High Intensity Discharge Grow Lights (HID)
High Intensity Discharge Grow Lights, or HID Grow Lights, are lights made of a sealed, outer glass bulb that houses an arc tube filled with conductive gases and metals. An intense light is created when an electric arc passes through the arc tube. Electrodes located on the ends of the arc tube, create the electric arc.
The two main types of HID grow lights used by indoor growers are High Pressure Sodium (HPS) grow lights and Metal Halide (MH) grow lights. Regardless of type, the overall mechanics and operation of the different lights are the same; it’s the inner composition of the arc tube that determines the type. Read more about HID lights.