late summer (conventional recommendation), late fall (dormant), and early spring. Traffic was applied to simulate one or four football games per week between mid-August and mid-November to determine if seed types and planting dates had different responses to traffic levels. The study was repeated a second year. Results varied between years in part because plots seeded to 100% PRG suffered partial winterkill the first year. While all KBG:PRG mixtures established slower than 100% PRG, the 95:5 mixture resulted in poorer quality than all other seed types in year two. All three mixtures provided over 50% KBG in the sward through October but only the 95:5 mixture maintained more than 50% KBG by mid-November. KBG:PRG mixtures provided best results when seeded in late summer though early spring seedings were not much different by October. Dormant seedings provided the worst turf quality and the greatest number of turf weeds, particularly for KBG:PRG mixtures. Turf seeded to 100% PRG provided better quality only until mid-summer compared to mixtures when seeded in late fall or spring. KBG:PRG mixtures provided more reliable turf quality than 100% PRG but need to be seeded by late summer in order to ensure sufficient turf quality the following August.