CHOOSING A HYDROPONIC SYSTEM Hydroponics systems are classified by the way the nutrient solution is made available to the plant's roots. Aeroponics, DWC, Drip Systems and Ebb & Flow, and NFT Systems are the most common. The Aeroponic system is probably the most technologically advanced of all of the hydroponic systems. Up to a certain point, it is similar to the N.F.T., with nutrients supplied through Humid Air, or as a fine mist. In this system, the roots remain suspended and immersed in a Culture Chamber, or Growing Chamber, where they are sprayed with a mist of nutrient solution at short intervals, usually every few minutes. As in all hydroponic systems, the solution is taken from its supply tank by a pump controlled by an extremely precise timer calibrated for very short irrigating cycles, renging from seconds to minutes. Like the N.F.T system, the aeroponic system is highly susceptible to energy and pump failures. If energy or pump interruptions occur, the plants’ roots will dry extremely quickly resulting in total loss. The spraying of the nutrient solution can be done by medium or high pressure nozzles, by high pressure foggers, by ultra-sonic foggers or even by centrifugal foggers. Another major problem in aeroponic systems is the blocking of the nozzles and high pressure foggers. Not recommended for beginners. DWC or Deep Water Culture is a simple method of plant production by means of suspending the plant roots in a solution of nutrient rich, oxygenated water, with the help of an aquarium air pump. Most people use a 5 gallon bucket or rubbermaid tub with the plant contained in a net pot suspended from the center of the lid and the roots suspended in the nutrient solution. This is great for growing 1 big plant. Very easy to construct and use. Recommended for beginners. The growth rate is amazing. Check this out. This is a 5 week old plant! . Recirculating deep water culture systems (also known as RDWC) use a reservoir to provide water for multiple buckets. Traditional methods using unconnected buckets require individual testing for pH and PPM. . As the water is reintroduced to the bucket it is broken up and aerated with the use of spray nozzles or drip columns. Constant recirculating oxygenates the water and ensures a good mix of nutrients and stabilizes pH throughout the entire system. Testing is therefore only required at one point in the system. Great for growing a lot of big plants. The Drip System is probably the world’s most common hydroponic system. It’s operation is very simple. The nutrient solution is taken out of the container by a pump controlled by a timer, and conducted through tubes and micro-tubes to the base of each plant where it irrigates it drop-by-drop, by means of a small mechanism known as dripper. There are two kinds of drip systems which are normally used:- The Run to Waste System, and the Recirculating System. The run to waste system is an open system, and requires less maintenance work, as the excess nutrient solution is discarded after use, generally by infiltrating them into the sub-soil. Thus, plants are always irrigated with a new fresh solution, so there is no need to constantly monitor the solution’s pH and PPM levels, except when filling the container with a new solution. In the solution-recovery system, which is a closed system, the excesses of nutrient solution are recovered, returned to the container and recycled. This requires a timer of greater precision and is therefore more expensive, in order to obtain very precise irrigating cycles, which is benefitial to the plants. In addition, while recovering the solution, the pH and electrical conductivity levels will always flutuate, requiring more careful control over them. Electrical power failures and pump problems are common with this system, as well as the drippers’ susceptibility to cloging , making daily inspection a must. Drip Systems are the best for large areas. Since the nutrient solution returns to the reservoir at the same rate it is pumped out, you can maintain large growing areas using a relatively small reservoir with less work, and less waste of nutrients and water. Drip irrigation works much like the ebb & flow method, except that the nutrients are moved to and from the plants much more slowly via a dripper. Ebb and Flow Systems fill the growing container with the nutrient solution for a specified period of time, usually 15 min. Then the pump shuts down, which allows the container to drain. These flood systems are especially effective when a SEA OF GREEN method. Flood systems eliminate the need for a dripper for every plant and allow the cuttings to be trans planted. These systems are popular with MJ growers because potted plants may be moved in and out of the system at will. (perpetual harvest) However, this method requires the reservoir to be almost the same size as the growing container. This is one of the easiest systems to use and maintain. Here is a pic of an ebb&flow SOG. NFT - (Nutrient Film Technique) In this system, there is a constant flow of nutrient solution and, because of this, there is no need for a timer to switch on and off the pump that controls it’s circulation.The nutrient solution is pumped from a container to a channel or gully, inside and on the bottom of which the solution flows continuosly in the form of a very thin film in which the roots are partially submerged. The remaining part of the root system is above this thin film in contact with humid air from which they derive their oxygen supply. After running through the whole length of the channel, the remaining nutrient solution returns to the container. With small sized plants, the channel or gully, is usually replaced by a rectangular shaped tube. Normally, in this system, there is no growing medium, and the plants are generally kept upright in germinating pots or nets from which the root system is suspended in the air inside the channels or gullies with their extremities immersed in the solution. The great problem with this system is that an eventual electrical power or pump failure would provoke the interruption of the flow of the film of nutrient solution, causing an extremely rapid drying out and death of the plants. That is why in the design of N.F.T. systems you must consider a backup power supply, like an electrical generator, or a DC powered pump.
