What is Hydroponics?

By Benedette Cuffari, M.Sc.May 9 2016

Image Credit: Murph/Shutterstock.com

Derived from the two Greek words hydro and ponos, meaning water and labor respectively, hydroponics is defined as a method of growing plants in water, rather than in soil¹. While this process may seem arbitrary, the growing of plants in nutrient-rich water has been practiced for centuries.

The History of Hydroponics

Hydroponic systems have dated back to its applications in the ancient Hanging Gardens of Babylon, as well as the floating gardens of the Aztecs in Mexico. In fact, the earliest use of hydroponics in the United States can be traced to the 1930s in which California scientist, William Frederick Gericke, popularized the soilless culture of plants².

Further application of this technology took place during the Second World War, where large hydroponic gardens in several western Pacific islands were developed by the United States Army in order to supply fresh vegetables to local troops.

The Hydroponic System

Within a hydroponic system, roots of a plant are suspended in either a static, continuously aerated nutrient solution, or within a continuous flow or mist of nutrient solution. This pH adjusted nutrient solution is comprised of 16 of the 19 required elements for survival, some of which include carbon, oxygen, hydrogen, potassium, iron, and copper².

The pH, which measures the acidity or basicity of a given solution, within the hydroponics system is of critical importance to the viability of any plant’s growth. While this pH level will vary for each plant, most plants grow best in a slightly acidic environment, with a pH range between 5.5 - 6.0³.

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Photosynthesis Within a Hydroponic System

A crucial aspect of plant growth is the process of photosynthesis, in which plants, as well as other organisms such as algae and certain bacteria, convert light energy into the chemical energy required for growth. Within a hydroponics system, this light energy is typically provided by an artificial lighting source, such as a lamp, combined with a shade or reflector used to direct light towards the plant.

During photosynthesis, carbon dioxide (CO₂), a colorless and odorless gas, is absorbed by the plants and reduced to produce carbon and oxygen⁴. While small amounts of oxygen are used by the plant, most of this oxygen reserve is released back into the atmosphere.

Certain ways in which CO₂ is added to a hydroponics system is through bottled CO₂ or a CO₂ generator⁵. It is imperative to maintain precise control over the CO₂ levels within a hydroponics system through the use of a CO₂ monitor in order to ensure optimal conditions for plant survival.

Benefits over Soil for Plant Growth

Simplistic in its model, the hydroponics system offers several advantages over the traditional use of soil for plant growth. The plant is not grown in soil, which provides the ability to control exactly what type of nutrients are entering the plants, allowing workers to immediately correct any possible nutritional deficiencies⁶.

This control over the environmental growth conditions further guarantees the eradication of pests, fungi, and soil-borne plant diseases that are typically found in open systems. The conservative nature of the hydroponics system is further emphasized by its prevention of leaching, a process in which a considerable amount of plant nutrients are lost to the soil following rain or irrigation².

While taking into consideration the cost of construction and the required training to maintain these systems, hydroponics remains one of the most advantageous options for agriculture production to date. The utilization of hydroponics allows for crops to be grown in a protective and sterile environment while producing maximum yields in a timely manner.

While this agricultural approach appears promising, there is a lack of research on hydroponics within the scientific community. This versatile technology has found its applications in industry, agriculture, and government, and may offer future, more capital-intensive solutions to various manufacturing problems.

References and Further Reading

1. Merriam-Webster
2. Jones, J. Benton. Hydroponics: A Practical Guide for the Soilless Grower. Boca Raton, FL: St. Lucie, 1997. Print.
3. pH
4. What Is Photosynthesis?
5. Using CO2 Successfully
6. The Five Advantages of Hydroponics

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