I use 5 blend turf fescue mix Spring time is a good time to seed as long it hasn't been treated for crab grass.
Keller's out of Quincy ILL They buy and bag all there seed Some Seed you buy at the Box Stores could be older seed depends how long sits there
I do more Lawn installs in spring time then fall with no problems I always give a 1 year warranty on new seeding
There few key factors Soil test,proper seed bed depth, use thin layer of copper up straw
Snyder's New Lawn Service Inc.