How big is the plant? Can you post a picture?

Should I put some type of stick in it so it can trellis up it?

I am also wondering about the type of water I should use to water it. I have well water but my husband has installed a filtering system and a reverse osmosis. I use distilled water for my picture plants, filtered ice cubes for my orchids, and the filtered well water for all the rest of my houseplants and herbs.

I mostly have plants outdoors in pots and the ground but I would try to pull the plant out of the pot and see if it is rootbound. If you see a lot of roots on the side of the dirt I would pot it up to the next size up. Passionfruit seems to want to grow onto anything. My wife and I setup an archway trellis and our passionfruit is growing all over it. It's a lot faster grower than the kiwi and raspberry on the other side of the archway.

As to RO water I haven't heard of anyone having issues. I just use regular tap water for my plants. I have heard water softeners can be bad because of salt buildup.

There are some more experienced posters that might have some more knowledge and I am sure they will chime in. This is my first year growing.