Bananas are without a doubt one of the most economically important plants in the world, so it makes sense that most people don't often think of growing bananas indoors. That's a shame, though. Because of the way bananas grow, you can create a stunning, large and very tropical summer container display using bananas. Providing you give it enough water and fertilizer, the banana plant will grow extremely fast, filling in your bright corner or window in no time at all and providing a wonderful conversation piece. There is one drawback, however. Don’t expect to actually harvest any bananas. Unless you live in the tropics or have a large greenhouse, your plant won't have time to flower and develop fruit. Instead, focus on growing bananas for their beautiful and signature foliage.
Light: Bananas grow in full sun or dappled shade.
Water: During the growth season, bananas are prolific water hogs. Water the plant generously, and as it grows, expect it to consume more water. You may find yourself watering a large banana plant daily.
Temperature: On the warm side (up to 85˚F). If you keep the plant during winter, try to keep the temperature as warm as possible, with high ambient humidity.
Soil: A loose, well drained, very rich potting mix.
Fertilizer: Fertilize abundantly. Bananas are notoriously heavy feeders, so provide a steady supply of nutrients, in whatever form you're using.
Bananas are very easy to propagate because of their unique growth habit. The actual banana "trunk" is really a large pseudobulb composed of old leaves that grows from an underground rhizome. In nature, each stem grows to maturity, flowers and fruits, and then dies back. Meanwhile, the underground rhizome is continuously sending up new stems to keep the plant active. On banana plantations, growers usually cut back extra stems as they emerge so each rhizome will have only three trunks at any given time: one immature trunk, one flowering trunk, and one fruiting. This ensures a steady supply of bananas. Thus, propagating bananas is a simple matter of digging up and dividing new stems as they emerge, making sure to include a bit of the rhizome and roots. However, it's unlikely your plant will live long enough indoors to begin sending up shoots (which is usually at least a year or more), so it's likely you'll discard your plant after one season.
A truly mature banana plant cannot be properly contained in a single container because, over time, the plant will send up numerous shoots and outgrow whatever container you're using. If, however, you live in a warm region and want to keep your banana beyond a single season, follow these tips for repotting. First, remove all suckers as they emerge and pot into smaller containers (1 gal. is perfect for small shoots), leaving only the main trunk. Then repot the main trunk in the spring into a larger container. Remember, however, that each banana trunk is designed to only live for a few years at most and will die after flowering. So don't expect to grow a long-lived "banana tree" in your house.
There are about 40 species of bananas in the wild, but untold hybrids have been created, including eating bananas like the Cavendish, Ice Cream, and Grand Nain. I'd recommend choosing your banana cultivar based on its leaves since you won't be growing for fruit. The red-leaved bananas (sometimes called 'Bloodleaf') are beautiful container plants with variegated red and green leaves. Bananas are closely associated with the bird of paradise and for a long time, the plants were placed in the same family.
A healthy banana plant will have upright, very tropical leaves that unfurl from the central growing point. These are among the fastest growing plants in cultivation today, and a healthy banana plant will easily grow an inch a week or more, providing it has access to enough water, nutrients, and warmth. Bananas will often remerge from the rhizomes, so when the weather begins to cool, cut your indoor banana off at the soil level (their trunks are soft and easy to cut) and hopefully new shoots will emerge for next season. Indoor bananas are wonderful when used in a large container collection and provide the very essence of the tropics.