Each of these hydroponics styles describe how the nutrient solution is delivered to plants. Nutrient film technique is widely used and is one of the most productive types, although it can be somewhat complex to manage. This is the quintessential image of hydroponics, where a plant is suspended above a channel of flowing nutrient solution with bare roots reaching down into the water. Ebb and flow systems periodically flood the planting trays, allowing roots to absorb as much water and nutrients as they require. After a period of flooding, the water is drained completely, allowing the roots to easily absorb oxygen.
Drip systems provide small amounts of nutrient laden water continuously through tubes with perforations aligned with the placement of individual plants. Deep water culture keeps the plants' roots completely submerged all the time, providing oxygen with a permanent continuous aeration system that pumps bubbles from the bottom of the reservoir. Wicking is an ancient technique with a few modern improvements, but it still has drawbacks and is most suitable fror small plants. In this system, a wick (originally as simple as a short length of string or felt, but perlite or cocoa coir is much preferred) soaks up the nutrient solution, which is then absorbed by the roots. Aeroponics are someone similar to hydroponics, but the plant and roots are suspended entirely above the nutrient reservoir and the solution is delivered by misting the roots on a carefully managed schedule to ensure maximum absorption.
