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Sports field construction contracts in cool-season areas often stipulate a 9- to 12-month period between seeding and opening for play. Seed mixtures are usually dominated by slow-establishing Kentucky bluegrass (KBG; Poa pratensis L.) and contain lower proportions of perennial ryegrass (PRG; Lolium perenne L.) for quick cover. Our objective was to evaluate the effect of planting time on three KBG : PRG mixes, a 100% PRG blend, and their ability to sustain football-type traffic. Field plots were seeded in late summer, as a dormant planting in late fall, and in the following spring. Plots received simulated football traffic, split for one or four weekly games, from mid-August through mid-November of the year in which spring seeding occurred. The experimental design was a strip-split-plot, randomized block with four replications. The study was repeated a second year. All seeding dates provided acceptable turf quality regardless of seed type by September. However, summer seedings of KBG-based mixtures provided better turf quality than mixtures planted in the spring, whereas dormant-seeded mixtures provided the poorest turf quality. Turf seeded with 100% PRG was less sensitive to seeding date, with summer or spring seedings providing similar quality and dormant seedings superior to KBG-based dormant seedings. Summer seedings also resulted in the least amount of broadleaf weeds the next year with dormant seedings having the most weeds, particularly with plots seeded to 95% KBG. All KBG-based seed mixtures provided turf containing ≈50% KBG or more by September, although the amount of KBG remaining after traffic was significantly greatest in plots seeded to 95% KBG and least in plots seeded with 70% KBG. Pure PRG swards provided acceptable turf quality throughout the traffic period but should be used cautiously as a result of winterkill potential and crown rust disease (Puccinia coronata Corda f. sp. agropyri Erikss.). Different amounts of traffic did not affect turf species proportions. The most consistently desirable results may be obtained with a mixture containing 70% to 80% KBG and 30% to 20% PRG, respectively. Mixtures dominated by KBG should be seeded in late summer for best results.

Roughstalk bluegrass (Poa trivialis L.) is a troublesome weed on golf courses, home lawns, and athletic fields from the Midwest to the mid-Atlantic states. Bispyribac-sodium and sulfosulfuron have recently been labeled for roughstalk bluegrass control, but their use needs to be refined. Our objective was to determine the most effective herbicide strategies for control of roughstalk bluegrass. Initial studies were conducted during 2005 in Illinois and Indiana and follow-up studies in 2006 in Indiana, Illinois, South Dakota (partial shade and full sun), and Wisconsin. Applications starting in the warmer temperatures of late May and June 2005 were more effective than those starting in mid-May. Bispyribac-sodium (a.i.) was applied at 74 or 114 g·ha⁻¹ four times at 2-week intervals decreased roughstalk bluegrass cover to 1% and 0% 12 weeks after initial treatment (WAIT) in Illinois and Indiana in 2005, respectively, whereas sulfosulfuron (a.i.) at 13 or 27 g·ha⁻¹ applied twice at 2-week intervals decreased cover to no less than 18%. In 2006, bispyribac-sodium was most effective in Indiana and Illinois decreasing cover to as low as 4%, whereas sulfosulfuron was most effective in South Dakota resulting in a decrease in cover to as low as 7%, and both herbicides performed similarly in Wisconsin. Three applications of sulfosulfuron (a.i.) at 27 g·ha⁻¹ at 2-week intervals or four applications of bispyribac-sodium (a.i.) at 56 or 74 g·ha⁻¹ at 2-week intervals were most effective for roughstalk bluegrass control.