Hydroponics is the science and technology involved in growing plants without soil. It is also known as soilless agriculture, nutriculture, or chemical culture. The word hydroponics comes from two Greek words meaning water and labor.
All plants require a mix of nutrients (nourishing substances) for proper development and growth. Land plants obtain such nutrients as oxygen, nitrogen, phosphorus, and potassium primarily by absorbing them from the soil through the plant root system. Plants in hydroponic systems, however, receive nutrients directly from water. The plants are typically grown in containers. These containers range in size from small pots for individual plants to huge tanks for large-scale growing. Plants growing without soil require the same amount of light and warmth that they would if they were growing in soil. Growers who use hydroponics indoors must provide sources of light and heat.
Scientists began understanding the nutritional needs of plants during the 1800’s. These discoveries allowed for the development of modern hydroponics. During World War II (1939-1945), members of the U.S. military grew vegetables hydroponically on islands in the Pacific that lacked fertile soil. Today, commercial farmers, researchers, and hobbyists use hydroponics to grow such produce as tomatoes and cucumbers.
Methods of hydroponics.
There are two main methods of growing plants without soil. They are water culture and aggregate culture.
In water culture, plants are suspended with their roots submerged in water that contains plant nutrients. The roots absorb water and nutrients. But do not anchor the rest of the plant. Therefore, the plants must be mechanically supported from above. The roots also take in oxygen. Therefore, air must be regularly pumped or mixed into the nutrient solution.
In aggregate culture, the roots not only absorb water and nutrients, but also anchor the plant. Instead of being placed directly in a water and nutrient solution, the roots are placed in a substrate material. This material may be coarse sand, gravel, peat, perlite, or vermiculite. A nutrient solution is either pumped up from below the roots or trickled down from above them.
There are many different kinds of nutrient solutions. A basic solution might consist of potassium nitrate, ammonium sulfate, magnesium sulfate, monocalcium phosphate, and calcium sulfate dissolved in water. Once the solution is in the tank, small amounts of manganous sulfate and a few drops of sulfuric acid would be added once a month. Small amounts of ferrous sulfate would be added once a week.
All plant nutrients must be added to the water to allow for proper growth. The nutrients a plant receives in its early growth stages will largely determine how well the plant will grow and its later quality. Only a person skilled at studying a plant’s foliage (leaves) is likely to recognize signs of poor nutrition at an early stage. By the time poor growth is noticed, it may be too late to correct the deficiency that caused it.
Importance of hydroponics.
Scientists have not conclusively proved that hydroponics can produce sturdier plants and better and larger crops than traditional methods. But growing plants without soil is an effective way to study the needs of plants. By varying the amounts of nutrients, scientists can find the best ratio for successful growth. Hydroponics also has the potential to reduce concerns over such issues as groundwater pollution, soil conservation, and pest control. It may also be useful in regions with poor soils or harsh climates.
