I am dealing with the exact same issue right now OAW. It's all of a sudden, grabbed hold of me that I
must fertilize (don't know where I picked it up either) and with the more I'm finding out and with all the additional supplements to go with fertilizing, I'm depleting my fun money account and rapidly.
It can get very expensive. Very generally speaking, from those I've asked, it's been the majority who feel that a bloom booster (every other watering) now through the end of winter is recommended on Catts and Phals. Once Phals start spiking it's also recommended to stop all fertilizing. I've also been using seaweed which is supposed to add green growth and nourish the growth that's already there. I'm not necessarily recommending any of this to you as I'm still in the dark with all of this; I'm just telling you of what I've been recommended. (Everybody has a different opinion on the topic of fertilizing though, that's the problem!) Where my gut reaction is saying, TOO MUCH is to this additional chemical nutrient I just bought called, Floralicious Plus which is to be used, alternating with the bloom booster, one week on, one week off. I keep coming back to the theory, 'less is more' and am seriously thinking of quitting everything except the seaweed supplement and worm tea. There's just too much out there and too many opinions to choose comfortably.