Indoor spaces, especially large ones, often feel better with indoor trees to liven up the space and bring in the feeling of the outdoors. In areas of inclement weather where delicate tree species may not do well outdoors, these trees are an excellent option, especially during gloomy winters. A wide range of trees are suitable for indoor growing if they are well cared for, and they have varying levels of light requirements, meaning that an indoor tree can be found for most spaces with a little bit of searching at local garden stores.
If you have an atrium or greenhouse, your options for indoor trees will be greatly expanded, because of the larger amount of natural light. In addition, these spaces are specifically designed for the display of plants, so it is possible to build an indoor jungle with controlled humidity and warmth. If the tree is being placed in a multi-purpose room such as a living room or office, your options will be more limited by the space, although there are still numerous choices.
Some popular indoor trees include ficus, citrus, dracena, palms, coffee trees, and African pine trees. For people with smaller spaces, bonsai is a tree which takes up minimal space, and bonsai trees in ranging sizes from versions designed to live on a desk to small shrubs can be obtained. In all cases, the size of the tree can be limited by the pot it is grown in, so if you do not want it reaching a dizzying height, restrict it by repotting it infrequently. Many indoor trees also like higher levels of humidity; a cheap and attractive way to increase humidity is to fill a dish with stones and cover it with water.
The ficus is a classic indoor tree, and there are a number of types of ficus to choose from including the weeping fig and fiddle leaf fig. When ficus is stressed, it will lose its leaves, which can be messy but is not harmful to the plant. To avoid leaf loss, keep ficus humid and in an area of bright, but indirect, light. In addition, try to refrain from moving a ficus, and let it dry out completely between waterings.
Citrus trees also do well indoors, as long as they are provided with at least four hours of direct sunlight each day. A citrus tree can be kept in a breakfast room or on an enclosed porch with plenty of light, or it can be moved to take advantage of the sunshine. Citrus trees smell good and will produce fruit, and they prefer to be kept moist and in relatively humid conditions. Dracena, or dragon tree, comes in a number of species as well, but generally has long, thin leaves and it can grow quite tall. Dracena also enjoys darker spaces, making it a good choice for dim rooms.
For a touch of the exotic, you may want to consider using a palm, African pine, or coffee plant as an indoor tree. These plants are quite hardy and accept varying levels of light. If given large pots to grow in, they will also get quite sizable. The coffee tree will also produce coffee fruits, which can make it an interesting conversation piece as well as a pretty indoor tree.