Personally in all my expiditions using a blind a floor is not needed! Simply remove and leaf litter or brush and sit down. If you set up the blind in advance spray the area with Raid YardGuard.....that will kill anything in and around the ground litter or brush.
JW
What if you leave the blind up all season? Do you repeatedly spray? I don't see how a floor in a blind would keep out bugs, spiders, snakes, field mice etc.