Ebb And Flow Systems

There are a number of methods that are used in growing hydroponic plants and providing nutrients to their roots. One method is the continuous flow system. In this system a film of nutrient is pumped into the growing tray and it is the tray which is sloped so that it drains of at the other end and is sent back to the solution reservoir. By using this method the plants receive a continuous flow of nutrients. So the plant can feed whenever they want as the supply of nutrient is always available. However as a steady power supply is required to keep the solution pumping into the growing trays the plants can die if there is a long power outage or a pump failure. Also as the solution is being recycled there is the possibility of bacteria and pests invading the solution and the plants and destroying them.

A second method is the ebb and flow system. In this system the growing tray is placed on a container into which the nutrient solution is pumped. Once the tray is full the pump stops pumping and the nutrient solution slowly flows back or is pumped back into the nutrient reservoir tank. This pumping and draining needs to be done depending on the number of times the solution is to be pumped into the grow tray. For this a timer may be used. The hazard of providing nutrients using this method is that in case the timer fails or is faulty and should the pump develop a problem the entire process would grind to a halt and the plants would die. The other problem of using this method is that the solution may carry bacteria or pests to the roots.

First of all a tray is required which will hold the plant growing tray. A deep plastic tray or trough would do very well. Plastic is preferred over metal or wood as metal would tend to rust with continuous use and the wood may start to rot. The tray should be painted black so that light does not penetrate through it. Next one would require a reservoir which could be a large plastic bucket or even a plastic trash can would do. A pump and timer would be required to pump the nutrient solution from the reservoir into the growing tray. The pump should be a reversible pump and its size really would depend on the amount of pumping it would be required to do. Once the tray is full it pumps the solution back into the reservoir. It is preferred that the growing tray has an over flow tube so as to prevent any excess solution getting pumped into the tray. Any excess solution would automatically flow back into the reservoir. This may happen should the timer fail. A tube from the reservoir to the pump and from the pump to the growing tray would be required. If a plastic pipe is used one must make sure not to use a transparent tube as algae could grow in it which would eventually affect the plants roots and destroy them.

One must make sure that the timer or pump in this method does not fail as this could have disastrous results. If one chooses to use this method then the choice of the growing medium also plays an important role as those mediums that do not have high retention would dry out quickly in case of a power outage and causes the plants to die. In this method the preferred substrate or growing medium would be rockwool, vermiculite or coconut fiber as all three have high water retention.