Originally Posted by Smallaxe
This is a strange custom that you southerners have for your turf... Why is that?
Topdressing began as a practice used on the cool season golf courses of Scotland in the late 1800s.
Topdressing with sand has several benefits, including OM dilution (too much OM reduces water infiltration, gas exchange, and OM mineralization), thatch reduction (via increased microbial activity), crown protection, increased water infiltration, increased gas exchange, and site leveling.
In lawns, the influence of OM in the rootzone is much less significant than it would be in golf course putting greens, so those topdressing benefits related to OM management aren't as noticeable. But, whether you're managing bermudagrass in Georgia or Kentucky bluegrass in Wisconsin, sand topdressing can help to level out the bumps in an unlevel lawn.