The blades are 2 inches apart, I seed here in ky at 6lbs/1000 with my machine then use my broadcast tho put a little more on over the top for perfect coverage. I single passed my yards with great turf and the machine still gave excellent results, for the low maint. yards with crabgrass the double pass pulled up much of the crabgrass and i swept it off. My routine for a double pass on a yard with alot of thatch is 1)slit seed with seed one direction 2)sweep with my pull behind sweeper 3)slit seed other direction with seed 4)sweep again 5)broadcast to ensure complete coverage. I get great results using LESCO/JD 3 way Tall Fescue blend in 10-12 days on about every yard which makes the customer very happy. I screened the first load of thatch we took off and only found <.5 lb of seed in the thatch so the double sweeping isnt taking much seed up at all.