6 Types of Hydroponic Systems
1. Passive Systems
Wick systems are by far the simplest type of hydroponic system. These are so-called wick systems where no pump is used and the process works on the capillary effect. To explain: a wick is immersed at one end into a container with nutrient solution, which is automatically absorbed and passes through to the other end of the wick, which leads into the root container. It is particularly suitable for soil substrates and for most very slow-growing houseplants or even trees. Thanks to the wick, constant moisture is maintained and the mentioned types of plants can be safely left for two to three weeks without supervision and any care. However, be careful with large plants or those that use larger amounts of water. For those, the wick might not supply sufficient moisture.
2. Water Culture
Deep Water Cultivation (DWC) is the name for the classic system used in botanical laboratories. The water culture system is the simplest of all active hydroponic systems. A platform that holds perforated pots with plants in its openings is usually made of foam polystyrene and floats directly on the surface of the nutrient solution. At the bottom there is an air stone (used in aquariums) connected to a small air pump that delivers air to the air stone. This bubbles the nutrient solution and supplies oxygen to the plant roots. A problem with this system can occur when the air pump fails.
3. Flood and Drain Method
Ebb & Flow (Flood and drain) is a classic, very simple and reliable hydroponic system that irrigates plants at timed intervals. Plants are typically arranged in individual containers filled with growing medium of your choice in a flood tray (containers of any size can be used).
Unlike deep water culture, flood and drain systems do not keep plant roots permanently suspended in nutrient solution. Instead, the growing reservoir is temporarily flooded with nutrient solution and then the solution is drained back into the tank. This action is usually performed using a submersible pump connected to a timer. Once the timer turns on the pump, the nutrient solution is pumped into the growing reservoir. When the timer turns off the pump, the nutrient solution flows back into the tank. The timer operation is set depending on the size and type of plants, ambient temperature and humidity, and the type of growing medium used.
This irrigation method delivers food and moisture to the root systems in specific doses. When the flood tray is dry, the roots have a chance to absorb oxygen, ensuring they don't become waterlogged.
The system includes a simple pump, irrigation tubing and a drainage valve. The ready-made system is filled with growing medium.
This system can experience problems during long-term power outages, when root drying may occur.
4. Drip Irrigation Systems
Top drip systems are probably the most widespread type of hydroponic system in the world. Operation is simple, a timer controls a submersible pump. The timer turns on the pump and nutrient solution is supplied to individual tubes that feed the plants individually through gradual dripping of the nutrient solution. In a recovery drip system, excess nutrient solution is collected back into the reservoir for reuse. In a non-recovery system, the solution is not collected for reuse.
A recovery drip system uses nutrient solution much more efficiently because excess solutions are reused, which also allows the use of a cheaper timer, as the recovery system does not require precise control of irrigation cycles. Conversely, a non-recovery system must have a more precise timer to allow adjustment of irrigation cycles to ensure that plants receive sufficient nutrient solution and that runoff is kept to a minimum.
A non-recovery drip system does not require as much maintenance as a recovery system because excess nutrient solution is not recycled back into the tank. Therefore, the nutrient strength and pH of the reservoir will not change. This means the reservoir can be topped up with pH-adjusted nutrient solution and then forgotten until you need to mix more. A recovery system can have large changes in pH and nutrient values, which then require regular checking and adjustment.
5. Nutrient Film Technique
Nutrient Film Technique (N.F.T.) is the type of hydroponic system that most people think of when considering hydroponics. Here, nutrient solution is supplied by a submersible pump from the reservoir to the growing container, where it creates a shallow and slowly flowing layer. The nutrient solution flows over the plant roots and is then drained back into the tank.
One of the main advantages of NFT is perfect oxygenation due to the fact that the nutrient solution is evenly distributed over the entire surface of the growing container, because the container slope is set at 2-3%. The reaction between nutrient solution and air thus occurs over the entire surface. With this method, there is perfect oxygenation of the entire layer, and therefore the plants. System installation is easy and can be assembled from almost anything the grower has at hand.
6. Aeroponic Systems
Transform the nutrient solution into mist using an ultrasonic membrane. A so-called dry mist forms in the air – the droplets have a diameter of approximately 2.5 microns, so humans cannot perceive them as moisture. In aeroponics, plants receive water and nutrients from the air. Some aeroponic systems are specially adapted for indoor growing.