Monday, May 19, 2008

Deep Water Culture 101

The first commercial hydroponic system I purchased was a Deep Water Culture unit called Emily's Garden. This type of system is what is known as a passive system, as it basically does nothing other than provide an aerated reservoir for the containers to soak in. After using it for sometime I developed a few techniques that the instruction manual did not cover.
Although I have since moved on to using mostly flood and drain systems , I do like the DWC system for swiss chard. When setting up the system I place strips of felt to run from the bottom of the pot to a level that I estimate the bottom of the rockwool cube will be. These felt strips will act as a wick and provide nutrients to the cubes if the level drops too low. The plant with the cube is placed on top of the "wick" and the expanded clay pellets are added to support the plant. When all the containers have been filled I place them in the unit and then dribble the nutrient solution slowly through the containers. By doing so the seedlings are less likely to wilt from transplanting and the system gets off to a good start. Filling the reservoir through the planters also begins the wicking action.
For these small plants I will be using a mild general purpose mixture with a TDS of about 700, and I found that swiss chard likes the pH at 7 or even slightly above.
There are three plants in each container, so I will be growing 18 plants in about six square feet of space. That would be insanity in a soil garden, however, with hydroponic gardening the plant does not have to develop an extensive root system searching for nutrients. All the nutrients the plant needs will be available when it needs them so it can concentrate its energy on growing.

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