Hydroponics is a method of cultivating plants without the use of soil. The use of hydroponics is an effective way of growing plants when fertilized farmland or space is not available. Instead of receiving nutrients from damaged or unbalanced soil, plants receive all the nutrients they need from a nutrient solution that is applied to the plants' roots.
A properly balanced nutrient solution is essential to the success of a hydroponic garden. Hydroponic nutrient solution is also the plant's fertilizer, supplying all 13 elements essential to a plant's growth. Nutrient solutions are available from garden centers and supply mixing instructions on their label. Mixing at the correct dilution rate keeps the nutrient solution's pH level at the correct level, between 5 and 6. Different nutrient solutions are available for different stages of plant growth, such as when the plant is starting out or when it is fruiting.
Hydroponic systems are split into two main groups: water culture systems and aggregate systems. Water culture systems supply the nutrient solution directly to the roots of the plant. Systems included in the water culture group are the nutrient film technique, aeroponics and aeration. Aggregate systems supply the nutrient solution to the plant roots by saturating a growing medium that holds the plant roots in place. Aggregate systems include the flood and drain method, the trickle feed method and tube culture.
Growing media, or substrate, is sometimes used in the construction of a hydroponic system. Alabama Cooperative Extension says the basic requirements for a growing media is that it hold the plant's root system, is inert, provides proper aeration, is free of insects and disease and will not break down over time. Commonly used media includes perlite, vermiculite, rock wool and coarse sand.
Most plants require between 8 to 10 hours of sunlight to grow properly. Hydroponic systems set up inside must have an artificial light source to supply the correct amount of light for plants to grow. Virginia Cooperative Extension recommends metal halide lamps, sodium vapor lamps, gro-lams, or fluorescent lamps in conjunction with incandescent light bulbs to supply light to plants. It is important that air is circulated throughout the hydroponic growing area to move the leaves and prevent burning. Bulbs with different intensities are available for varieties that need alternating intensities of light.
Temperature requires regulating when growing hydroponically indoors. Most plants grow best when in a temperature of between 70 and 80 degrees Fahrenheit during the day and 60 to 70 degrees during the night for warm season plants, and 10 degrees lower for cool season vegetables, says the Alabama Cooperative Extension. Grow lamps will provide heat to the plant, and the amount of heat supplied by the grow lamps is usually indicated by the bulb intensity. It is important to regulate the growing area temperature to compensate.