My Nepenthes ventrata a month ago and now.
Even though carnivorous plant enthusiasts tell you to never fertilize these, they can still benefit from it if you do it correctly. I heavily diluted (quarter strength) the plant food I use for my succulents and applied a few drops directly on the leaves. A week later it started a growth spurt and produced these huge pitchers.
This doesn’t work if you add fertilizer to their water as it will burn the roots and possibly kill the plant.