HID (High Intensity Discharge) grow lamps is the most common and efficient for indoor or greenhouse applications. Typically for indoor cultivation, HID lamps act as the primary light source. Whereas in a greenhouse, HID lamps can act as the primary or supplementary light source. The most common HID lamps are High Pressure Sodium (HPS) and Metal Halide lamps (MH). HPS lamps are typically used during the flowering stage. MH lamps on the other hand is used mainly for vegging stage.
A HID grow system comes with a reflector, a ballast, and the lamps. Reflectors come in all shapes and sizes, but its ultimate function is the same -- to reflect the most light to the desired area. It is important to choose the right reflector for the right size of the cultivation area!
The ballast is what controls the output of the lamp. In today's market, ballast technology has expanded into including many different features (click here for our ballast technology). Most ballast today are electronic. They are much more efficient than the older magnetic ballasts. Electronic ballasts alters the flow of electricity by a series of induction coils that are separated from each other. Whereas magnetic ballasts only have a single coil. A single coil often has inconsistent flow, resulting in the lamp flickering. The electronic ballast is much lighter in design compared to magnetic ballasts, is consistent, can change the frequency of the output without changing the volt, and can be used in parallel with multiply lamps.
Until recently, there were only singled ended HID lamps. They are screwed in just like a regular light bulb that you see at home. Now, there are double ended lamps that attach themselves onto the fixture on both ends (click here to see our HPS lamps). Double ended lamps are 25-30% more efficient than single ended lamps. Most cultivators are using double ended lamps, although there are a portion of hobbyist cultivators still using single ended lamps. HID lamps are very hot, so the temperature inside the grow area must be cooled. However the lamps must not be cooled directly , meaning blowing air on the lamps, as this would cause the lamp to lose efficiency. The lamps must also not be placed too close to the plant, causing decrease in light uniformity, and more importantly the plant will be burnt! Remember light uniformity is just as important as light intensity!