Indoor gardening and the keeping of house plants has been documented for thousands of years. Contemporary indoor gardening techniques allow gardeners to keep tropical and sub-tropical plants in very cold climates. Growing houseplants and indoor gardens is a popular hobby in many parts of the world.
Although it may have been practiced earlier, the first written allusion to indoor gardening was in 500 B.C. and referred to the Gardens of Adonis. In later Greek literature, Plato referred to indoor gardening in his book Phaedon. Early indoor gardens relied on mica, or translucent stone. Window glass wasn't developed until around 50 A.D. The development of window glass made indoor gardening easier and more accessible.
One of the earliest documented greenhouses was used to grow cucumbers out of season for the Roman Emperor Tiberius. By the 17th century, greenhouses in Europe were producing exotic fruit like tamarind and oranges. In 1619, a greenhouse in Heidelberg was constructed with a removable roof to hold 340 orange trees. As time went on, heat flues were added to greenhouses and they eventually morphed into the modern hydroponic greenhouse, where fruit and vegetables grow without regard to growing seasons.
Although early greenhouses were developed primarily for the growth of exotic fruits or fruits and vegetables out of season, early horticulturists likely began growing ornamental or biologically interesting plants early on. Since greenhouses were only attainable by the wealthy, they were likely the primary source of early Calla lilies and other exotic African plants grown for study in both the U.S. and Europe.
Many people in the Western world associate bonsai with small, indoor trees. Bonsai is the art of growing miniature trees in pots. The trees are styled to look like larger, weathered trees. Bonsai originated in China during the Han Dynasty (206 B.C.-200 A.D.). It eventually was transmitted to Japan. In both China and Japan, bonsai is traditionally an outdoor art. Trees are grown outdoors, then brought inside for short periods for display. Indoor bonsai cultivation, especially of tropical trees, is a 20th century phenomenon.
The advent of controlled climates and indoor gardens has allowed fruits, flowers, vegetables, and plants normally only available in warm climates to be grown virtually anywhere with a controlled climate and an available window. Indoor house plants and gardening techniques allow orchids from the Amazon to grow effectively in the cold climates of places like Colorado, Minnesota and Illinois. With adequate light, tropical fruit, like oranges and lemons, can grow on miniature trees in a small living room.