Aeroponic farming is growing plants in air without any substrate or other growing medium. The plants are sustained in place and their roots are sprayed with a “mist” to provide them with the necessary nutrients. The support enters in minimal contact with the plant holding it at the stem with the leaves and crown growing above and the roots hanging free in the air below. If the environment is kept free from pathologies the plants can grow quicker and healthier than they do in soil as the roots are better oxygenated having direct contact with the air.
There are many cases in nature where plants grow like this with air roots under humid conditions, for example orchids have a natural tendency of aerial roots and cling onto other plants and get their nutrients from them. Recent research has shown that a great number of plants can be used to grow in this way and not only the ones with a natural tendency for it.
Potato plants are grown using aeroponics as a means of getting more and same-sized tubers for planting. The method improves productivity as one plant hanging in the air yields up to 20 small potatoes instead of 3 or 4 for with the traditional soil-based method. The roots are normally kept in darkness but are accessible and can easily be harvested in the right moment without moving the plant. The method saves water, not because an aeroponic plant need less of of it, but because all excess water is recycled back to the plants again.
One part of the ongoing preparations and investigation for future space travel to planet Mars is looking into aeroponic growing as part of the survival strategies. The red planet has very adverse conditions indeed with the highest temperatures around -25 °C and the lowest below -100°C and very little water, why growing plants naturally seems out of the question. In one experiment at the Czech University of Life Sciences, the scientists are experimentally growing lettuce, mustard, radishes and herbs using aeroponics, proving that they can survive almost without water.
On the Spanish island of Ibiza one of the first vertical gardens in Europe using aeroponic towers to grow food naturally while saving 95% water in comparison to conventional organic farming. Besides saving water the method also save space and improves crop yields. The tower structures have a separate slot for every plant where the mineral bases nutrients are circulated internally. A great variety of plants are being grown, like tomatoes, cabbage, lettuce and even melons.
Critics to aeroponics argue that, as the plants are fed with artificial nutrients, they don’t have access to the microbiology of healthy soil. In that sense aeroponic farming can be compared to feeding humans directly through an intravenous solution. In that sense, the role of soil is as important as the role of the stomach, to break down organic matter and provide micronutrients and other things that are associated with organic food production. Still, if we want to make a living in such a hostile environment as the red planet, the method seems rather promising.