What is hydroponic farming?
Hydroponic farming in short
Hydroponic farming, also referred to as hydroponics or hydroponic cultivation, is a type of horticulture in which plants are grown without soil. Instead of using soil, hydroponics grows plants by exposing their roots directly to a nutrient-rich water solution. This allows the plants to absorb all the required nutrients directly from the water, while normally they would be absorbed through the soil in which they grow in.
The goal in hydroponics is to optimize plant growth by supplying the ideal amount of nutrients to the plants, maximizing the growth and quality of the final product. This growth is often further optimized by controlling a range of other growth critical variables like the light, the temperature, aeration, CO2 concentration as well as the relative humidity of the system.
Different hydroponic farming systems
There are many different types of hydroponic systems available and these systems come in a number of different configurations. First way to categorize these configurations is to determine whether the system is open or closed. Open systems drain the nutrient solution after each application while closed systems recycle all excess water inside the system. These closed systems are also referred to as closed-loop systems.
The second way to categorize of hydroponic systems is based on the type of culture used. The two common culture systems are liquid culture and aggregate culture. In liquid culture systems, roots hang inside a growth chamber being directly in contact with a nutrient solution (either being misted by the solution or being submerged in the solution). On the other hand, aggregate culture systems use a range of inert medias to support the plants’ roots. In these systems, the media itself can be irrigated but it can also be used to direct the solution into the roots.
The next categorization for hydroponic systems is based on the number of vertical planes of production being used. A single plane production uses a single horizontal plane to produce plants. This is most common in large hydroponic greenhouses. Vertical plane production is a method of farming in multiple planes or tiers and it is widely used especially in indoor farming due to its ability to utilise all 3D-space more efficiently. We talk more about the different types of vertical farming in the next section.
Most common hydroponic techniques
There are many different types of hydroponic systems available but the most common techniques are:
Aeroponics
Aeroponics is a type of hydroponics where the nutrient solution is distributed to the plants’ root system using a fine mist. The plants’ roots are suspended in the air and they absorb the water and nutrients from the ambient humidity. Aeroponics is also the technique used in all Arctic Farming farming modules.
Aquaponics
Aquaponics is a combination of hydroponics and aquaculture (the farming of aquatic species). Aquaponics circulates water to the growth system to and from tanks that are actively being fertilized by fish or other aquatic species.
Nutrient Film Technique (NFT)
In Nutrient Film Technique (NFT), the plant’s roots lay inside inclined troughs with a thin film of nutrient solution flowing through them. This is a common technique especially for greenhouse hydroponics.
Deep Water Culture (DWC)
In Deep Water Culture (DWC), plants’ roots are fully submerged in a nutrient solution with the plants resting on top of a raft, or a lid.
Wick System
Wick Systems uses an aggregate medium and an absorbent wicking material submerged in the nutrient solution. The wick material absorbs the solution up into the medium and into the plant’s roots zone.
Ebb And Flow
Ebb and Flow systems use a growing tray and an aggregate medium, a nutrient tank (often called a sump) and a pump with a timer. Ebb and Flow periodically flood the growth tray with the nutrient solution, with all excess water being drained back into the sump. Ebb and Flow is commonly used in basic seedling systems.
Drip System
Finally, a Drip System delivers the nutrient solution to each plant using irrigation lines and individual emitters that literally drip the solution into each plant’s root zones one droplet at a time.
Source: NoSoilSolutions. https://www.nosoilsolutions.com/6-different-types-hydroponic-systems/
Vertical farming
Vertical farming is a type of hydroponic farming that grows plants vertically. Instead of using just a single horizontal plane of production, and maximizing the production per square meter (as in conventional farming or in a hydroponic greenhouse), vertical farming utilizes both the horizontal and vertical planes in order to maximize production per cubic meter.
There are a number of different ways to build a vertical farming system. These methods have been best summarized by Beacham, Vickers and Monaghan (2019) in their article Vertical farming: a summary of approaches to growing skywards in which they divide vertical farming methods into six categories. These designs are visualized in the figure below.
Source: Beacham, A. M., Vickers L. H., & Monaghan, J. M. (2019) Vertical farming: a summary of approaches to growing skywards. The Journal of Horticultural Science and Biotechnology, 94(3), pp. 277-283.
Stacked systems use a number of horizontal tiers stacked on top of each other. These tiers can either be stationary (a), or rotating (b). The horizontal tiers can be built to be isolated (c) for better environmental control for each row. Vertical systems can also use balconies (d) or a cylindrical design (f) with crops growing around a vertical cylinder. Finally, vertical farms can incorporate a vertical wall design (e) where plants are grown outwards from a wall. This design was pioneered by Dr. Nate Storey from Plenty (formerly at Bright Agrotech) and is also the method of choice for us.
There are a range of benefits that vertical farming has over single plane production that are well established. However, the benefits of a vertical wall design are less well known when compared to other vertical farming design.
Different applications for hydroponic farming
Hydroponics is a flexible method for soilless farming, and the technologies involved can be utilized in a variety of ways. Hydroponic farming techniques like the Nutrient Film Technique (NFT) and Deep Water Culture (DWC) are commonly used either as the primary or supplementary technologies alongside more conventional greenhouse methods. In addition, it hydroponic farming is an excellent solution for urban environment like large cities. In fact, recent developments in hydroponic farming has seen an increase in vertical farms being established in large population centres, bringing food production right next to the consumers. This is also echoed in our mission statement which is to make indoor farming mainstream.
In addition to greenhouses and urban centres, hydroponic farming can also be used in developing countries where resource scarcity is a prevalent problem. Hydroponics is not only an efficient method to grow plants in food deserts, or in otherwise infertile lands, but it has also shown to have potential as a solution for crisis environments where local production has been ravaged by natural disasters or by war. The minimal use of water and the ability to grow plants in a controlled environment makes hydroponics ideal to any location where conventional farming would not work, either because of circumstantial or persistent reasons.
Finally, soilless farming is also considered as one of the go-to solution for space applications. In fact, NASA is currently researching and testing soilless farming technologies at the International Space Station with the vision that these technologies will provide food for their astronauts in future Moon and Mars missions.
Contact us
As you can see, hydroponic technologies have a limitless amount of applications and it can solve a range of environmental and social issues around the globe. If you are interested in hearing more about these technologies and how we approach hydroponics, please contact us using the contact form.
Sources:
Beacham, A. M., Vickers L. H., & Monaghan, J. M. (2019) Vertical farming: a summary of approaches to growing skywards. The Journal of Horticultural Science and Biotechnology, 94(3), pp. 277-283.
Khan, S., Purohit, A., & Vadsaria, N. (2020). Hydroponics: current and future state of the art in farming. Journal of Plant Nutrition, 44(10), 1515–1538.
NoSoilSolutions. https://www.nosoilsolutions.com/6-different-types-hydroponic-systems/