Hydroponics involves growing plants in water that contains dissolved nutrients instead of soil. Plants are placed in a sterile medium like sand or perlite so the roots can support the plant. Water that is enriched with nutrients flows over the growing medium and becomes available to plants. Greenhouses with a controlled environment are essential for growing plants using hydroponics.
In the 19th century, scientist Jean Boussingault found that plants could survive in water when given the nutrients needed to survive as long as the water remained oxygenated. The idea gained popularity in places where food crops could not grow and was used extensively in World War II to grow vegetables for troops on the Pacific Islands. Now, vegetables and cut flowers grown hydroponically make up a growing portion of the market for agricultural products.
Hydroponics is a significant discovery for agriculture because plants can be given exactly what nutrients they need when they need it, creating a perfect growing environment. Growing plants in soil is challenging because amendments are added to the soil and then interact with the soil before becoming available to plants. The grower of plants in soil has no control over how much of the added nutrient is available to each plant. Also, soil harbors many types of diseases that can affect plant health and yields.
Growing plants using hydroponics means a drastic decrease in herbicide and pesticide usage. Chemicals used to control pests are toxic to nontarget plants and animals. Also, these chemicals enter the ground in runoff and can contaminate drinking water.
The amount of land needed for growing hydroponically is much smaller than that needed for growing plants in soil. Water can be filtered and recycled, decreasing the amount of water needed. Yields per acre can be increased as much four times using hydroponics.
Hydroponics allows plants to grow in geographical areas where they are not suited, such as the desert or cold climates, because greenhouse conditions can be carefully controlled.
A hydroponic system is expensive to install and takes some knowledge of plant physiology. Water pH and nutrients as well as lighting and temperatures in the greenhouse need to be constantly monitored. Heating and cooling of greenhouses can increase the cost of a hydroponic operation.
It is possible that one day all vegetables you buy will be produced hydroponically as the price of production continues to decrease. However, not all varieties of vegetables are suitable for hydroponic production. For example, heirloom tomatoes that depend on warm sun and soil elements to concentrate the sugars in the fruit don't always taste the same if grown under hydroponic conditions.