Hydroponic gardening is the technique of growing plants in a contained space using a nutrient-filled solution instead of soil. Because plants require the sun to create energy through the process of photosynthesis, the hydroponic gardener must recreate sunlight using artificial light. This is not a problem for greenhouses where sunlight streams through the walls and roof, however, grow lights are needed for smaller, contained gardens, such as hydroponic gardens, inside buildings. Either complete lighting systems or individual components can be purchased.
What are the Types of Lights Used?
The different types of lights used in hydroponics include fluorescent, which are suitable for low-growing plants, such as lettuce, which needs indirect light and high-intensity discharge (HID) lights. Two types of HID lighting used in hydroponics are high-pressure sodium lights, which are used to grow flowers, and metal halide lights, which are used to grow vegetables, according to "How To Hydroponics" by Keith Roberto.
Light-emitting diodes (LED) are new to the hydroponics market and are high-intensity, energy-efficient lights that consume a fraction of the power of metal halide lights but, unfortunately, are extremely expensive.
What are the Advantages and Disadvantages?
HID lights are powerful, and they cover a wide area so plants do not have to be right under the light to receive the benefits. Another advantage is that HID lights mimic the sunlight that plants need to grow. High-pressure sodium lights emit colors in the red-orange range, which imitate the fall sun, and blue is emitted by metal halide lights, mimicking the sun in summer.
The disadvantages of HID lights include high heat output, poor energy efficiency and high operating cost in comparison to fluorescent lights. Each light is furnished with a ballast that supplies, controls and limits voltage to the light. Hydroponic gardeners usually use both types of HID lights and the ballasts are usually not interchangeable and have to be bought separately, which adds to the cost.
Is an Electrician Necessary for Installation?
An electrician is not necessary to install HID lights as long as the ballasts are assembled, according to "Gardening Indoors with HID Lights" by George F. Van Patten and Alyssa F. Bust. Ballasts are equipped with a metal box that protects the interior wires. If the wires are on outside of the box, a qualified electrician must install the system. Additionally, ballasts run very hot, so do not install them in another box. Check the temperature by placing an unlit match against the side of the ballast and if it lights, have the ballast checked by an electrician.