Hydroponic gardens come in many different varieties. These gardens are typically classified by the hydroponic growth system that is being used. In the paragraphs that follow, you will read a brief explanation of what each of these hydroponic growth systems is. While most moderate hydroponic growth facilities will typically use only one growth system, larger hydroponic facilities may use a number of different growth systems applying specific systems to plants that can benefit from them the most.
Hydroponic systems are characterized as either active or passive. An active hydroponic system moves the nutrient solution throughout the system by using a pump. Passive hydroponic systems rely on the plant’s roots to absorb the nutrients. Hydroponic systems can also be characterized according to whether or not they are recovery or non-recovery. Recovery systems or re-circulating systems reuse their nutrient solution. Non-recovery systems do not collect or reuse their solutions once they are applied to the plant.
The Wick System
The wick system is a passive non-recovery type hydroponic system. It uses no pumps and has no moving parts. As a result the wick system is generally more affordable and easier to maintain than other systems. In the wick system the nutrients are stored in the reservoir and absorbed by the plant through a wick. The nutrient solution travels up the wick and into the root system of the plant. The disadvantage to wick systems is that they tend to keep the growing medium too wet, which doesn’t allow for the optimum amount of oxygen in the root system. Less oxygen means a lower plant yield. As a result the wick system is not the most effective of the hydroponic gardening methods.
The Ebb and Flow System
The ebb and flow hydroponic system is an active recovery type system. In this system a pump is stored under the water in a reservoir and the plants are in an upper tray. The reservoir holds the nutrient solution and the pump. When the pump turns on, the nutrient solution is pumped to the upper tray and to the roots of the plants. Once the water has reached a set level, sometimes called a flood cycle, a pipe allows the nutrient solution to drain back into the reservoir. The process of pumping and draining allows the roots ample oxygen and consequently their nutrient intake is maximized.
Nutrient Film Technique (NFT)
In the nutrient film technique or NFT the system used is an active recovery system. Like the ebb and flow system, submersible pumps recycle the nutrient solutions. The main difference is that in the NFT system, the nutrient solution is pumped into a grow-tube that the roots are suspended into. To get oxygen into the grow tube, capillary matting or air stones are used. The plants are held up by what is called a grow-basket. No growing medium is used in this system, only a nutrient solution.
Continuous Drip
The continuous drip system is an active recovery or non-recovery type system. This system also uses a submersible pump in a reservoir. In the continuous drip system there is a designated drip for each plant. A drip tray is placed under each row of plants so that the collected solution can be sent back to the reservoir. Because there is a drip emitter for each individual plant, any growing medium can be used with this system.
As you have read, different hydroponic growth systems present their own unique advantages and disadvantages. Those who are responsible for the hydroponic growth facilities will carefully weigh their options and consider the optimal growing techniques for the plant types that they intend on producing before making a decision on which system to implement.