High-pressure sodium grow lights (HPS) emit an orange-red glow which triggers hormones in plants that increase flowering and budding. They are mainly used in the second (or reproductive) phase of growth in an effort to mimic the autumn sun. When used during the vegetative phase, plants will usually grow a little quicker. However, growing under HPS lighting alone will produce taller plants with a longer internodal length as opposed to plants grown under metal halide in the vegetative phase.
The big difference between the high pressure sodium lights and their HID counterpart,
Metal Halide, is that the HPS lighting provides more of the red spectrum while the
MH emits light from the blue spectrum. High pressure sodium bulbs are very efficient,
producing up to 140 lumens per watt and radiating six times more light per watt of
consumed energy than incandescent bulbs. Put another way, a 1,000 watt HPS bulb
emits as much light as 100 incandescent 100 watt bulbs. Also, HPS bulbs have a very
long life span with average usage twice that of metal halides. The only issue is that
after about 18,000 hours (or 2 years) of use, they will begin to gradually produce less
light while drawing more electricity than their rated watts.
You may also want to check out the color corrected HPS bulbs which provide
improved growing and efficiency, and contain a more balanced color spectrum.
HPS Light Output and Growing Area
When selecting the right high pressure sodium lighting system, be sure to consider
the grow area, reflectors and of course, the proper ballast. All of these factors
contribute to the quality and quantity of your fruits, flowers, veggies and herbs.
Advantages and Disadvantages of High Pressure Sodium Grow Lights
The main benefit of high pressure sodium grow lights is their ability to improve the
flowering, fruiting and budding of a plant, and most importantly, increased yield size.
Theses lights are also extremely efficient (low energy to light ratio)
The big problem with High Pressure Sodium grow lights is that they produce a great
deal of heat. This creates an environment that is conducive to insects and possible
diseases on the plants. To reduce the amount of heat around the grow area, special
air cooled enclosures and reflectors can be used.
HPS Lighting – Helpful Tips
How high to hang the lights: Because of the intense heat that is given off by these types
of lights, you will want to hang them according to their size. Smaller systems, like the
100 and 250 watt lights, should be hung about 24 to 36 inches from the tops of the
plants. Medium systems likes the 400 and 600 watt lights should hang around 48
inches from the tops of the plants. The big boys, 1,000 watts and higher, should be
hung at least 4 to 6 feet from tops of the plants.
How long to run the lights: While this varies depending on the type of plant, most
plants and vegetables need roughly 10 to 12 hours of light in order to promote proper
growth. However, plants that produce flowers and/or fruits can grow well with as much
as 16 hours a day of light.
© 2011 CityGrown. All RIghts Reserved. Site Design by KFP