Using a prototype lunar greenhouse, researchers from the University of Arizona has demonstrated that plants can be grown without soil.
An 18-foot long tube that contains water-cooled sodium vapor lamps and “envelopes” to hold the seeds, the lunar greenhouse (or something similar) could one day supply food to astronauts on the moon or Mars. It could be essential for colonizing the moon — which has no atmosphere, no natural water and has extreme temperatures.
The said lunar greenhouse works by by feeding carbon dioxide into the greenhouse through pressurized tanks. In a lunar base astronauts would carbon dioxide by breathing while water for the plants could be extracted from their urine. Sunlight on the other hand, could be channeled to the underground plants through fiber optic cables.
According to the Arizona researchers, led by Gene Giacomelli:
The system contains about 100 kilograms of wet plant material that can provide 53 quarts of drinkable water and a small amount of oxygen during a 24-hour period, while consuming about 100 kilowatts of electricity and half a kilogram of carbon dioxide. It can even be collapsed into a four-foot wide disk for interplanetary travel and deployed in less than ten minutes.