- Also called:
- aquaculture, nutriculture, soilless culture, or tank farming
- Related Topics:
- Vertical farming
- Aquaponics
- crop production
- On the Web:
- University of Minnesota Extension - Small-scale hydroponics (Oct. 17, 2026)
Hydroponics
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What is hydroponics?
Hydroponics is a soilless method of growing plants, where roots are immersed in a water solution containing essential minerals, or kept moist by such a solution in a sand medium. This technique allows plants to be grown indoors, even in densely populated areas, regardless of climate.
Hydroponic systems save labor through automated watering and fertilizing. They also use less water than conventional methods, and plants face reduced root and nutrient competition with fewer pests, enabling closer planting. A variety of crops including lettuces, spinach, tomatoes, strawberries, and cannabis can be grown using hydroponics. Some systems integrate aquaculture, using nutrient-rich wastewater from fish farming to nourish the plants.
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How is hydroponics different from growing plants in soil?
Hydroponics is a method of growing plants without soil, using water solutions containing essential minerals. Unlike soil-based cultivation, hydroponics allows for automatic watering and fertilizing, saving labor. Hydroponic systems can be set up indoors, even in densely populated areas, and use significantly less water than traditional methods.
However, hydroponics involves high installation costs and requires frequent solution testing. It also demands a steep learning curve, and system failures can be detrimental. While hydroponic plants avoid root and nutrient competition and have fewer pests, yields are comparable to soil-grown crops. Some hydroponic systems, known as aquaponics, utilize nutrient-rich wastewater from aquaculture to nourish plants.
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What are the basic parts needed for a hydroponic system?
A hydroponic system eliminates soil, using water and nutrients to grow plants. Basic components include a reservoir to hold the nutrient solution, a growing tray or container to support the plants, and a pump to circulate the solution. An air pump and air stone aerate the solution, while a timer controls the pump. The growing medium, such as rock wool or clay pellets, anchors the roots. Essential nutrients like nitrogen, phosphorus, and potassium must be dissolved in the water.
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How do plants get nutrients in hydroponics?
In hydroponics, plants get nutrients from mineral salts dissolved in water, rather than from soil. The elements absorbed as salts include micronutrients like iron, manganese, boron, copper, zinc, and molybdenum. The principal elements that must be provided as dissolved salts are nitrogen, phosphorus, sulfur, potassium, calcium, and magnesium.
The fertilizer solution is composed of agricultural or horticultural fertilizer-grade chemical compounds containing varying amounts of nitrogen, phosphorus, and potassium, the major elements necessary for plant growth, and various trace, or minor, elements, such as sulfur, magnesium, and calcium. The concentration of the solution and frequency of pumping are increased as the plants grow.
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What types of plants are commonly grown using hydroponics?
Many vegetables and florist crops can be effectively grown using hydroponics systems. Commonly grown crops include lettuces, spinach, kale, tomatoes, peppers, cucumbers, radishes, strawberries, and cannabis. Hydroponic systems are frequently used in vertical farming, where crops are grown indoors in stacked layers without soil.
Some systems, known as aquaponics, utilize nutrient-rich wastewater from aquaculture to fertilize hydroponic plants. Freshwater fish, such as tilapia, and crayfish are common aquatic animals utilized for these hybrid systems.
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What are some benefits and challenges of using hydroponics for horticulture?
Hydroponics offers several benefits for horticulture, including reduced water usage, climate control, and the ability to grow crops in otherwise unusable areas. Plants experience less competition for nutrients and encounter fewer pests, enabling denser planting.
However, hydroponic systems also present challenges such as high initial costs and the necessity for frequent solution testing. A steep learning curve and vulnerability to equipment failure or power outages can also impact crop health. Despite these challenges, hydroponics can achieve crop yields comparable to traditional soil-based agriculture and may be certified as organic.
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Hydroponics, the cultivation of plants in nutrient-enriched water, with or without the mechanical support of an inert medium such as sand, gravel, or perlite.
Setup
Plants have long been grown with their roots immersed in solutions of water and fertilizer for scientific studies of their nutrition. Early commercial hydroponics (from Greek hydro-, “water,” and ponos, “labor”) adopted this method of culture. Because of the difficulties in supporting the plants in a normal upright growing position and aerating the solution, however, this method was supplanted by gravel culture, in which gravel supports the plants in a watertight bed or bench. Various kinds of substrates have been used successfully, including rock wool (molten rock that is spun into fibers), fused shale, clay pellets, coconut coir, rice husks, granite chips, sand, pumice, perlite, and vermiculite. Fertilizer solution, often derived from fish or duck excrement or synthetic fertilizers, is pumped through periodically, the frequency and concentration depending on the plant and on ambient conditions such as light and temperature. The solution drains into a tank, and pumping is usually automatic.
The fertilizer solution is composed of different agricultural or horticultural fertilizer-grade chemical compounds containing varying amounts of nitrogen, phosphorus, and potassium—the major elements necessary for plant growth—and various trace, or minor, elements, such as sulfur, magnesium, and calcium. The solution can be used indefinitely; periodic tests indicate the need for additional chemicals or water. The chemical ingredients usually may be mixed dry and stored. As the plants grow, concentration of the solution and frequency of pumping are increased.
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Crops and applications
A wide variety of vegetables and florist crops can be grown satisfactorily with hydroponic systems. Common crops include lettuces, spinach, kale, tomatoes, peppers, cucumbers, radishes, strawberries, and cannabis. The model organism Arabidopsis thaliana is also sometimes grown this way for genetic research. Hydroponic systems are commonly used in vertical farming operations, where crops are grown indoors in vertical, stacked layers with no soil.
Some systems, known as aquaponics, use nutrient-rich wastewater from aquaculture to fertilize hydroponic plants. Freshwater fish, such as tilapia, and crayfish are common aquatic animals utilized for these hybrid systems.
Advantages and disadvantages
Hydroponic systems have a number of advantages and disadvantages compared with cultivation in soil. The principal advantage is the saving of labor by automatic watering and fertilizing. Hydroponic systems can be set up indoors in places that would not normally be available for the growing of plants, such as in densely populated areas, and have even been studied as a potential method of crop production aboard spacecraft. Climate is not a factor, and hydroponic systems use dramatically less water compared with conventionally grown plants. The plants also have less root and nutrient competition than those grown in soil, and they have significantly fewer pests, so individuals can be planted more closely together.
The disadvantages are high installation costs and the need to test the solution frequently. There is a steep learning curve to hydroponics, and small errors can affect the whole crop. The systems are also very vulnerable to equipment failure or power outage, which can kill the plants within a few hours. Yields are about the same as for soil-grown crops.
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Hydroponic crops are allowed to be certified as organic in many places, including in the United States. Critics have pointed out that hydroponic plants lack interaction with a soil microbiome and have argued that soil health is a critical part of the organic farming movement.