Bulbs

CFLs emit a soft light that contains the full spectrum of light. This type of lighting works well put directly over seedlings who are not getting enough light to stimulate growth. It should be used in small areas, rather than to light an entire growroom.

The metal halide (MH) lamps operate on the same principle as all HID lamps. The main difference is that the arc tube contains metallic salts (scandium and sodium) in addition to the mercury vapour and argon gas. Like all HID sources, MH lamps consist of an arc tube enclosed in an outer bulb.

HPS lamps consist of an arc tube enclosed in an outer bulb. The arc tube contains xenon (starting gas), sodium and mercury. The mercury is in the form of an amalgam with the sodium.