Aeroponic gardening is a cultivation system for plants which involves suspending them in air and keeping the roots moistened with a mist of nutrient-rich water. As you might imagine, aeroponic gardening is extremely efficient, and commercial agriculture around the world has turned to aeroponics as a potentially profitable way to cultivate plants for a wide range of uses. It is also possible to install aeroponics systems at home, and several manufacturers make smaller systems specifically designed for home use.
When plants are grown aeroponically, no dirt or substrate is used to support them. The plants are allowed to hang free in racks in an enclosed environment which is typically kept somewhat moist so that the plants remain healthy, and nutrients are delivered directly to the roots with aimed spray. The nutrient mix can be adjusted for specific plants, ensuring optimum growth and health, and the plants may be grown with the use of lamps as well, to stimulate rapid, healthy growth and to trick plants into growing out of season.
One of the main advantages to aeroponic gardening is that it is very space efficient, with plants taking up minimal room. Aeroponics systems allow gardeners to stack plants or to arrange them in other novel ways, which can be extremely convenient in limited spaces. Space missions use aeroponics to produce fresh plants for consumption, and these systems could someday be used to support human colonies on other planets or moons.
In the tropics, many plants species grow in the air naturally, as is the case with many rainforest orchids. Human research into aeroponics began in earnest in the 1940s, and by the 1980s, numerous landmark discoveries had been made in the field, making it possible to grow plants cheaply as well as efficiently using aeroponic methods. Aeroponics is also easier on the environment than conventional agriculture, requiring far less water and energy than conventional agriculture or hydroponics, another plant propagation techniques.
Growing plants in air is not without risks. They are still susceptible to diseases which can destroy a crop, for example, as it is difficult to seal an aeroponic space entirely, and in many cases this is not even desired. There has also been some debate about the nutritional mixes used to feed aeroponically grown plants, with some people arguing that highly nutritious water cannot compensate for the complex balance of nutrients in soil.