A fluorescent lightbulb is a lamp that producess light by exposing a fluorescent layer to ultraviolet rays which are generated by a gas discharge in the lamp. The best known examples are the so-called fluorescent and energy saving lamps. The light output in lumens per watt is 5 to 6 times as high as in a normal light bulb.
T5, T8, PL-L lamps and CFL are the most used Fluorescent lamps for horticultural use. Fluorescent lamps are mainly used in for the growth of plants, but also in the multi-layer cultivation and for the germination of seeds. One of the biggest advantages of the fluorescent lamp is that it produces virtually no heat, making them ideal for use in confined spaces or for growing plants that like to grow in a cooler climate.