Bananas and passion fruits are not common to the temperate areas of the world. The bananas that are sold in markets are not fertile and, although they have tiny black specks in them, these are not seeds. Wild bananas are filled with large seeds that take up most of the interior of the banana. If you happen to get some of these, the seeds can be planted for a rapidly growing tropical lush plant. The passion fruit seeds can also be planted in the same way, to get an aggressively growing vine with attractive foliage, and you will probably also get some edible fruits from it.
Break up the ground in the sunny spot you have chosen. The soil will need to be fast draining so a fertilizer should be applied every week or so. A good site for the passion fruit vine would be by a fence where it will have plenty of room to grow, while the banana tree will need a spot with plenty of room for high growth (up to 25 feet high).
Plant the seeds when the soil has warmed to at least 50 degrees Fahrenheit in soil about 1/2 inch down for the passion fruit and about 1 inch down for the banana seed. Cover them over with the soil and tamp it down so the soil makes good contact with the seed. Place some logs or wood near the passion fruit to encourage carpenter bees to nest. They are necessary for pollination if you are interested in trying to grow fruit.
Keep the soil moist but not puddling, until the new growth is visible. Apply a high nitrogen fertilizer at least once a week. The passion fruit vine can be pruned to keep it in check as it will grow wildly. Keep weeds away from the base of the plant but be careful with the passion fruit since it has a shallow root system so weed by hand or by using a safe herbicide.
Mulch the banana plant heavily before the first frost. It will die off in the cold weather but the rhizomes underground may be able to withstand the cold. In areas with temperatures below freezing for several weeks, the roots should be removed from the soil and stored in a dry cellar or garage at about 40 degrees Fahrenheit until spring. The passion fruit will also die in the cold weather and can be grown from seed again in the spring.