Hydroponics is the science of growing plants without soil, using a nutrient solution to provide the nutritional requirements. Hydroponic culture can be very simple; a bucket full of sand and a watering can to deliver the nutrient solution can support a thriving tomato plant. Hydroponics operations may be incredibly complex, as well, employing computerized feeding, watering, and monitoring systems, electronic sensors, and growing media made from advanced, man-made materials.
The most important piece of hydroponic equipment is the nutrient solution delivery system. It can be as simple as a watering can or a very complex system using computers to coordinate pumps, valves and gates to circulate the nutrient solution to the plants. Such systems usually have a reservoir where the nutrient solution is collected after being given to the plants. The nutrient solution may be pumped to the plants periodically or continuously delivered by means of a drip system which constantly delivers a trickle of the solution.
The nutrient solution is an important part of any hydroponics system. Nutrients may be tailored to specific plants or crops, and this is usually the case in large commercial operations. General nutrient solutions exist which will support almost any plant, but most growers use formulas specific to the plant or crop being grown.
Computerized sensors may monitor the solution and continually make adjustments, adding nutrients or other chemicals to maintain the optimum concentration of nutrients and pH. Computers may also be used to automate the feeding schedule, lights, ventilation and to monitor and control humidity and carbon dioxide levels. This type of hydroponic equipment is most common in large commercial operations.
Containers are the most basic type of hydroponic equipment. Containers may be individualized, one per plant, or communal. Communal containers are often large trays or troughs holding many plants. The advantage of this type of container is that it simplifies delivery of the nutrient solution since it is much easier to deliver the solution to 20 or 100 plants at once than the same number individually.
Hydroponic growing media are materials, either natural or man-made, that contain no nutrients. Gravel, vermiculite, sand, perlite, or a combination of two or more of these materials are common. Many hydroponics systems employ a type of fibrous material made from fiberglass. Other man-made materials like plastic pellets and even shredded tires are sometimes used.
Hydroponic farming is almost always done in a controlled environment such as an indoor facility or green house. For this reason, lights, fans, heaters and air conditioners are sometimes employed as hydroponic equipment. Lights for hydroponic growing operations may be very powerful, such as metal halide, high-pressure sodium, fluorescent or light emitting diode (LED) types. Specialized light bulbs are often used to closely simulate the wavelengths present in sunlight.