Research conducted at the University of Wisconsin concluded that over a 12 month period under ideal maintenance, the best quality KBG+PRG stand was obtained with Compact Kentucky bluegrass types. The next best performers were the Aggressive Kentucky bluegrass types. Common types were not favored.
Seed mixtures contain 2 or more species, for example Kentucky bluegrass (KBG) and perennial ryegrass (PRG).
Although Kentucky bluegrass fields make up the best quality sports fields most have been seeded as a Kentucky bluegrass and perennial ryegrass mix, usually an 80:20 mix. Perennial ryegrass should not make up more than 20% of the mix in a new seeding because it is not as wear tolerant or winter hardy as KBG and because over time the PRG could become the dominant species.
Seed blends contain 2 or more varieties of the same species. A dense turf stand can be achieved by blending improved varieties. Use a couple of the highest quality varieties that contain the desired characteristics (wear tolerance, recuperative potential, resistance to stress, establishment speed, color, etc.) desired for your situation.
Sample seed label