It depends! While we can supply general fertilizer recommendations based on the type of grass you have and the time of year you plan to fertilize, the most foolproof way to fertilize is to first get a soil test done. This lets you know what the fertility is like in your lawn and allows you to better determine what nutrients you need to apply to keep your lawn healthy and thriving.
Additionally, we recommend you check out this reference from Oklahoma State University’s Division of Agricultural Sciences and Natural Resources for common lawn fertilizer applications.