How long do HPS bulbs last? What is a HPS Light? Invented in 1964, HPS stands for High Pressure Sodium. It’s a light technology that has shaped how we cultivate indoor plants in a huge way. HPS bulbs consist of a narrow arc tube supported by a frame in a bulb. To improve efficiency, the arc tube is kept at an extremely high pressure. Sodium, mercury and xenon are usually used inside the arc tube in order to improve the light spectrum. The most common way to start the bulbs is with a pulse start. This pulse starts an arc through the xenon gas and the lamp turns sky blue. The arc then heats the mercury which then lights up, giving the bulb a bluish color. As the bulb heats and the sodium starts to vaporize it strikes an arc over 450° F (240° C). The sodium is then mixed with other impurities to create a more “white” light. Mercury helps add a blue spectrum light to the pure yellow of the sodium.
Single versus Double Ended HPS Bulbs The next important consideration you have to make is choosing between single and double ended high pressure sodium grow lights. Single-ended HPS grow lights have been in the industry for decades. These lights use the normal Edison screw thread, which is easy to install. Double ended HPS lamps are considered to be more efficient. Basically, twenty-five to thirty percent more resourceful, providing you with a higher PAR. Double ended models are known to be long-lasting, and they will still have roughly 90% of their output after repeated and long-term use. The major drawback of these lamps is that they cost more, and you need to specify double ended reflectors that are pricier than single ended reflectors. Regardless of how efficient double ended designs are, our recommendation is to buy a single ended HPS grow light, which is cost-effective and easier to maintain.
How long is a HPS bulb good for? A better comprehension of why and when your light system requires light bulbs replacement can help you keep a high level of photosynthetically active radiation all the time in your grow room. That will eventually maximize the production and performance of your garden. Of all the things you have to master when growing marijuana indoors, understanding how the light energy diminishes is imperative of keeping an efficient grow space. By placing your plants close to the source of light, you’ll automatically get the most out of your light system. Yet, the distance between plants and light bulbs isn’t the only thing to take into
consideration with regard to the light diminishing. This is why you need to know how long the HPS bulbs are good for. All light technologies are depreciating over time. That reduces the light energy which is usable for plants. Why does it happen? When the HID lampsare first fired, they receive a tremendous voltage pulse. That blast of initial voltage damages the lamps a bit every time you turn on the lights. After a while (usually after 8 months), the repetitious process of firing the grow lights makes the arc tube change its properties. That doesn’t only cause a color shift within the spectrum output but also lower the intensity of lights. Your task is to replace the light bulbs in your light system from time to time to avoid this reduction. This raises the question: What is the right time to replace light bulbs? That depends on the type of lamps you use in your light systems. Let’s say you use metal halide (MH) and High Pressure Sodium (HPS) lights. If so, keep in mind that the depreciation rate of MH bulbs is fast compared to HPS bulbs. That’s because of the specific components and metals in MH lamps. Metal halide bulbs will be depreciated about twice as much as HPS bulbs after around 20000 hours of use. If you’re using MH grow lights in your system, be sure to replace these bulbs after 6-9 months of use. As for HPS bulbs, they depreciate due to the operation temperature, initial voltage, and the age. Their lifespan also depends on the type of ballast used. They usually start degrading in the blue specter first because of the compounds used. Nevertheless, HPS light bulbs degrade slightly slower than metal halide lights. They typically require replacement after 12-14 months of continuous use.
WHEN TO REPLACE YOUR DOUBLE ENDED HPS LAMP? 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.