Hydroponics

Hydroponics is a method of cultivating plants in nutrient solution, with or without the use of an artificial medium for mechanical support. No soil is used in hydroponics culture as compared with traditional planting methods. Sometimes, an inert media such as gravel, perlite, rockwool and vermiculite is needed for the support of the plants. Nutrient solutions are also needed in hydroponics for the well being of plants. A primary nutrient solution usually contains potassium nitrate, calcium nitrate, potassium hydrogenphosphate and magnesium sulphate in distilled water. A small amount of fungicide is also added to prevent the growth of moulds in the solution. The formula of nutrient solution varies according to the variety of the crops, the stages of crop growth, and the parts of the crop to be harvested as well as environmental factors including temperature, day-length and humidity.

Nowadays, there are a variety of hydroponics systems currently in use in different parts of the world. They can be categorized by the medium that the roots submerge in, or by the way nutrient solution flows in the system. The most commonly used hydroponics systems are the Liquid culture and aggregate culture and Open system and closed system.

The liquid culture method is the simplest to set up on a small scale. The roots are hanging into the solution directly. Without an inert medium, the plant body is usually held on a piece of Styrofoam placed over the nutrient solution. This method is suitable for short plants such as lettuce and spinach. For taller plants such as tomatoes and cucumbers, they may be hung loosely with strings for support. In aggregate culture, the plant roots grow into an inert medium and are irrigated with complete nutrient solution held in a separate tank. The solutions of both methods must be aerated for aerobic respiration of the root cells. In an open hydroponics system, the nutrient solution is distributed from a reservoir to the plant, and the excess solution is drained away as waste. And in a closed system, the excess solution is collected and reused again, which forms a closed loop of solution flow.

Hydroponics is usually practiced in association with greenhouses. The method, although expensive, is used worldwide for commercial purposes because of the advantages that it brings about.

Firstly, crops are grown under an entirely controlled environment in greenhouses. The yield of crops increase, and the quality of crops is improved because the factors contributing to their growth can be controlled within optimal levels. Secondly, the effects of climatic changes can be minimized in sheltered environment. Growing seasons therefore can be extended. The problems of pests and diseases can be kept to minimum. And the cost of crops may be reduced because of the high planting densities, shortened growing seasons and the use of continuous, automated production methods. Also, the use of water and nutrients become more efficient in closed hydroponics systems. So that leaching of nutrients, wastage and pollution problems can be prevented. Lastly, farming can be conducted in areas where soil or climate is not suitable for growing crops. Through specific treatments, crops grown by hydroponics method will be more attractive and tastier.