I think I've been growing my dragon fruit now for a 3yrs. Honestly, I do not do a great job of taking care of it. It's because if grows so out of control! and I have 300 Fig pots that occupy my time.
It's got prickly spines and likes to behave like a vine, making it a bit treacherous to get snagged on. I have a tomato trellis hold it up. but it's getting a bit heavier than the trellis can handle.
So far it loves being in partial sun on the deck. You can see the difference between indoor and out door growth. The indoor growth is much more skinny and lanky.
Typically these dragon fruits can take up to 6yrs to fruit so I'm not holding my breath waiting for it to flower. For now I will continue keeping this plant for another few years. I'm determined to see it fruit!