Hydroponics is a way of cultivating plants, by providing nutrients that they need to grow in water. Although no soil is used, a medium may be used for the roots to soak and provide constant water supply. Such mediums lead us to think about hydroponics systems, which are discussed below.
Basically there are 6 types of hydroponics systems, including wick, water culture, ebb & flow (also known as flood & drain), drip, nutrient film technique (NFT), and aeroponic. Although there are many variations on these 6 systems, all hydroponics methods are a combination these 6.
The Wick System
By far the simplest type of system, the wick system is a passive hydroponics system, meaning that there are no moving parts in it. The nutrient solution is getting drawn into the growing medium from a reservoir with a wick.
The wick system is able to use several plant growing mediums such as Perlite, Vermiculite, Pro-Mix, and Coconut Fiber- all of these being the most popular.
There is a disadvantage associated with the wick system, which is that the plants are large or the nutrient solution may use up a lot of water, much quicker than the wick system can supply it.
Water Culture
Of all active hydroponics systems, the water culture is the simplest one. A Styrofoam system is the platform that holds the plant and floats directly on the nutrient solution. Air is supplied to the air stone by an air pump, and bubbles are so caused to the nutrient solution, providing oxygen to the roots of the plant.
The water culture hydroponics system is ideal for cultivating leaf lettuce, given the fact that these grow rather fast through this system. However, few other plans grow well with the water culture hydroponics system.
Additionally, the water culture hydroponics system is very popular with teachers, for a very inexpensive system that can be made out of an old aquarium or water tight containers.
The biggest disadvantage of the water culture hydroponics system is that it does not suit large or long term plants.
Ebb & Flow System
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 in this system. The timer pumps the nutrient solution onto the grow tray. The nutrient solution flows back into the reservoir when the time is turned off. It 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 Ebb & Flow hydroponics system can be used with several plant growing mediums. The grow tray can be filled with gravel or granular Rockwool, or grow rocks. If individual pots are filled with the plant growing medium, it is easier to move the plants around or even in and out of the system.
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. Consequently, the plant roots can dry out quickly when the watering cycles are interrupted. This issue can be addressed somewhat though through growing media that store more water, such as can be relieved by using growing media that keeps more water, such as Rockwool, vermiculite and coconut fiber.
Drip Systems – Recovery / Non-Recovery
The most widely used type of hydroponics systems in the world are the drip systems. They are easier to operate, and a timer controls a submerged pump. When the timer activates the pump, the nutrient solution drips onto the base of each plant by a small drip line.
There are two types of drip systems, Recovery Drip and Non-Recovery Drip System. In the Recovery Drip system, the left over nutrient solution is accumulated back into the reservoir for re-use, whereas in the Non-Recover Drip system, the excess nutrient solution is not collected back into the reservoir. In the recovery drip system, therefore, the timer is inexpensive and efficient since it does not require an accurate control of the watering cycle. On the other hand, the non-recovery drip system requires a precise timer in order that the watering cycles can be adjusted for the plants to get a sufficient amount of nutrient solution and there is less waste of the solution. This also means, then, less maintenance is required of the non-recovery system, whereas the recovery system can have large shifts in the nutrient strength levels routinely need checking and adjusting.
Nutrient Film Technique (NFT)
The most known of hydroponics systems is the Nutrient Film Technique (NFT) system. NFT systems entail a continuous supply of nutrient solution and the submersible pump requires no timer. The nutrient solution pumped into the growing tray, flows over the roots of the plants, and then collections back into the reservoir.
In the Nutrient Film Technique, there is generally no growing medium needed other than air. This proves to be an inexpensive system, therefore, since there is no need of replacing the growing medium. The plant is usually supported in a small plastic basket, and the roots dangle into the nutrient solution.
The NFT hydroponics systems is rather vulnerable to power outages and pump failures, and interference to the flow of the nutrient solution causes the roots to dry out.
Aeroponic
Perhaps the most technical of hydroponics systems, the aeroponics systems mainly uses air to function. The roots hang in the air and receive moisture from the nutrient solution. The moistening occurs every few minutes, but because the roots hang in the air (like in the NFT system), they dry out if the moistening cycles are disrupted. In the Aeroponic hydroponics systems, the controlling timer runs the pump for a few seconds every couple of minutes.