HID - High Intensity Discharge Lights

HID grow light bulbs are a sealed tube filled with gas that creates light when the gas is ignited by two electrodes that arc current between them.

MH - Metal Halide

MH grow light bulbs should be used for the vegetative phase as they give off a blue to white spectrum

HPS - High Pressure Sodium

HPS has a red or orange tint and is used primarily in the flowering phase of your plant's life.

CMH - Ceramic Metal Halide

CMH grow light lamps are a relatively new source of HID light that is a variation of the traditional Metal Halide HID lamp.