They don't call them tropical passionfruit for no reason. In a climate with cooler winters you want a purple passionfruit ( P. My climate is tropical and I grow the tropical kind, both golden and purple flavicarpa (i.e. Like all fast growing plants passionfruit needs a lot of nutrients. That lush green foliage has to come from somewhere, it can not materialise out of nothing.
So passionfruit vines need fertile soils, probably additional fertiliser, and they appreciate all the compost and mulch you can spare. They also need full sun, a warm climate, and protection from wind. A sunny, sheltered site in a frost free climate is ideal. There are some purple varieties that can handle the odd very light frost. And sometimes, even though the top of a vine is killed by frost, the roots reshoot. However, the warmer the climate, the easier it is to grow passionfruit. A fence, a water tank, a trellis, anything will do. Watch where you plant them, because they will be up in the crown of a nearby tree before you know. A healthy soil, teeming with worms and microbes and lots of organic matter is your best bet.
If your soil is poor you will get problems with wilt diseases, root rot and nematodes. Heavy clay soils also cause problems with rot diseases. Watering: The root system of a passionfruit vine is small for the size of the plant it has to sustain. Especially while a passionfruit is fruiting it needs a lot of water. However, passionfruit can't handle waterlogged soil. If I can grow something from the seed of store bought fruit, even better. Why spend money on a nursery plant if you don't need to? For some reason old seed takes a lot longer to germinate. So buy some nice passionfruit, separate half a dozen seeds from the pulp, and plant them as soon as possible. If you buy your seed then it's likely older, so be prepared to wait. Old passionfruit seeds can take months to germinate. The best way seems to be to just put them in the garden and leave them be, and eventually they come up. There are some tricks like soaking the seeds in warm water first, and some people swear by vinegar. Others report their acidic soil seems to do the job. Whenever I used fresh seed it came up without problems. Seeds of hybrid varieties do not grow true to type. If you live in a cooler climate the passionfruit you buy may be a hybrid variety. If you grow that seed you don't know what kind of fruit you will get. It will be nothing like the parent plant and probably not very nice.
Find out what the fruit is that you buy, or buy the seed so you know what you are planting, or even buy a plant from a nursery. Another reason for not growing passionfruit from seed is the high susceptibility of the purple varieties and the hybrids to the root disease Fusarium wilt . Luckily, resistant root stocks exist (flavicarpa varieties). If Fusarium wilt is a problem in your soil, and if you need to grow susceptible varieties because of your cool climate, then you may want to invest in a grafted plant from a nursery.
All tropical passionfruits are reasonably resistant to Fusarium wilt and they are also more resistant to nematodes, another problem when growing passionfruit.