Hydroponic systems use nutrient solutions instead of traditional soil to grow plants. The roots of the plant rest in the solution, which provides the food the plant needs to grow. There are several different hydroponic systems available.
Nutrient Film System
In a nutrient film system, a small plastic trough is used to hold the plants. The trough is hollow with a covering on top, with small holes for the plants to fit in. Inside the trough flows a constant, thin stream of hydroponic solution that runs along the plants' roots. The nutrient solution is fed through a tube from a reservoir, recycling the nutrient solution through the system.
Aeroponics uses a nutrient solution mist to give the plants food. The plants are suspended above a vaporizer that spreads a nutrient mist throughout the structure. The most popular method of aeroponics is a foam A-frame structure, with the plants suspended in the structure. The vaporizers are placed inside the foam frame, where they spray the roots of the plants.
The aeration system is one of the most simple to make and was the first hydroponics system developed. In this system, a large reservoir, such as an aquarium is used to store the nutrient solution. In a large mesh or foam tray, the plants are placed just above the nutrient solution. Inside the tray is placed vermiculite or pebbles to hold the plants in place. The roots grow down into the nutrient solutions. An air pump and air stone move the nutrient solution throughout the reservoir so that the roots are frequently covered by fresh nutrients.