10 Things to Look For When Selecting an LED Grow Light

Selecting an LED grow light can be a daunting exercise, especially given the number of options and the lack of uniform labeling specifications. GrowFlux has put together this simple guide to arm consumers with some hard-hitting questions next time they encounter someone marketing "The Most Advanced Grow Light".

Without further ado:

Any reputable LED grow light manufacturer should be able to provide a third-party certified test result indicating the efficiency of their product in photonic units (PPF, measured in micromoles per watt or μmol/W). In our experience, even well-established LED lighting manufacturers have used false or erroneous numbers as recently as Summer 2018. We hope this behavior will cease when a Horticulture Lighting Label is finalized.

Image credit: Intertek

Any LED grow light manufacturer claiming to have an “optimal spectrum” is misleading its customers. This is because plants will respond to many different spectrums quite well, while no one spectrum is perfectly suited to all stages of plant growth and all cultivars. At GrowFlux, we design our products to be capable of millions of potential broad and narrow spectrum profiles without sacrificing output, allowing a cultivator to develop tailored spectrums for their unique conditions, cultivars, and desired outcomes.

Broad Vegetative 5000K with Far Red and flowering spectrum distributions. GrowFlux lights are uniquely capable of delivering both of these spectrum settings at full power.

Any modern LED lighting fixture should have a power factor of at least 0.90, which will be required by the Design Lights Consortium as they release their final policy. GrowFlux products feature active power factor correction typically exceeding 0.95.

Any horticulture lighting product should be listed for humid and wet conditions, otherwise fixtures will probably not stand up to greenhouse conditions or the sanitizing agents commonly used indoors.

Editor's Note: Remember that the growing space is alive, and stuff is always happening!

Actively cooled fixtures are able to operate at cooler temperatures and across a wider operating temperature range when compared to passively cooled fixtures. If you are considering a passively cooled fixture, look closely at the operating temperature range and ask the manufacturer how well the fixture will perform in stagnant air conditions, which can easily occur if mounted to a rack. Finally, high operating temperatures limits LED life, so be sure to ask for the expected 90% or 70% lifetime output for a passively cooled fixture. GrowFlux products are guaranteed for 90% output at 50,000 hours.

Thermal imaging of a FluxScaleTop Light fixture

If you are considering a fan-cooled lighting product, ask the manufacturer the Mean Time Before Failure (MTBF) for the fans, and what happens in the event of a fan failure. In the event of a fan failure, you should want to be covered by a warranty.

If you are considering a passively cooled fixture, discuss the conditions surrounding the fixture with your lighting manufacturer. You should have a good idea of whether you are expecting stagnant or consistently moving air around the fixture as well as the distance between the fixture and ceiling or other impermeable surfaces, as these conditions have a significant impact on passive cooling.

Even today's worst-performing LED grow lights should be able to maintain 70% output at 50,000 hours, while the highest performing lights in 2019 will reach or exceed L90% at 50,000 hours. Investing in lights with enhanced PAR maintenance extends the return on investment in your lighting system. If your manufacturer can't provide their TM-21 Energy Star calculations, stay far away.

Graph indicating L70% and L90% at 50,000 hours. Many products on the market can degrade as much as 10% in the first 2 years, threatening ROI.

PAR uniformity on the canopy is nearly as important as energy efficiency. Look for PAR maps which indicate the optimal mounting heights and PAR levels over an area representative of your intended application. For example, we offer PAR maps which show the expected PAR levels for a variety of cultivation situations and mounting heights.

LED fixtures can have drastically different optical distributions depending on the LEDs, lenses, or reflectors in the product. Manufacturers should be able to provide PAR maps representative of your cultivation conditions to help you accurately assess anticipated PAR levels.

Tunable fixtures offer the ability to tailor the light spectrum to the stage of growth or specific outcomes. If you are looking at tunable fixtures, be sure to understand how tuning the spectrum affects the output of the fixture. Most tunable LED fixtures only emit one spectrum setting at full power; any modified spectrum from the full power setting reduces overall PAR output of the fixture. Ideally you want an extended tunable range, offering you a wide variety of spectral settings at full output.

In North America, LED horticultural lighting products should be certified to UL1598, a safety standard for commercial lighting products. Products that do not comply with UL1598 are not eligible for energy rebates or Design Lights Consortium approval.

In the near future, an industry standard for a Horticulture Lighting Label will be formalized. This lighting label will require third-party lab reported total PPF as measured by an integrating sphere as well as a PAR map showing PPFD. Once such a standard is released, do not purchase an LED product that does not comply with the label, as manufacturers who do not comply with the labeling requirements will probably have performance issues that they are hiding.

If you are considering a lighting solution with remote control capabilities, make sure you consider how much time and effort is involved in networking the fixtures. Wireless grow lights can take several minutes to an hour to configure - for each individual fixture. We have also observed networked lights that require data cables and additional external controllers, which can greatly increase the cost and installation time of the solution. Finally, be sure to find out if the control solution requires a separate license fee or setup charge.

If you are considering lights with wireless control capabilities, ask your lighting manufacturer how many years they have been testing the reliability and scalability of their wireless solution. Find out what wireless protocol and frequency is being used, and determine whether the wireless connection will penetrate through the walls in your grow rooms or if you need to purchase separate networking hardware for each room. If you are looking at WiFi networked lights, consider the cost and maintenance associated with installing a network capable of supporting the number of fixtures you are installing. Ask about wireless network security. Finally, be sure to find out if the control solution requires a separate license fee or setup charge.

GrowFlux’s own AetherMesh wireless technology penetrates deep into dense buildings, providing highly secure and reliable connectivity to thousands of lights on one network.

Want to learn more about what GrowFlux has to offer? You can check out their website here. They have a ton of educational content on their blog if you want to read more before about LED grow lights as well.

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