Q: In an online article about mowing zoysia, you say that de-thatching could be accomplished by topdressing with a quarter-inch layer of clean topsoil. When is the best time to apply the topsoil?

A: The best time to topdress is after your lawn is 100% green in spring, typically in early May. The topsoil inoculates the thatch with fungi which decompose the grass clippings naturally.