History of Hydroponics

What is Hydroponics?

In Latin, the word hydroponics means literally "water working." Hydroponics is the practice of growing plants in either a bath or flow of highly oxygenated, nutrient enriched water.

In soil, biological decomposition breaks down organic matter into the basic nutrient salts that plants feed on. Water dissolves these salts and allows uptake by the roots. For a plant to receive a well balanced diet, everything in the soil must be in perfect balance. Rarely, if ever, can you find such ideal conditions in soil due to contamination and biological imbalances.

With hydroponics, water is enriched with these very same nutrient salts, creating a hydroponic nutrient solution that is perfectly balanced. And since this hydroponic nutrient solution is contained, it does not harm our environment as does runoff from fertilized soil. Additionally, very little water is lost to evaporation in a hydroponic system, owing to its application in drought stricken areas.

To support the plants in a hydroponic system, an inert soil-free medium like fiber, sand or stone, may be used to anchor the roots. These hydroponic mediums are designed to be very porous for excellent retention of air and water that's necessary for a healthy plant - roots need to breathe too!

In addition to a perfectly balanced diet, hydroponic plants have their food and water delivered directly to their roots. This way, the energy normally used to develop long roots can be redirected to growing more plant, which is a great benefit indeed! With the proper exposure to natural sunlight or supplemental grow lights, your hydroponic plants will grow many times faster, bigger and healthier than those grown in soil.

What is Aeroponics?

Aeroponics is an application of hydroponics without a growing medium, although a small amount may be used to germinate the seed or root a cutting. Plant roots are suspended mid-air inside a chamber kept at a 100% humidity level and fed with a fine spray of nutrient solution. This mid-air feeding allows the roots to absorb much needed oxygen, thereby increasing metabolism and rate of growth reportedly up to 10 times of that in soil. And there is nearly no water loss due to evaporation.

Hydroponics was practiced many centuries ago in Amazon, Babylon, Egypt, china and India where ancient men used dissolved manure to grow cucumber, watermelons and other vegetables in sandy riverbeds. The “hanging harden of Babylon” and the Aztec’s floating farms were actually prototypes of hydroponic systems. Later, when plant physiologists started to grow plants with specific nutrients for experimental purposes, they gave the name “nutriculture.”

The word Hydroponics is derived from the Greek word Hudor for water, and Ponos meaning labor, thus meaning working with water. Hydroponics has been in use for nearly 300 years by a man named John Woodward. It wasn't until the 1930's that Dr. William R. Gericke, an American professor, set up outdoor growing units, producing tomato plants with a height of 25 feet tall. In 1944 the United States government actually began using hydroponics as a way to feed the U.S. troops in the pacific. 0.6 acres provided vegetables enough to feed 400 men a day.

Interest in practical application of “nutriculture” developed in 1925 when the green house industry expressed interest in its use. Green house soils had to be replaced frequently to overcome problems of soil structure, fertility and pests. As a result, researchers became interested in the potential use of nutriculture to replace conventional soil culture.

In 1929, Dr William F. Gericke of the University of California succeeded in growing tomato vines of 7.5 m height in nutrient solutions. He named this new production system “hydroponics” a word derived from Greek to reflect the importance of ‘Hydros’ (water) and ‘Ponos’ (working). Thus, hydroponics broke the laboratory bounds and entered the world of practical horticulture. The term hydroponics originally meant nutrient solution culture. However, crop growing in inert solid media using nutrient solution is also included in hydroponics in broad sense.

During 1960s and 70s, commercial hydroponics farms were developed in Abu Dhabi, Arizona, Belgium, California, Denmark, German, Holland, Iran, Italy, Japan, Russian Federation and other countries. During 1980s, many automated and computerized hydroponics farms were established around the world. Home hydroponics kits became popular during 1990s.

In Sri Lanka, the hydroponics system of cultivation is in its infancy. Many use inert solid medium such as coconut fibre or coir-dust with fertigation and some use balanced nutrient solution alone employing both circulating and non-circulating methods in small and medium scales.

Soils naturally maintain the temperature and aeration needed for root growth. When the soil is poor, plant growth and yield decline also due to unsuitable aeration and temperature. Plant cultivation is impossible under ill drained condition due to these conditions. Soil adjusts itself to provide suitable conditions for plant growth. It is called the buffer action of the soils. Plants also absorb nutrients released through natural mineralization.

In a solution or inert medium, maintenance of acidity or alkalinity (pH) and electrical conductivity (EC) in suitable ranges for plant root system is called buffer action. This requirement must be artificially maintained in hydroponics. In any hydroponics system the following basic requirements must be maintained at optimum levels.
• Buffer action of water or the inert medium used.
• The nutrient solution or the fertilizer mixture used must contain all micro and macro elements necessary for plant growth and development.
• Buffer action of the nutrient solution must be in the suitable range so that plant root system or the inert medium is not affected.
• The temperature and aeration of the inert medium or the nutrient solution is suitable for plant root system.

Classification of Hydroponics/ Soil-less Culture

The term hydroponics originally meant nutrient solution culture with no supporting medium. However, plant growing in solid media for anchorage using nutrient solution is also included in hydroponics. This technique is called aggregate system. Hydroponics systems are further categorized as open (i.e., once the nutrient solution is delivered to the plant roots, it is not reused) or closed (i.e., surplus solution is recovered, replenished and recycled). Current hydroponics systems of cultivation can be classified according to the techniques employed. A hydroponic technique refers to the method of applying nutrient solution to the plant roots.
Large numbers of hydroponic techniques are available. However, consider following factors in selecting a technique.
• Space and other resources available
• Expected productivity
• Availability of suitable growing medium
• Expected quality of the produce – colour, appearance, free from pesticides, etc.
1. Solution culture or Liquid hydroponics -Circulating methods (closed system)
Nutrient film technique (NFT)
Deep flow technique (DFT)
Non-circulating method (open systems) Root dipping technique Floating technique Capillary action technique
2. Solid media culture (Aggregate systems)
These can be open systems or closed systems.
Hanging bag technique
Grow bag technique
Trench or trough technique
Pot technique
3. Aeroponics -Root mist technique
Fog feed technique

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