Rule number one of keeping a Nepenthes is that you keep the fertilizer far, far away. Some horticulturists have had success with foliar feeding, but I don’t yet trust myself not to hurt mine — they’re more delicate than they seem, sometimes.
Carnivorous plants are carnivorous because their roots are not well adapted to extracting nutrients from their substrates. That’s why they eat bugs. Digestive enzymes are nature’s way of making sure they get fed, roots or no. Well… Unless they’re one of the types that evolved to digest fallen leaves or be a sleeping bag for bats, but I digress.
My N. ventrata’s pitchers are still fairly tiny (there are a bunch of them now, though), and my apartment is mercifully bug-free aside from the occasional spider or stray stinkbug, so there isn’t much hope when it comes to leaving my plant to its own devices. If it’s hoping to catch a meal here, it’s going to be very disappointed for a very long time.
That’s okay, though. I’ve got this covered.
Pitcher plants are easier to hand feed compared to Venus fly traps. For fly traps, you have to rehydrate dried insects into a kind of bug-burger, then wiggle it around until the trap activates. Too much water, and the liquid might cause the plant to rot. Not enough, and the plant’s digestive enzymes might not be able to break it down adequately.
Pitcher plants, though? They’re a breeze:

Nepenthes pitches contain so much liquid, rehydration isn’t really an issue. They also lure insects rather than trap them, so I don’t have to put on a dead bug puppet show to get them to latch on. Take a pair of tweezers, pick up a pinch of dried bloodworms, and drop them in. You can even crush the worms to powder for particularly small pitchers. It doesn’t take many, so one container will last for ages.
Larger pitchers benefit from dried crickets or mealworms instead, but my guys are much too little for that. Pinhead crickets are often available as a special order from some pet stores, but they usually only come in large increments. I also don’t want to have to fight with fitting live crickets into those tiny pitcher mouths!
Feeding is kind of a misnomer, though — nepenthes are still photosynthetic, and depend on carbohydrates for energy. Bugs are more akin to fertilizer than actual food. As with other types of fertilizer, it’s better to err on the side of not feeding enough versus feeding too much. I don’t feed my pitchers often — once a month, if that. Regardless of what you feed them or how often, it’s important to make sure that the insects are completely submerged in the digestive fluid. If they aren’t, they’ll just end up growing mold instead of breaking down and feeding the plant.
Hopefully, I’ll have some pitchers large enough for crickets soon. Until then, I’ve got loads of bloodworms!