Hydroponics ~ Karen Chan 6S 22

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 hydroponic culture as compared with traditional planting methods. In some cases, the plants are supported by inert media such as gravel, perlite, rockwool and vermiculite.

A primary nutrient solution usually contains potassium nitrate, calcium nitrate,potassium hydrogenphosphate and magnesium sulphate in distilled water. A small amount of fungicide is usually added to prevent the growth of moulds in the solution. The different types of nutrients contents of the solution varies according to the variety of the crop, the stage of crop growth, the parts of the crop to be harvested as well as environmental factors including temperature, day-length and humidity.

There are different types of hydroponic 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 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. In both methods, the solution must be aerated for aerobic respiration of the root cells.

In an open hydroponic system, the nutrient solution is distributed from a reservoir to the plants, and the excess solution is drained away as waste. On the contrary, the excess solution in a closed system is collected and reused, forming a closed loop of solution flow.

This method has quite a lot of benefits. Hydroponic methods are usually practiced in association with greenhouse. The crops are grown under entirely controlled environment in greenhouses. The yield of crops increase, and quality of crops is improved because the factors contributing to their growth can be controlled within optimal levels. In addition, the effects of climatic changes are minimized in sheltered environment. Also, the problems of pests and diseases can be kept under control. At the same time, the unit cost of crops may be reduced as a result if high planting densities, shortened growing seasons and the use of continuous, automated production methods. Moreover, farming can be conducted in areas where the soil or the climate is not suitable for growing crops. The use of water and nutrients become more efficient in closed hydroponic systems too. Leaching of nutrients is prevented and wastage as well as pollution problems are minimized. With specific treatments, hydroponically grown crops can be made more attractive and tastier.

The main disadvantages of hydroponics are the cost of set up, together with a higher level of technical expertise needed to maintain and run the hydroponics system. However, this technical expertise can range from very basic through to extremely advanced, it’s all up to the individual grower and their needs.

Hydroponic technology can efficiently generate food crops from barren desert sand and desalinated ocean water, in mountainous regions too steep to farm, on city rooftops and concrete schoolyards and in arctic communities. In highly populated tourist areas where skyrocketing land prices have driven out traditional agriculture, hydroponics can provide locally grown high-value specialty crops such as fresh salad greens, herbs and cut flowers.