These lamps must be kept a safe distance from the plant so that the plant won't burn. The lamp is uncomplicated, installation costs are relatively low, a number of lamp wattages are available, external or internal reflectors are needed to maintain effeciency. Tubular Fluorescent Lamps. These are low pressure gas discharge lamps. The UV radiation is absorbed by the fluorescent powder on the inside surface of the glass tube.
Spectrial quality is determined by the phosphor selected.
These are operated by a ballast. As a sole source of light a Wide Spectrum Gro-Lux lamp should work very well. The 40 watt lamps can be located very close to the plants because the temperature of the lamps is cool. The temperature of the 8 foot VHO and HO lamps is very warm and will burn plant material if it touches the lamp. Radiant energy is produced from the discharge of electricity through a gas, the color of which depends on the kind of gas.