Aeroponics is specifically designed in order to maximize the amount of oxygen exposure that each plant receives. Therefore, plants are often suspended in mid-air to enhance exposure even further. High levels of oxygen stimulate a plant’s growth, meaning they grow even faster than they would if buried within soil. Aeroponically grown plants are more likely to grow faster and healthier. Some studies have shown that crop yields in aeroponics can be ten times that of their soil-bound relatives. Healthier plants, and more of them, is the goal for any entrepreneurial farmer.
Aeroponics requires no growing media. Plain baskets or foam plugs can be used to firmly suspend the plants while maintaining their integrity. Oftentimes, these are found in small holes atop a growing chamber which contains a reservoir of water. Here, the water is compressed and mixed with essential nutrients to form the healthy mist that will be used on the plants. Regular, nutrient rich spray means the plants always have the food and water that they need.
These growing chambers are airtight and light-proof, protecting the root zone and preventing algae growth. Oxygen should be able to reach the plants, but pests and water must be kept out. The materials used must also be able to handle the near-constant moisture found within an aeroponic design. Typically, an aeroponics system includes the following features:
- A submersible pump to transport water from the reservoir to the sprinklers
- Sprinkler heads or misters to apply the mist
- A storage container to contain the plant’s root zones and the reservoir of water
- Supports for the plants’ stems themselves
- Pipes and tubing to transport nutrient solution
- A timer for intermittent watering cycles
The most important differentiating factor between styles of aeroponics has to do with the water droplet size. Based on the size of the water droplets found within the mist, aeroponic systems can be divided into several categories:
Low Pressure Aeroponics
This is the most common form of aeroponics found today. Low pressure systems rely on a simple pump, like those found in a basic fountain. This is a simplistic and low-investment design, sometimes referred to as “soakaponics.” This is because low-pressure misters are only capable of producing a light spray, rather than true fine mist. Therefore, most DIY designs will end up essentially being soakaponic designs.
Due to their low level of initial investment and easy set-up, low pressure aeroponics systems are becoming increasingly popular. In place of the expensive equipment that comes with true atomization, all that's needed are simple, low-pressure sprinklers.
Water fountains and pond pumps are perfectly suited to low pressure aquaponics. As each sprinkler head is added, the PSI in the system drops. Usually, fountain and pond pumps don't advertise their PSI rating. However, the more GPH the pump can handle, the better. The higher the head height, the more pressure there will be, but this will need to be taken into consideration when designing your reservoir.
Sprinkler heads should overlap to cover the entire root zone as your plants and their roots grow. If the roots of a particular plant are particularly thick, spray from sprinkler heads may not penetrate fully. The sprinklers should be installed above the roots in this design, so that the water drips down through the root zone gradually, rather than dripping quickly off the bottom. Too much moisture can lead to root rot. Each additional sprinkler head will reduce the pressure, so it’s essential to use the minimum number of sprayers possible while still ensuring adequate moisture.
High Pressure Aeroponics
With a true mist, we can deliver moisture into the air and nutrients to root zones more effectively. However, there must be enough pressure in order to create a true mist, which is beyond the capacity of an ordinary fountain pump. Aeroponics at high pressure works with a pressurized water tank with a pressure of up to 90 psi, accompanied by high quality sprinklers and misters. This fine mist provides more oxygen than a low-pressure system would, but the system can be more expensive to set up and install.
Typically, a high-pressure aquaponics system requires the following:
- A pressurized reservoir tank
- This is where the nutrient solution and water is stored. This system is a close loop, so run-off is collected and dropped back into the reservoir to be resprayed.
- A valve in order to open and close the lines attached to the mister
- A cycle timer to open and close the above valve
- This is used to control the amount of water moving into the reservoir. Oftentimes, growers have the best success with a one minute on/five minutes off nebulizer, and others have had success with 15 second fogging periods.
- Fine spray mist heads
- The smaller the drops of water, the better plants can absorb them.
- A small air compressor to pressurize the reservoir tank
- Enclosed growing chamber for the roots
- A collection method for runoff
Although the basic design of a high-pressure growing chamber will remain the same as that of their low-pressure relatives, the way in which the water and nutrient solution are delivered will need to be altered. A water pump would need to be turned on and off from hundreds to thousands a time a day in order to maintain the necessary pressure. Unlike low pressure systems, high pressure systems do not require pumps and instead use a dual chamber tank to pressurize the reservoir. Nutrient-rich water is stored on one side, while compressed air is stored on the other. Once the air reaches the proper pressure, between 60 and 90 psi, it is pressed against the dividing diaphragm until the reservoir side reaches the same pressure.
Within the growth chamber, pipes or tubing connect the reservoir to the sprinkler heads. A cycle timer controls the valve, which opens and closes water flow. This on/off cycle is used continuously throughout the day to keep the roots from drying out.
Ultrasonic Fogger Aeroponics
To atomize the water, Fogponics uses an ultrasonic fogger. High-frequency vibrations are used by ultrasonic foggers to break up water into its component atoms, which we view as fog. When it comes to plant uptake, these tiny droplets of water are highly powerful.
When operating an ultrasonic fogger, there are a few things to keep in mind. The fog or mist produced by the fogger may build along the container's bottom, making it difficult to always keep roots appropriately wet. Mineral buildup can cause plates or other machinery to clog. Wipe down the apparatus with white vinegar to address the problem.
