Types of Hydroponics:
Deep water Culture:
The deep water culture system is the simplest of all active hydroponic systems. In a deep water culture system, the roots are suspended in a nutrient solution. An aquarium air pump oxygenates the nutrient solution, this prevents the roots of the plants from drowning. The primary benefit of using this system is that drippers/emitters remain free from clogging.
The platform that holds the plants is usually made of Styrofoam and floats directly on the nutrient solution. This system is best for fast growing water loving plants such as lettuce. Very few plants other than lettuce will do well in this type of system. The biggest disadvantage of this kind of system is that it doesn’t work well with large plants and long-term plants.
Nutrient Film Technique:
This is a type of hydroponic system, where a continuous flow of nutrient solution runs over the plants roots. This type of system works very well since only the tips of the roots come in contact with the nutrient solution, the plant is able to get more oxygen which facilitates a faster rate of growth.
The nutrient solution is pumped into the growing tray (usually a tube) and flows over the roots of the plants, and then drains back into the reservoir. There is usually no growing medium used other than air, which saves the cost of replacing the growing medium after every crop. This system is very susceptible to power outages and pump failures. The roots dry out very rapidly when the flow of nutrient solution is interrupted.
In this method the roots are misted with a nutrient solution while remaining suspended in the air. There are two primary methods to get the solution to the exposed roots. The first method involves a fine spray nozzle to mist the roots and the second method uses a fogger. It is probably the most high-tech type of hydroponic gardening.
Like the nutrient film technique system, the growing medium is primarily air. The roots hang in the air and are misted with nutrient solution. The misting are usually done every few minutes. Because the roots will dry out rapidly if the misting cycles are interrupted. This system needs a short cycle timer that runs the pump for a few seconds every couple of minutes.
It is one of the easiest and lowest costing method. In this method a material is surrounded by a growing medium with one end of the wick material placed in the nutrient solution. The solution is then wicked to the roots of the plant. This system can be simplified by removing the wick material all together and just using a medium that has the ability to wick nutrients to the roots. This works by suspending the bottom of your medium directly in the solution.
Perlite or vermiculite must be used as medium. Mediums such as rock wool, coconut coir, or peat moss must be avoided because they absorb too much of nutrient solution which can suffocate the plant. This is a passive system that means there are no moving parts. The nutrient solution is drawn into the growing medium from the reservoir with a wick. The biggest drawback of this system is that plants that are large or use large amounts of water may use up the nutrient solution faster than the wicks can supply it.
Ebb & Flow:
It is also known as a flood and drain system. This type of system functions by flooding the growing area with the nutrient solution at specific intervals. The nutrient solution then slowly drains back into the reservoir. The pump is hooked to a timer, so the process repeats itself at specific intervals so that the plants get the desired amount of nutrients. This action is normally done with a submerged pump that is connected to a timer.
It is ideal for plants that are sensitive to periods of dryness. It is a versatile system that can be used with a variety of growing mediums. The main disadvantage of this type of system is that with some types of growing medium such as gravel, grow rocks, perlite, there is susceptibility to power outages as well as pump and timer failures. The roots can dry out quickly when the watering cycles are interrupted. This problem can be solved somewhat by using growing media that retains more water such as rock wool, vermiculite, coconut fiber or a good soilless mix.