Deep Water Culture
Deep Water Culture works on the idea of floating plants on top of the water allowing the roots to hang down into the water. This can be done in a number of ways and this method is one of the more commonly practiced commercial methods.
DWC can be done by floating a foam raft on top of the fish tank, however a more common method is to grow the fish in a fish tank and pump the water through a filtration system and then into long channels where floating rafts filled with plants float on the water surface and extract the nutrients. The water must be filtered before it reaches the channels as particulates and solids in the water will clog up the root systems of the plants and will inhibit their ability to take up oxygen and nutrients.
DWC is the most commonly used method in commercial aquaponics systems as it provides the versatility to grow a relatively wide variety of leafy plants and herbs and can be a set up relatively inexpensively.