Deep Water Culture (DWC) Method
This is a hydroponic method of plant production by means of suspending the plant roots in a solution of nutrient-rich, oxygenated water. A very simple method for the home enthusiast. Kratky method with an air stone and pump.
Deep Water Culture – (DWD) for the Hobbyist
Most hobby growers use Deep Water Culture (DWC). Net pots, plastic pots with netting to allow roots to grow through their surface, are filled with a hydroponic medium such as Hydroton or Rockwool to hold the base of the plant. In some cases net pots are not needed. For Oxygenation of the hydroponic solution, an air stone is added. This air stone is then connected to an airline that runs to an air pump.
As the plant grows, the root mass stretches through the rockwool or hydroton into the water below. Under ideal growing conditions, plants are able to grow a root mass that almost fills the entire container in a loosely packed mass. As the plant grows and consumes nutrients the pH and EC of the water fluctuate. For this reason, frequent monitoring of the nutrient solution must take place to ensure that it remains in the proper range for the crop.
A pH that is too high or too low will make certain nutrients unavailable for uptake by your plants. Generally, the best pH for hydroponic crops is between 5.5-6.5. In terms of EC, too low means that there is a low salt content, usually meaning a lack of fertilizer, and an EC that is too high indicates a salt content that could damage the roots of your crops. Desired EC depends on the crop that you are growing. A common EC for leafy greens is somewhere between 1.5-2.2.
Recirculating Deep Water Culture – (RWDC)
Traditional methods using unconnected buckets require each bucket to be tested for pH and conductivity factor (CF) individually. This has led to the creation of Recirculating Deep Water Culture (RDWC) systems. Rather than having individual buckets, RDWC containers are linked together. The most common way to do this to use PVC pipe.
A pump is also added at the front of the system. This pulls water through a line from the rear of the system into a control bucket. This return line generally has a filter on it that cleans any larger chunks from the water before it reaches the pump. The individual containers, including the control, are aerated.
The main disadvantage of RDWC is that disease can spread quickly in these systems. The recirculation of the water can facilitate the transfer of disease and fungus from one reservoir to another.
This article is excerpted from Wikipedia. To read the article in its entirety click HERE.
Here is a video animation of building a RDWC system Animation