Aeroponics, similar to hydroponics, uses now growing medium. Sometimes growers place a closed cell foam around the stem. This allows for plugging of the root chamber and not allowing for contamination or air escape. The roots of the plants are suspend in a dark chamber that receives no light. The rooting chamber is air and water tight in which a nutrient solution is sprayed. This process is the most efficient in growing, energy uses.
Aeroponics is comprised of two watering systems. They are calling misting or fogging. Both of these systems have the roots of the plants suspended in a closed or semi closed environment. Because the roots are unburied, they are allowed access to oxygen almost all the time. Only certain plants have greater harvesting potentials. Plants from cuttings, lettuces, strawberries and herbs are most popular.
Droplet size is key to aeroponics. In misting and fogging systems use microns to measure the size of released solution. Large droplets pose a problem by restricting oxygen to the roots. Small droplets or fine droplets produces solutions that can stick to roots better, and allow roots to absorb nutrients as well. Water pressure droplet size is measured at 5-50 micrometers.
Another factor of effectiveness of aeroponics is the frequency of watering done. Some plants require constant watering. There plants will receive larger droplets are used. Leave surfaces could wilt, and mold under the constant mist. Sometimes shallow pools are collected at the bottom of the rooting chamber.