In water culture systems the plants are placed such that their leaves are bathed in the nutrient solution within the holding tank.
In a floating ( sometimes called a ‘Raceway system’) like the one opposite the nutrient holding tank is actually the growing bed. The plants themselves are placed into holes on floating styrofoam boards with their roots dangling into the nutrient solution.
The solution itself rather than being pumped around as in the other systems, Is oxygenated and moved around the plant roots by an aquarium type air pump attached to a perforated tube at the bottom of the holding tank, Which continuously blows air bubbles into the nutrient solution.
Plants which seem to enjoy living in this system are leafy plants such as Luttuce, Spinach, Chard etc.
Unlike the other systems here the pump must be run continously to oxygenate the nutrients.
I am regularly using this system each year now successfully along side my main hydroponics systems to grow batches of lettuces. To see what my water culture system looks like have a look at the Greenhouse No 2 page.
The dripper feed system or drip irrigation system makes it easy to treat each plant individually with regards to the amount of nutrient solution each receives.
The nutrient solution is pumped up from the holding tank along pipes to drippers, These hang over the plants or are inserted into plant pots or blocks of rockwool as in the animation opposite.
The dripper itself is fitted to limit the flow from the pipe to the plant to just a mere drip. The plant will take what it needs and any excess solution is allowed to drain back into the holding tank ready for re-use.
Like the NFT system it is not necessary to run the pump throughout the night.
I have tried this system out myself during the 2002 season and although it work
ed succesfully I am now using the tank and pump for a plain NFT setup. Partly because I didn’t see any increase in production over growing with the NFT Method and Partly because of the extra work necessary in setting the system up and keeping it working (ie. the drippers kept getting blocked for me)