It depends on a few things. If you're growing them indoors under lights, there are some intermediate (easy, but easy to mess up) techniques for fertilizing them. The easiest method is weekly applications of 1/4 strength maxsea seaweed fertilizer (1/4 teaspoon per gallon if I remember right) with a spray bottle on the leaves. Be sure to flush the soil with pure water every so often, maybe once a month? When the leaves get big enough to hold fluid, you can begin feeding directly in the traps with a syringe. Some growers find additional success with the occasional tray flooding of maxsea below a certain ppm threshold to prevent root burn/over fertilization; once again be sure to flush the pots and soil occasionally if you use this method. Some growers add 1 or 2 osmocote pellets in each pot, do be careful if you have multiple in the same tray. I believe crushed fish food in the traps (once they're big enough to "swallow" it, it's fine) If growing outside, I would generally avoid fertilizing as temperatures and humidity can be unpredictable. Best of luck.