Hydroponics

Hydroponics is the science of growing plants without soil. If you haven't heard of hydroponics, you may have heard of "soil-less culture" which is another name often used to describe the same thing. The same natural elements necessary for plant growth in soils are used, with the advantage that your plants are not restricted by weeds or soil-borne pests and diseases.

Hydroponic techniques, though they may seem to be a new technology, have been in use for centuries. The earliest known use of hydroponics are the Hanging gardens of Babylon, the Floating Gardens of Kashmir and the Aztec people of of Mexico who used rafts on shallow lakes to grow plants. Also, hieroglyphic records in Egypt dating back to several hundred years B.C. describe the growing of plants in water. More recently, mobile hydroponic farms have been used to feed soldiers during the Second World War in the South Pacific.

Today, hydroponics is beginning to play a more important role in the world's agricultural production. Increasing populations, climatic changes, lack of water in some areas or poor quality water are all factors influencing the trend towards alternative methods of horticulture. Hydroponics is allowing many to have fresh food where normally they would have to have it shipped in or stored for long periods. A prime example of this is on Naval submarines, where hydroponics is used to supply the crew with fresh fruit and vegetables. Of more benefit is the use of hydroponics in developing countries, where it provides intensive food production in limited areas. The only restraints to a viable hydroponic system is the availability of water and nutrients. In areas where fresh water is not available, desalinated seawater can be used.

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 formula of nutrient solution varies according to the variety of the crop, the stage of crop growth, and the parts of the crop to be harvested as well as environmental factors including temperature, day-length and humidity. For example, a chemical called potassium hydrogenphosphate contained the element P and K weighting in 263.00 grams, potassium nitrate containing N and K weighting 583.00 in grams, etc.

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 b 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 separate tank. In both methods, the solution 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. On the contrary, the excess solution in a closed system is collected and reused, forming a closed loop of solution flow.

There are many benefits of hydroponics. Hydroponics methods are usually practiced in association with greenhouses. The method, although expensive, is implemented worldwide for commercial purposes because of many reasons.

A hydroponically grown fruit or vegetable is grown without the use of soil from the time the seed is sown.

Each plant is grown in sythetic substance resembling cotton balls. It is made by subjecting molten rocks to a strong blast, and is sometimes referred to as mineral cotton. The material acts as a trellis for the roots to inner twine in. The nutrients and minerals that the plant requires are delivered through the watering system that is computer controlled.

By reducing the growing environment to clean synthetics the grower eliminates soil borne diseases and weeds, which eliminates the need for possibly harmful herbicides. The closed environment also eliminates soil borne insects and pests, and if unwanted insects present themselves, they can be eliminated through the use of predator insects. In simple terms, beneficial insects destroy unwanted insects.

Whether you appreciate the fact hydroponic vegetables are harvested vine ripened, available year round, or grown in a sterile environment without the use of herbicides and pesticides, the fact it is hydroponic vegetables are a superior product.

6s Sam Leung