High Pressure Sodium (HPS)
Definition - What does High Pressure Sodium (HPS) mean?
High pressure sodium (HPS) is a type of light bulb commonly used as a grow light in the production of cannabis. HPS bulbs, along with other types of grow lights such as metal halide (MH) and mercury vapor (MV) are known as high intensity discharge (HID) lights.
High pressure sodium bulbs emit light primarily from the yellow to red parts of the visible spectrum. HPS bulbs are sometimes available as a conversion bulb, meaning they can be operated in a metal halide ballast, or vice-versa.
Hydrolife explains High Pressure Sodium (HPS)
High pressure sodium lights are typically used by cannabis growers during the budding and flowering phases of growth. They are often used to supplement light in greenhouses that receive natural light, or alternately with MH lights in grow areas without natural lighting.
Typically, MH lights are used during the vegetative growth stages and the the grower switches to HPS bulbs once buds are due to form.
HPS bulbs produce a lot of heat. As such, they are best used in grow rooms with high ceilings and proper air flow and ventilation. If placed too close to a cannabis crop, HPS lights can burn the leaves.
For a long time, HPS bulbs were the bulb of choice for many marijuana growers. However, newer technologies like LEDs and CMH are providing more competition for HPS manufacturers. In an effort to compete, HPS manufacturers now offer double-ended lighting technology, which are more powerful and last longer than their single-ended counterparts.