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Now, Hydroponics has many applications. It is used worldwide to grow plants on land or in water without dirt or soils, for both commercial and home use. The roots of the plant do not contact the growing medium or soil, but instead reside in a solution containing all of the nutrients that are required for plant growth.
The environmental conditions within which hydroponic plants are grown can be controlled to create optimal growing environments. Hydroponics is used to grow greenhouse crops on a year-round basis and to produce healthy food economically.
The method was developed in the United States during World War II by W. F. Gericke, an agricultural scientist from the University of California, who designed and built a floating system for cultivating tomatoes under water. The first working model consisted of a wooden frame with hooks into which clay pots were placed; Gericke called his invention "earth-less culture".
The word hydroponics is derived from the Greek words "hydro" meaning water and "ponos" meaning labor.
Modern commercial operations use biofarming technology advanced by NASA in the production of plants that support life in outer space. Without soil, astronauts would be unable to grow vegetables and fruits.
(image from NASA's biofarming division)
There are two different styles of hydroponic systems:
A passive system uses the environment as a growing medium, usually employing some sort of wicking mechanism to draw water and nutrients into the plant's root zone. Passive systems are generally less expensive than active systems, but they cannot be regulated as precisely.
An active system is used to control the environment in which the plants are grown, providing precise levels of water and nutrients. Active systems cost more to build, but they provide improved plant growth and greater yields.
Active hydroponic systems fall into two categories:
Ebb-and-flow systems flood crops with nutrient-rich water and then drain the solution back into a reservoir. This allows for large quantities of growing media to be used while still providing good aeration for the roots. About half of commercial hydroponic growers use ebb-and-flow systems, which are often called NFT or flood/drain systems.
Nutrient film technique systems use shallow water tables and grow mediums that have low resistance to flow. Nutrients are pumped through the table under pressure, providing good aeration for roots. The nutrient solution is re-circulated constantly, ensuring an even concentration of nutrients in the water.
In Hydroponics, plants need less space compared to soil grown plants because of the absence of a macroporous substrate, which is replaced by inert material (rock wool, perlite) or a nutritive solution. In this way, hydroponics grows plants on up to 30% less land compared with conventional farming.
The nutrients in hydroponic systems are dissolved in water; most commercial hydroponic systems recirculate a constant supply of nutrient solution. Nutrient levels are carefully maintained, typically within a few percentage points of the optimum amount needed by plant roots for healthy growth. The controlled environment in hydroponics allows for greater control over pH and water temperature than traditional agriculture.
Growing plants hydroponically is usually more expensive than growing them in soil due to the cost of the required equipment (lights, climate control systems, etc.) and because setup costs are higher. However, hydroponic systems are gaining popularity with small-scale home and market gardeners because of their ability to be operated on a smaller budget.
However, once the initial costs of equipment are paid off, hydroponics becomes cheaper than conventional farming if one takes into account soil replacement expenses, the skill required in soil management, as well as the lack of labor required in a hydroponic setting.
The concept that plants mainly need oxygen and water to survive has been known for millennia. Theophrastus (ca. 372–287 BC) mentioned it in his book "Enquiry into Plants". Edward Blyth was the first to mention commercial hydroponic gardening, with a 16-page article titled "Watersprout Culture" in an 1870 issue of the "Journal of the Indian Agricultural Society".
In 1886, Bodington and Phillips patented "the artificial culture of plants without soil", which connected a system of pipes to hydroponically grown fruit trees. The first commercial implementation was by Julius Hensel in Germany, who started selling systems for greenhouse use in the 1920s. In 1930, Liberty Hyde Bailey and Emerson published "The Effect of Hotbeds, Coldframes, and Shelters on the Growth of Tomato Plants".
In 1937, The U.S department of agriculture released two circulars: Circular 318 – Dates for Planting Tomatoes in Florida, and Circular 404 – Suggestions for Increasing Marketable Yields of Tomatoes. These publications describe hydroponic techniques that are still in use today, but utilized larger pots and commercial fertilizers.
In the 1940s, Dr. William F. Tracy extended his research on plant nutrition, which was originally confined to growth of plants in sandy soil, to include nutrient solutions in a paper titled "The culture of Chrysanthemums in synthetic media".
In the 1950s to 1960s, research on hydroponics suffered a lull. The space race and push to land men on the moon caused the U.S government to fund research into other things, such as semiconductors, instead of hydroponic food production systems.
Hydroponics was rediscovered by film maker and inventor Flux Davenport. He was also the founder of "The International Society of Organic Agriculture Movements" (ISOM) in 1991, and he organized the first conference on organic urban agriculture at his home in Oakland, California.
In 1977, a breakthrough occurred when B.C. ("Bud") Wolfe published the book "The Potting Mix".
It came at a time when interest was rekindled in hydroponics, and contained all the information needed to recreate a simple nutrient film technique (NFT) system. However, it did not make much of an impact until 1986 when Wolfe's article on "How I Feed My Plants: A Layman's Guide to NFT" was published in Alternative Agriculture, a trade journal.
The first commercial aquaculture system was developed by Dennis Hoagland while working at the Department of Fisheries & Wildlife at the University of Wisconsin-Madison, and is called known as Hoagland hydroponics or the Wisconsin System. The "Wisconsin System" consists of a recirculating, re-oxygenating system that simultaneously feeds plants and algae. It was designed to be low cost, self-contained with on-site nutrient recovery, and modular. The design has been extensively verified in the laboratory by Dr. Robert A. Berglund at the University of Wisconsin–Madison Department of Biosystems Management. This is the same technology that was used for a NASA funded project designed by Dr. Berglund to grow vegetables in space both on Earth and in a micro-gravity environment (using NASA's reduced gravity aircraft). The University of Wisconsin system has been licensed to over 50 companies worldwide, and commercialized as the Rapid Rooter and Rapid Beds hydroponic growing systems.
The current interest in hydroponics was spurred by the development of the first prototypes for passive sub-irrigation (PSI) systems, developed following research on plant nutrition at The University of California, Davis. Subsequently a significant number of people have experimented with different mediums, nutrients, and growing configurations. A trade magazine, Hydro Culture, was started in 1983, but ceased publication five years later.
Another advance took place in the early 1990s with the development of a PSI based hydroponic system called raft culture or floating grow beds by Dutch scientist Jeroen van den Bosch of the University of Wageningen. The bed comprises plastic or bamboo rafts placed on the surface of a body of water. Plants are grown in culture medium suspended between the rafts, and roots extend into the water below, where oxygen is dissolved. This passive hydroponic system has become very popular with hobbyists because it can be constructed using inexpensive materials found at local building supply outlets.
Hydroponic production has since been adopted by some, but not all professional growers. It is one of several new techniques used by hydroponic farmers in controlled environments such as greenhouses and high tunnels. Hydroponics is an efficient system for growing crops because it allows the grower to control what nutrients are supplied to the plant and how much light and water it receives. The nutrient solution can be reused for a period of time (typically weeks), which reduces the environmental impact compared to traditional soil-based farming.
It continues to be a force in the agricultural community and worth investment. Check out some resources to get started.