Hydroponics: Concepts and Methods
Hydroponics is one of the many methods of soilless agriculture through which plants are grown using mineral nutrient solutions in water, without soil. Many commodity crops like tomatoes, onions, lettuce and cabbage have been successfully cultivated through hydroponics, and their produce well-accepted in many markets. The theory behind the method is that the soil is only a mineral nutrient reservoir and hence, it is not very essential to plant growth. The mineral nutrient can be introduced into a plant’s water supply artificially which is then readily absorbed by the plant’s root. The concept of hydroponics is significant in today’s world as it contributes to the growing concern for steadier food supply, as well as the reduction of suitable arable land for agriculture.
There are many hydroponics techniques which are based on how the mineral nutrients are made available for plant use. Here are the five techniques of hydroponics:
Static Solution Culture. In this technique, plants are grown in containers of nutrient solution, such as plastic buckets, tub, or tanks. Condition for culture is monitored such as the solution of the nutrient been applied to the plants. The solution is usually aerated using common aquarium pump. If un-aerated, the solution level must be kept low enough so that the roots may also get sufficient oxygen. When the nutrient solution has been depleted to a low level, fresh water may be added. An example of culture that uses such procedure is on garden hydroponics, this may be due to its space minimum requirement.
Continuous-flow solution Culture. The setup for this technique is very much similar to the previous method except that the nutrient solution is automated to constantly past the roots of the plants. This is also done on large container, where solution may be kept concentrated and potentially serves thousands of plants.
Aeroponics. In this technique, plants are grown in air or mist environment without the use of soil or an aggregate medium. The basic principle of aeroponic growing is to grow plants suspended in a closed or semi-closed environment by spraying the plant's dangling roots and lower stem with an atomized or sprayed, nutrient-rich water solution. Ideally, the environment is kept free from pests and disease so that the plants may grow healthier and more quickly than plants grown in a medium. However, since most aeroponic environments are not perfectly closed off to the outside, pests and disease may still cause a threat. Controlled environments advance plant development, health, growth, flowering and fruiting for any given plant species and cultivars.
Passive Hydroponics. This is a method of growing plants without soil; instead, an inert porous medium transport water and fertilizer to the roots by capillary action. Some kind of a “wick” system is used. Water and fertilizer are held in a reservoir and conducted to the roots as necessary, reducing labor and providing a constant supply of water to the roots. In the simplest method, the pot sits in a shallow solution of fertilizer and water or on a capillary mat saturated with nutrient solution.
Ebb and Flow. In this technique, pots are filled with an inert medium which does not function like soil or contribute nutrition to the plants but which anchors the roots and functions as a temporary reserve of water and solvent mineral nutrients. The hydroponic solution alternately floods the system and is allowed to ebb away.
There are still many other systems of hydroponics which are variations of the five aforementioned. They include deep water culture, bubbleponics, and run-to-waste.