What is the lifespan of HPS grow light

HPS Grow Lights
Best hps grow light or High pressure sodium lamps is a High intensity discharge (HID) form of lighting that is commonly used as indoor grow lights for hydroponic production of plants, flowers and vegetables.
The HPS light operates when an electrical current is run through an arc tube that has been filled with a gas. In this case the gasses found within a HPS globe is a mixture of sodium and an inert gas Xenon. The Xenon is used as a starting gas in the high pressure sodium lamp. The current and temperature increases in the arc tube until it reaches a high pressure operating state.
High pressure sodium or HPS lamps have a higher efficiency than the older style of metal halide or mercury vapour lamp, reaching around 150 lumens per watt or 90,000 lumens for a 600w HPS lamp and around 55,000 lumens for a 400w HPS lamp.
HPS lamps have a spectral range from 570nm up to 750nm which are the yellow, orange and reds. With some versions of the HPS lamps they have been tuned more for horticulture and have spikes in the blue at around the 450nm to 500nm range this makes them a fantastic choice all around for horticultural lamps to be used as indoor grow lights and hydroponic lighting. These grow lights have had their spectrum optimized to provide the exact spectrum for use as an indoor grow light.
All lamps have a limited life span, as the sodium is highly reactive this leads to a slow loss of gas over time and this eventually will lead to the lamp cycling.
As a result the lamps will start to overheat during operation which increases the pressure in the arc tube and more than normal voltage is required to maintain the discharge from the arc tube. The expected life span of a HPS is around 20,000 hours but it is recommended that the lamps be changed after around 3000-5000 hours, as they will have lost significant lumen output.
In conclusion HPS grow lights have an ideal spectrum for flowering plants. HPS grow lights are cheap to purchase compared to LED grow lights and they are a lot more efficient than older style metal halide grow lights. HPS grow lights are the indoor grow light of choice for most hydroponic grow light kits that are purchased today.
Characteristics of HPS bulbs
HPS bulbs operate on an entirely different electrical principle than MH bulbs. Iff the power surges or the light is turned off for any reason, the gases in the arc tube will need between three and 15 minutes to cool before the light can be restarted. But because starting a HPS bulb requires a tremendous amount of initial voltage—which stresses the system—turning the light on and off more than once a day is not advised because it can shorten life span of the bulb.
Unlike standard MH bulbs, HPS bulbs can be positioned at any angle without having to worry about the arc tube bending. So, there is no specific designation among HPS bulbs for horizontal, vertical or universal use, as there is with MH bulbs. In addition, not only are HPS bulbs the most efficient HID bulbs, they have an extremely long lifespan of approximately 24,000 hours, or up to five years of operation running 12 hours per day.
Over time, the sodium slowly escapes from the arc tube over long periods of daily use, and the sodium-to-mercury ratio within the arc tube changes—which eventually causes the voltage in the arc tube to rise beyond the point that the ballast is able to sustain. As a result, the light will eventually reach a point where it will start, warm up to full intensity and then extinguish repetitively. This is your indication that the bulb has reached the end of its lifespan. But in order to maintain peak efficiency in your garden, HPS bulbs should be replaced every 18 to 24 months, even though they have life spans more than twice that.
The main reason professional indoor growers use HPS bulbs for the flowering stage is that when a cannabis plant reaches the pre-flowering stage, hormones within the plant’s cells inform the plant that it has reached the age of sexual maturity. This causes the plant to cease concentration on the production of vegetative cells and instead start the process of preparing itself to produce seeds.
Because HPS bulbs produce a color spectrum that peaks in the yellow, orange and red wavelengths, they stimulate floral hormones within the plant and promote the formation and maturation of the buds. Thus, when the light cycle is reduced from 18 hours to 12 hours to induce flowering and the bulbs are changed from MH to HPS, the color spectrum emitted by HPS bulbs serves to enhance the process of inducing flowering. Then it continues to enhance the maturation of buds throughout the flowering stage.
What is the lifespan of HPS grow light
Lighting is often an overlooked aspect of indoor gardening. If there is a noticeable drop in yield, many growers look at their nutrients, room temperature or humidity as the cause. In most cases, the loss in yield is directly due to not keeping a consistent grow lamp replacement schedule.
It is important to understand the limitations of DE HPS grow lamps and not buy into the hype that says they will grow effectively for two years. The facts and the physics do not support this statement.
12 Hours On – 12 Hours Off – 12 Months and Replace
Growers using DE HPS should replace these lamps once every 12 months to maintain consistent yields from crop to crop. Many growers have been told DE lamps will last for two years. This is not true. DE lamps can operate for many, many years but their effective growing window is 12 months when using a 12-on, 12-off flowering light cycle.
Growers using light meters to measure Photosynthetic Active Radiation (PAR) in micro moles (µmol) will only see a 5% loss in intensity after one year of use. Since the light meter is only measuring PAR (click here to learn about PAR) between 400 and 700 nanometers, it does not tell you the lamp has lost over 10% of the total amount of light energy produced by the DE lamp. The spectral quality of the light at this point has dropped below its initial ability to produce high yields.
To the human eye, the lamps still look as bright as they did the day they were installed. However, the overall amount of light and the quality of the spectrum available to the plants has dropped significantly and this will produce lower yields affecting your bottom line.
By the time you see lower yields it’s already past time to replace your lamps.
So, remember: 12 – 12 – 12.