Originally Posted by Smallaxe
Taking dead grass and similar organic materials out of the turf is like stripping paint off the car so it holds wax better...
you seed will do much better in dead grass clippings than on bare soil,,, therefore bagging when mowing and dethatching and removing that asset is an error...
This is not entirely true. What if a lawn had never been de-thatched? Are you going to make a 'trial' pass with the slit seeder and wind up pulling up excessive thatch to the point it is not failing to allow irrigation through? That partially decayed organic mat does a horrible job at retaining water. When the thatch layer is excessive, it should be bagged. When you make your seeding passes, any extra thatch can be left where it is.
I mulch mow my lawn 100% of the time. The only time I will ever bag is when I'm preparing to slice seed.