The passion vine (Passiflora spp.) hails from South America. Gardeners prize the vine for its vigorous growth, glossy foliage and bright blossoms that add texture and color to any backyard. Though passion vine seeds can often be purchased from garden stores, those with access to an existing passion vine or passion fruit can harvest and prepare seeds on their own.
Wait for the passion vine's fruit to mature for harvest. A mature passion fruit measures anywhere from 1 1/2 to 3 inches in width with either a dark purple or a light yellow color, depending on the specific variety. It typically takes 80 days from flowering for the fruit to be ready, according to the California Rare Fruit Growers association.
Pluck the fruit off of the vine with your hand, pulling it away from the vine at an angle.
Cut the fruit in half with a knife to reveal the small, black seeds inside.
Scoop the cluster of seeds in the middle of the fruit into a sieve or kitchen strainer. Run water through the strainer to help rinse away the fruit's juices and any pieces of fruit that's clinging to the seeds.
Spread the seeds onto a paper towel or newspaper and allow them to dry for several days.
Empty the dried seeds into a sealable container for storage until you're ready to plant them.