Hydroponic systems can be broadly divided into six different types; though there are hundreds of variations, each one will fall into one of these six categories. These include the wick, water culture, drip, aeroponic, ebb and flow and N.F.T. (nutrient film technique) systems. Provided below is a brief introduction to each of these types which will help you decide which one is the best for your needs.
The simplest among the six is the wick method. This is a completely passive technique in which the growing medium present in a reservoir draws the nutrient solution using a simple wick. The commonly used growing medium includes coconut fiber, Vermiculite, Pro-mix and Perlite. This system works best for a small set up and not when you have large and more number of plants. Among the active systems, the simplest one is water culture method; in this, a Styrofoam platform on which the plants are cultivated floats on top of the nutrient solution. An air pump is attached to the system which blows air into the solution and thus oxygen is supplied to all the plants. This system is the best for growing leaf lettuce but is not advisable for large and long-term crops.
The Ebb and Flow or Flood and Drain system is highly versatile and works well with many types of growth medium. Here the nutrient solution is flooded onto the growth tray and then drained back into the reservoir using a submerged pump. Among all hydroponic systems, the Drip method is most commonly used across the globe. A small drip line is placed beneath each plant and a timer controls the pump so that at regular intervals, the nutrient solution is pumped to the base of each plant. You can draw back the excess solution if you have a recovery system attached to this set up.
In the nutrient film technique, there is a continuous flow of the nutrient solution into the growth tray and the excess keeps getting drained into the reservoir. No growth medium is generally used except for air. The biggest disadvantage of this set up is that the rate of pump failure is high which leads to drying of roots. The aeroponics system is the most sophisticated where the roots are suspended in air which acts as the growth medium and the nutrient solution is sprayed as a mist. All hydroponic systems are useful and work well but it is important that you choose one depending on the kind of crops that you have and also depending on the number.