The document discusses 6 common hydroponic systems: 1) The wick system uses wicks to passively transport nutrient solution from a reservoir to the growing medium. 2) The water culture system suspends plants directly in nutrient solution with an air stone to oxygenate the roots. 3) The ebb and flow system floods the grow tray with nutrient solution on a timer then drains it back to the reservoir. 4) Drip systems use a timer to drip nutrient solution to individual plants, with recovery systems reusing the excess and non-recovery not recapturing it. 5) Nutrient film technique keeps roots suspended in a constant flowing stream of nutrient solution. 6) Aer

1. Hydroponics Systems<br />Abstract: This article talks about the prominent systems used in hydroponics, each of which share the common soil-less methodology of plant cultivation<br />The word hydroponics originates from the Greek language – hydro meaning water and ponos meaning labor. Hydroponics can therefore be described as a way of cultivating plants, by supplying water mixed mineral nutrition to its roots.<br />The development in hydroponics, both in its use and its systems, has been rather rapid. In fact it is even considered to be a recognized branch of agronomy. In the several countries where hydroponics is used, it has been recognized to be a practical method of horticulture. Primarily, crop yield through hydroponics is considerably high, and secondly, hydroponics can be used in areas where in-ground agriculture is not possible.<br />We proceed now to discuss the various hydroponics systems that are used for plant cultivation. There are basically 6 prominent systems, each varying at least to some degree in which it operates. These systems are the wick system, ebb & flow, water culture, drip, nutrient film technique (NFT), and geoponics.<br />The Wick System<br />The wick system is perhaps the simplest type of hydroponics systems. It is a passive system, which implies that there are no moving parts involved in it. The nutrient solution passes into the growing medium through a reservoir that contains a wick. <br />Among the several growing mediums that can be used with the wick system, the most prominent ones are Perlite, Vermiculite, Pro-Mix, and Coconut Fiber<br />A draw back associated with the wick system is that larger plants may consume a substantial amount of nutrient solution, and a much faster than the wick system can supply.<br />Water Culture<br />Of all active hydroponics systems, the water culture is the simplest one. A Styrofoam platform holds the plant and floats directly on the nutrient solution. Air is supplied to the air stone by an air pump, which causes bubbling in the nutrient solution. This is how oxygen is provided to the roots of the plant. <br />The water culture hydroponics system is very popular with teachers, for a very inexpensive system can be made out of an old aquarium or water tight containers. <br />The water culture hydroponics system is ideal for cultivating leaf lettuce. However, few other plants, especially large or long term plants grow well with this system. <br />Ebb & Flow System<br />The Ebb and Flow hydroponics system temporarily floods the plant grow tray with nutrient solution and then drains the solution back into the reservoir. A submerged pump is usually connected to a timer, which pumps the nutrient solution onto the grow tray. This timer is set to be activated several times a day, depending on the size and type of plant, temperature, humidity and the kind of plant growing medium that is used. The nutrient solution flows back into the reservoir when the timer is switched off. <br />Several different growing media can be used with the ebb & flow hydroponics system. The grow tray can be replenished with gravel or granular Rockwool, or grow rocks. If individual pots are filled with the plant growing medium, it becomes very easy to rotate the plants around or even in and out of the system. <br />The disadvantage associated with the Ebb & Flow system is that some plant growing mediums such as grow rocks and gravel may be susceptible to power outages as well as pump and time failures. As a result, the plant roots can wither if the watering cycles are interrupted. This issue can be somewhat relieved through using growing media such as Rockwool, vermiculite and coconut fiber. These media are capable of storing more water than others.<br />Drip Systems – Recovery / Non-Recovery<br />The most widely used type of hydroponics systems in the world are the drip systems. These are operated using a timer that controls pump submerged in the growing media. When the timer activates the pump, the nutrient solution drips onto the base of each plant.<br />There are two types of drip systems, Recovery Drip and Non- Recovery Drip System. In the Recovery Drip system, the remaining nutrient solution accumulates back into the reservoir and can be reused. In the Non-Recover Drip system, the excess nutrient solution is not collected back into the reservoir<br />Nutrient Film Technique (N.F.T)<br />The most well known of hydroponics systems is the Nutrient Film Technique (N.F.T) system. N.F.T. systems ensure a constant supply of nutrient solution and the submersible pump does require a timer to control it. The nutrient solution pumped into the growing tray, flows over the roots of the plants, and then collects back into the reservoir.<br />In the Nutrient Film Technique, the only growing medium required is air. This system therefore proves to be an inexpensive one. The plant is usually supported in a small plastic basket, and the roots dangle into the nutrient solution. <br />Like the Ebb & Flow system, the N.F.T hydroponics systems are also rather vulnerable to power outages and pump failures, and interruption to the flow of the nutrient solution can cause the roots to dry out.<br />Aeroponic<br />Perhaps the most technical of all hydroponics systems, aeroponics mainly uses air for its operation. The controlling timer runs the pump, moistening the roots of plants with the nutrient solution for a few seconds every couple of minutes. The roots hang in the air, and because of this reason, they are likely to dry out if the moistening cycles are interrupted.<br />