You have probably heard of hydroponics as it is becoming an increasingly popular way to grow plants. It is a planting technique that allows urban dwellers to grow their own food. However, a similar technique known as aeroponics is not quite as popular. So what is aeroponics?
Aeroponics, which is also known as aerohydroponics, is an alternative to conventional growing techniques. Unlike hydroponics, plants are not grown in an inert growing medium. Instead, are continuously sprayed or misted with water that contains nutrients to help the plants grow.
To understand how an aeroponics system works, it is helpful to compare this method of growing to hydroponics.
Aeroponics vs. Hydroponics
Aeroponics is often considered a type of hydroponics. While hydroponics requires the use of an inert growing medium, plants do not grow in soil or any kind of growing medium in aeroponics. The plants completely rely on the water for nutrients.
So how does an aeroponics system work?
Like hydroponics, seeds are initially grown in an inert medium like Rockwool. Then the seedlings are transferred to a foam “pot” that exposes them to light on one side and mist on the other side. The foam holds the plants in place. The area containing the exposed roots is called the root chamber. The root chamber protects the roots from light exposure and contains the nutrients the plants need to survive. A pump pushes this nutrient solution through a pipe and into a series of nozzles that spray the plants. The nutrient solution that is not absorbed is recycled.
The same types of crops that do well in hydroponic systems will do well with aeroponics. These crops include leafy greens, tomatoes, strawberries, cucumbers, herbs, and cannabis.
Although aeroponics is a bit more complicated than many hydroponic systems, you can still assemble a DIY aeroponics system at home.
Unfortunately, aeroponics can get expensive rather quickly. Unlike many passive hydroponic systems, aeroponic systems require the use of pumps and other devices to automate the spraying. These systems also require a lot of babysitting. If the pumps or some other component breaks, the plants could die rather quickly since they are completely relying on the mist to survive.
Benefits of Aeroponics
Although these systems can get expensive, there are a number of benefits to growing aeroponically. Some of these benefits are explained below.
Extra Oxygen Promotes Root Growth
Roots need oxygen to be healthy. Because the roots are exposed in aeroponics, they have a more plentiful supply of oxygen than they would in a hydroponic system.
Some growers prefer aeroponics because the increased oxygen supply allows the plant to uptake more nutrients and grow faster. The exposure to oxygen also prevents the formation of pathogens.
In 1988, Hillel Soffer and David Burger, researchers from the University of California at Davis, conducted a study to investigate the impact of dissolved oxygen on the growth of Ficus plants and Chrysanthemums. Soffer and Burger compared the rooting of these plants in aero-hydroponics (aeroponics) and conventional soil media.
The rooting percentage, number of roots per rooted cutting, and total root length of the Ficus plants and Chrysanthemums were greater in the aero-hydroponics system than the soil medium. The results of the study indicated that the amount of oxygen affected the timing of rooting, rooting percentage, number of roots, and root length (Soffer and Burger, 1988).
In 1991, these researchers conducted a similar study that found the growth of Chrysanthemum and Ficus plants in aero-hydroponics was reduced as the dissolved O2 concentration decreased (Soffer et al. 1991).
Efficient Water Use
Aeroponic systems also use water much more efficiently than conventional growing techniques. This is because aeroponic systems are closed and recycle water after misting. According to a study conducted by NASA, aeroponics reduces water consumption by as much as 98 percent.
Ability to Grow in Small Spaces
Like hydroponics, aeroponics provides people the opportunity to grow food in small spaces. People living in apartments or in urban settings can use aeroponics to grow their own food.
Higher Yields
Like hydroponics and aquaponics, aeroponic systems can also produce a higher yield of crops. This is because the plants are able to grow faster due to the nutrient solution. Unlike conventional growing techniques, these alternative growing techniques (e.g., hydroponics, aeroponics, and aquaponics) give the grower a lot of control. As a result, you can create a nearly ideal environment for growing plants. This, in turn, results in higher yields.
Research has backed up this claim. For example, a study conducted at the University of Mississippi in 2013 compared the product yield, total phenolics, total flavonoids, and antioxidant properties of different leafy vegetables, herbs, and fruit crops (Chandra et al. 2014).
The study found that, in general, the plants grown in the aeroponic system had a higher yield and comparable phenolics, flavonoids, and antioxidant properties as compared to those grown in the soil (Chandra et al. 2014). The following table lists the increase in yield by crop.
| Crop | Percent increase in yield compared to conventional soil |
|---|---|
| Basil | 19% |
| Chard | 8% |
| Red Kale | 65% |
| Parsley | 21% |
| Bell Pepper | 53% |
| Cherry Tomatoes | 35% |
| Cucumber | 7% |
| Squash | 50% |
DIY Aeroponic System
Now that you have learned more about aeroponics, let’s talk about how you can build your own system.
High-Pressure vs. Low-Pressure
Aeroponic systems are typically classified as high-pressure or low-pressure.
Low-Pressure Aeroponics (LPA) is also referred to as soakponics. In LPA, plants are suspended in a root chamber, and plastic nozzles are used to spray the roots with a nutrient solution. You can use a submersible fountain pump for LPA.
In contrast, High-Pressure Aeroponics (HPA) sprays nutrients through a nozzle that will produce a droplet size between 20 and 50 micrometers (0.02 to 0.05 millimeters). In order to produce droplets that small, you will need a diaphragm pump that is rated for pressures between 60 and 150 psi.
Plants grown in HPA typically grow faster. The finer mist promotes more nutrient uptake than sprays consisting of larger droplets.
However, HPA systems are very expensive. Because the nozzles are so small, they are prone to clogging. For homeowners and DIY gardeners just getting into aeroponics, I suggest starting with an LPA system.
Here is a very thorough video I found that walks you through the process of making your own LPA system.
Aeroponics Board
An aeroponics board is a system where plants grow above the board. Below the board, nozzles spray the roots with a nutrient solution. A small pump is used to deliver the nutrient solution to the nozzles.
Aeroponics Triangle
Another type of aeroponics system involves creating an enclosed space by constructing a triangle from polystyrene boards. This triangle formation results in a relative humidity of 100% and plenty of oxygen availability.
Researchers have used this type of construction in their studies. For example, Leoni et al. (1994) used this type of construction when studying how well cherry tomatoes grow in aeroponics.
An aeroponics system can also be constructed a tall cones made of PVC frames and enclosed with chicken wire and plastic. The roots hang at a downward angle inside the cone, and the plant vegetation grows upward through the plastic on the side.
Vertical Tower
Finally, aeroponics systems can be constructed as a tower. You can purchase kits like this one online.
However, you can make your own vertical tower from 5-gallon buckets, PVC pipes, or even clay pots.