What’s the best fall fertilizer to apply to St. Augustine grass?

I follow Randy Lemmon Andy these are some that he recommends. You can google him and he has a lot of information about st Augustine grass

Hello Ethel, this should help you prep it for winter

https://www.youtube.com/watch?v=O-rsTi_tC28

Leave fall leaves, run over it with the mower, best fertilizer

Mulch around them with your fall leaves. If you do not have trees or the kind you need, seek out a neighbor up or down the street and ask to rake theirs up to keep for your mulching! They are good for your needs.