In simple terms hydroponics is a way to feed plants with the nutrients and water they need. This is usually done by circulating a nutrient solution past the plants roots, catching the unused nutrient and recirculating it. Water conservation In a soil, excess water can drain and evaporate away before the plants can use it. In a recirculating hydroponic system, water is conserved in the system.

There are no losses to drainage and as long as evaporation is controlled hydroponics uses as little as one tenth of the water that a conventionally grown crop would require. It is easy to see that hydroponics can be very useful in areas where water resources are limited. In the Middle East (particularly Israel and the Gulf States), Africa, Australia and some of the desert areas in the USA hydroponics represents the only practical way of growing many crops. Even in space where there is no soil and water is very expensive.

Nutrient conservation

In a soil, nutrients which have not yet been used by the plant can be washed away by rain or irrigation water. This leachate ends up in the ground water and contaminates rivers and lakes leading to algal blooms, deoxygenation and ultimately is fatal to fish and other animals. Also salts can build up in ground water reserves making them too saline to use for drinking or irrigation (a particularly major problem in Australia at the moment). Organic methods of soil management help to minimise leaching. In a recirculating hydroponic system, there is no loss of nutrients to the environment - all the nutrients put into the system are used up by the plants. This results in a very efficient pollution free method of growing which requires less nutrient than a conventional system

Is it Organic?

In the UK organic status is regulated by the Soil Association (which immediately throws up problems for a soil-free method of growing!). Many aspects of the Organic Standard do not apply to hydroponics eg maintaining soil fertility and structure; controlling weeds in an approved manner. Hydroponic growers do not maintain the soil - they leave it alone! They do not control weeds because there are none! At The Hydroponicum we choose not to use chemical pesticides. This means that the food crops are free from residues of these noxious substances. The other major issue is the origin of the nutrients. The first point to remember is that more than 98% of any plant is made up of carbon, hydrogen and oxygen - elements it derives entirely from air and water. The word "organic" just means anything containing carbon. The organic part of the plant is produced from the air (carbon dioxide). A hydroponic nutrient solution aims to mimic what the plants would take out of the soil. Whatever method you use to grow a plant (organic, hydroponic or "conventional") all plants take up inorganic chemicals through their roots. In soil these chemicals come from the processes going on in the soil. The breakdown of organic matter and the dissolving of salts from the mineral particles in the soil release nitrates, phosphates and a range of other nutrients. Some of the trace elements are required in minute quantities. If you were to take away everything from the soil except what the plants needed then you would have in front of you a small pile of inorganic chemicals. Although the nutrients in a hydroponic system are usually produced synthetically they are chemically identical to those the plants would find in a soil. In general the main problem with using artificial nutrients on a soil is not what the plants use but what they don't use. As much as 80% of the more soluble nutrients can be leached out of the soil by rainfall or irrigation before the plants have a chance to use them causing the problems mentioned earlier

Sustainability

Hydroponics can provide a sustainable solution to growers with difficult soil and climate conditions (not everyone has deep fertile soil and a benign climate in which to grow organic crops). Limiting consumption to strictly organically grown crops would result in having to import more food. As it is 70% of organically grown food sold in the UK is imported from other countries. If you look at the organic produce in your local supermarket you are likely to see spring onions from Mexico, beans from Zimbabwe, salad leaves from California, raspberries from Chile.the list goes on. Large amounts of air fuel and diesel has been consumed to get these products from the grower, across the world to the end user yet they are still described as organic. The environmental cost of the transport outweighs the benefits of growing them organically in many cases. "Food miles" are a big issue in these days of global markets. If more food can be grown closer to the end user with minimal environmental impact the savings in transport costs (both financial and environmental) can be enormous. Producing food locally using hydroponics is more sustainable than relying on imported organic produce.