How do i germinate passion flower (passiflora caerulea) seeds?

It says that i should start the seeds 10-15 weeks before the last frost and they should be soaked for 24 hours and prechilled before seeding. They also say that they are perrennials and they are hardy in zone 5, and i should bring them indoors for winter. I live in zone 5. I don't get that if they are perrennials and they are hardy in zone 5 why should i bring them in for winter?

How do i germinate passion flower (passiflora caerulea) seeds?
There are ways to improve the keeping qualities of passiflora seed but, in general, it is best to use fresh seed which germinates readily. Seed that has been stored for any length of time can take up to 12 months to germinate with less than 2 per cent chance of success.





To improve germination, lightly sandpaper the seeds on one or both sides using fine sandpaper, then soak them in tepid water for 24 hours. Sow 2-5mm deep in peat or soil based seed compost. Temperature is probably the most important factor in germination, ideally at 20 degrees C (68F) for 16 hours and 30 degrees C (86F) for 8 hours each day. If this is not possible, then a constant temperature of 26 degrees C (79F) is advisable. Using this technique fresh seed germinates in two to four weeks and older seed in four to eight weeks, but 12 to 48 weeks is not exceptional.





Having germinated your seed and over wintered your young plants, your next goal is to get them flowering. As we know only to well, many plants grown from seed can take years to flower. Passion flowers are no exception. Some species are said not to flower until they are 10 or 20 years old. I don't believe this, but have had some passion flowers that have not flowered for eight years. If you have grown P.caerulea from seed and found it reluctant to flower - sorry! Some seedlings never do.





Although Passion flowers are considered hardy in USDA zones 5-9, they should be planted in a protected location and mulched heavily if severe cold threatens. The top growth is killed back by frost, but 'pops' back to life in the Spring.
Reply:" I live in zone 5. I don't get that if they are perrennials and they are hardy in zone 5 why should i bring them in for winter?"





:-) Me neither, as far as I'm concerned passion fruit vines are not a suitable plant for permanent container growing. I don't go much on the pre chilling either. Passion fruit seed are not difficult to grow, but the seed has a very hard outer coat and takes a while to germinate sometimes. Where I live we get a couple of light frosts a winter and temperatures in the thirties most of summer.





I'd plant them a cm deep in seed trays cover with plastic film and keep damp. In hot weather i'd keep them in the shade. snails will eat new germinations to the point you never knew it happened, so some protection needed there.





Good luck :-)
Reply:once you get them started the coldness of the winter will kill them as they are only little and need sunlight to make them grow, so place them in a window for the sunlight and keep them watered
Reply:They wont flower if you don't