Overseeding to change varieties

Switching turfgrass varieties by overseeding is difficult - some would say futile. However, the practice of routine overseeding in order to change varieties has gained acceptance over the past decade. Although formal research is scanty, anecdotal results seem to support the process of routine overseeding/interseeding that can result in slow displacement of undesired turf varieties, such as Poa annua. Of course, seed producers and distributors are very supportive of the idea of overseeding. But does the data support the process?…