Hydroponics is a subset of hydroculture, which is a method of growing plants without soil, by using mineral nutrient solutions in a water [login to view URL] plants may be grown with only their roots exposed to the nutritious liquid, or the roots may be physically supported by an inert medium such as perlite, gravel, or other [login to view URL] inert media, roots can cause changes of the rhizosphere pH and root exudates can impact the rhizosphere biology.
The nutrients used in hydroponic systems can come from many of different sources, including (but not limited to) fish excrement, duck manure, purchased chemical fertilisers, or artificial nutrient solutions.
Plants commonly grown hydroponically, on inert media, include tomatoes, peppers, cucumbers, lettuces, marijuana, and model plants like Arabidopsis thaliana.
Techniques of Hydroponics:-
1. Static solution culture:-In static solution culture, plants are grown in containers of nutrient solution, such as glass Mason jars (typically, in-home applications), pots, buckets, tubs, or tanks.
2.Continuous-flow solution culture or NFT system:- In continuous-flow solution culture, the nutrient solution constantly flows past the roots. It is much easier to automate than the static solution culture because sampling and adjustments to the temperature, pH, and nutrient concentrations can be made in a large storage tank that has potential to serve thousands of plants. A popular variation is the nutrient film technique or NFT, whereby a very shallow stream of water containing all the dissolved nutrients required for plant growth is recirculated past the bare roots of plants in a watertight thick root mat, which develops in the bottom of the channel and has an upper surface that, although moist, is in the air. Subsequent to this, an abundant supply of oxygen is provided to the roots of the plants. A properly designed NFT system is based on using the right channel slope, the right flow rate, and the right channel length. The main advantage of the NFT system over other forms of hydroponics is that the plant roots are exposed to adequate supplies of water, oxygen, and nutrients. In all other forms of production, there is a conflict between the supply of these requirements, since excessive or deficient amounts of one results in an imbalance of one or both of the others. NFT, because of its design, provides a system where all three requirements for healthy plant growth can be met at the same time, provided that the simple concept of NFT is always remembered and practised. The result of these advantages is that higher yields of high-quality produce are obtained over an extended period of cropping. A downside of NFT is that it has very little buffering against interruptions in the flow (e.g., power outages). But, overall, it is probably one of the more productive techniques.