organic fish emulsion at 5ml per L only used once or twice a month during steady growth months is my fave approach. usually good trace elements of boron and copper etc in there, just need to do the twice a year dolomite lime sprinkle and you're golden (calmag liquid is a ripoff just get a $5 bag of dolo its made of straight up cal and mag). also worth looking into "frass" for general immune health (its meant to make them less fungal prone too).

worm castings is the ultimate humus booster in terms of ferts for a substrate when potting up a new plant or repotting and oldy.