on my P.Incarnata I can open a green fruit and the seeds are ready,... but I don't know about other types.
most people let it turn and then take out the seeds clean them and dry them and then store them
the seed should be dark in color brown or black most of the time.
I take the fruit when it is at just the right size to eat fresh off the vine and keep the seed for planting and trade.
I clean them and dry them on a plate then put them in a baggie and in to my seed box in the fridge.
I hope this helps have a good day.
Robbie

For best results, Passionfruits should fall off the vine on their own. Open the fruit and eat the pulp, spitting out the seeds. Wash and then dry the seeds briefly and plant ASAP. Paul.

Open it & plant the seeds.

You have to get the goo off- easiest way to do that is put them all in a wire strainer & run water over them while rubbing them against the screen. Once the water runs clean place the seeds on a paper towell or somesuch & let dry- Then you can easily remove the rest of it by rubbing the seeds together.

Then you can save or plant them- Hopefully you'll have a couple hundred, but I've opened egg sized fruit to olny find one seed. It's a caerulea X lady margaret hybrid I tried.. Hopefully it grows.

Your seeds should be dark brown to black- If your in doubt, soak them in a cup of water overnite. Any that float in the morning are dead- all the sinkers should be Ok.