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Hydroponics

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Hydroponics is a specialized form of horticulture used to grow plants without soil. It is a subset of hydroculture, which focuses on growing plants in water. Instead of using earth, growers use water-based mineral nutrient solutions in artificial environments. These solutions provide the essential food that plants need to thrive.

Hydroponic onions, NASA -- 17 June 2004
Hydroponic onions, NASA -- 17 June 2004

This method is vital for modern agriculture because it can significantly decrease water usage. It also allows for higher biomass and protein production compared to other substrates. This means more food can be grown in the same amount of space and time.

In a hydroponic system, the plant roots interact with nutrients in specific ways. Some plants grow with their roots directly exposed to a nutritious liquid. Other plants are mechanically supported by an inert medium. An inert medium is a material that does not provide nutrients itself. Common examples include perlite, gravel, or expanded clay aggregate.

Hydroton
Hydroton

Even when using these supports, the roots can change the chemistry of their surroundings. They can affect the pH of the rhizosphere, which is the area around the roots. They also release root exudates, which are substances that affect the biological balance of the nutrient solution.

There are several distinct ways to irrigate these systems. One category is sub-irrigation, where the nutrient solution is supplied from below. In these systems, roots absorb moisture by pulling it upward. Examples include deep water culture and ebb-and-flow systems.

Systeme FLOOD&DRAIN 573px
Systeme FLOOD&DRAIN 573px

An ebb-and-flow system involves flooding the roots with solution and then allowing it to drain away. Another method is top-irrigation, where the solution is applied from above. A famous version is the nutrient film technique (NFT).

Leafy Greens Hydroponics
Leafy Greens Hydroponics

In NFT, a thin film of nutrient solution flows continuously over the roots.

The history of soilless cultivation began with early scientific observations. In 1627, Francis Bacon published the first work on growing terrestrial plants without soil. Later, in 1699, John Woodward discovered that plants grew better in less-pure water than in distilled water. Between 1859 and 1875, German botanists Julius von Sachs and Wilhelm Knop developed the technique further. They proved that land plants could absorb nutrients from watery solutions to grow vigorously.

Water-cultivate a crocus
Water-cultivate a crocus

This research helped establish soilless cultivation as a standard teaching technique in the 19th and 20th centuries.

William Frederick Gericke played a massive role in bringing these ideas to the public. In 1929, he began promoting solution culture for agricultural crop production at UC Berkeley. He famously grew large tomato vines in his backyard using mineral nutrient solutions. In 1937, the term "hydroponics" was introduced to him by the phycologist W. A. Setchell. The name is a neologism derived from the Greek words "hydor," meaning water, and "poneo," meaning to cultivate.

Hungarian wax peppers roots being revealed IMG 5673
Hungarian wax peppers roots being revealed IMG 5673

Although Gericke faced academic skepticism, his work became the basis for modern hydroponic growing.

Hydroponics has been used in many practical and extreme environments. In the 1930s, it was used on Wake Island to grow vegetables for airline passengers because there was no soil. From 1943 to 1946, Major Daniel I. Arnon used these methods to feed troops on the barren Ponape Island. Today, the industry is growing rapidly. The global hydroponics market was forecast to grow from US$226.45 million in 2016 to US$724.87 million by 2023. Large-scale commercial greenhouses in Canada already produce massive amounts of tomatoes, peppers, and cucumbers.

Looking toward the future, hydroponics is essential for space exploration. NASA researchers study these systems for their Controlled Ecological Life Support System (CELSS). They want to create bioregenerative life support systems for long-term space travel.

CDC South Aquaponics Raft Tank 1 2010-07-17
CDC South Aquaponics Raft Tank 1 2010-07-17

These systems would use plants to produce oxygen and food while removing carbon dioxide. Scientists are even studying how plants grow in different gravity environments. This includes the low gravity of Earth orbit, the 1/6 g of the Moon, and the 1/3 g of Mars. Hydroponics may eventually allow humans to live on other worlds.

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🖼️ Images & Media (21)
File:Hydroponic onions, NASA -- 17 June 2004.jpg
Hydroponic onions, NASA -- 17 June 2004.jpg
File:Hydro system.jpg
Hydro system.jpg
File:Hydroponic farming, USA (9386).jpg
Hydroponic farming, USA (9386).jpg
File:CDC South Aquaponics Raft Tank 1 2010-07-17.jpg
CDC South Aquaponics Raft Tank 1 2010-07-17.jpg
File:Leafy Greens Hydroponics.jpg
Leafy Greens Hydroponics.jpg
File:Systeme AEROPONIC.svg
Systeme AEROPONIC.svg
File:Water-cultivate a crocus.jpg
Water-cultivate a crocus.jpg
File:Systeme FLOOD&DRAIN 573px.jpg
Systeme FLOOD&DRAIN 573px.jpg
File:Bengal System.png
Bengal System.png
File:Hungarian wax peppers roots being revealed IMG 5673.JPG
Hungarian wax peppers roots being...
File:Expo 2015 - Coltura idroponica al padiglione del Belgio.jpg
Expo 2015 - Coltura idroponica al...
File:Rockwool 4lbs per ft3 fibrex5.jpg
Rockwool 4lbs per ft3 fibrex5.jpg

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