I do it 3 times each year. In early spring, a broadcast slow release scattered. In late spring, one gallon per plant of Alfalfa tea, In Summer, I use Mills Easy Feed concentrate and feed each plant about 1 gallon
There are lots of fertilizing options out there. This is just what I do. I personally stop fertilizing after mid-September in my climate, to prepare for winter. Your climate may be vastly different. I’m zone 5a