10 Myths About LED Grow Lights You Should Stop Believing

By Luis Rivera
Published: April 28, 2017 | Last updated: May 4, 2021 09:18:41
Key Takeaways

LEDs are great for growing potent cannabis plants. In this mythbusters article, we set the record straight on LED grow lights.

LED stands for light-emitting diodes, and those diodes are used for the making of light bulbs, lighting panels, lamps, and other luminous devices. Due to their efficiency, LEDs are often found in both commercial and domestic fields including healthcare, construction, agriculture, urban infrastructure, and gardening, among many others.


They provide many benefits over regular lights:

  • Energy efficiency
  • Long-lasting life
  • Low heat output
  • Compactness
  • Stimulated plant growth
  • Adjustable wavelength

LED lights function differently from regular light-emitting devices. They send an electric current via a special semiconductor, which can be made from various materials. The current then stimulates electrons that make a small light bulb shine very brightly. Depending on the type of material the semiconductor is made from, the wavelength of the light changes.


Read also: The Influence of Spectral Light Quality on Cannabis Plant Growth

This is precisely why LED lights are perfect for growing cannabis plants, which require different light throughout each stage of development. LED grow lights are among the most intensely developed technological aids in plant growing, enabling both professional farmers and casual home growers to provide their plants with the best lighting conditions.

However, there are many misconceptions regarding LED grow lights and we are here to illuminate the right from wrong.


1. LED lights are not sufficiently bright.

It is commonly mistaken that wattage and brightness are correlated. Many assume that if a light consumes more watts then it also shines brighter, but that's not the case.

A standard LED light bulb needs only about 8 watts, whereas a regular light bulb needs at least 10 times that wattage in order to produce the same amount of lumens. Watts are used to measure energy consumption and are not a metric for light efficiency. Especially when it comes to growing plants, which takes into account other factors such as wavelength.


Cannabis plant under an LED grow lightUnlike other types of grow lights, LEDs do not burn a filament, but instead pass light through semiconductors to create their spectrum.

2. LED lights are expensive.

Although LED lights are more costly per single unit, in the long run they prove to be extremely economic. Consider this: a cheap incandescent light can last for about 1,200 hours, a regular fluorescent light has an average life expectancy of about 20,000 hours, and an LED light can last up to 50,000 hours, which amounts to more than 10 years. It's quite easy to deduce that the latter option proves to be cheaper in reality, but here are some more detailed calculations proving the point.

3. LED light is harmful.

Unfamiliarity with LED lighting might make some people think that it is harmful to the eyes, but this is not true. As any other product released for public purchase, LED lighting has met safety standards. A study by CELMA shows that LEDs are perfectly safe and pose no harm whatsoever if used properly. Naturally, staring at an LED bulb for a long time might cause some negative effects, but the same holds true for any source of light.

4. LEDs are made using dangerous components.

Following the aforementioned matter, we are going to get another LED safety concern out of the way—hazardous components. As we already said, LED manufacturers must abide by strict regulations and there is no mercury, lead or other harmful materials used in the process. In fact, LEDs are ecologically friendly and recyclable, proving that they are truly the future of lighting.

5. LED lighting is not fully developed.

LEDs emit mainly blue and red light, comprising the so called Photosynthetically Active Radiation spectrum that plants need in order to photosynthesize. Grow lights are also made in a way that helps protect plants by using a special sink, limiting heat emission. This makes the lights more energy efficient but also helps prevent damage from high temperature—definitely not something you'd call underdeveloped technology.

Read also: Red Light, Blue Light: Balancing LED Efficiency with Performance

6. LED lights can't damage plants.

We must mention that although LEDs are perfectly safe and developed in a way that makes harming plants very difficult, it is not impossible. Many think that due to the low heat output of LED lights, their exact placement near to plants is not important, but that is wrong. If the light is too close it can prove to be too much for the plant to process, triggering a defense mechanism and leading to what`s called photoinhibition. This might cause photo-bleaching and turn the plant's leaves white.

7.LED lights produce no heat.

Although they are incredibly efficient, LED lights still produce some heat that needs to be properly managed. This is a result of the energy being transformed and heating up the lamp. Each watt of electricity produces some amount of heat regardless of LEDs output efficiency. For example, an LED bulb that consumes 8 watts would generate a heat of 27.28 Btu.

Cannabis plants under an LED grow lightLEDs have long service lives, with bulbs lasting from 50,000 to 100,000 hours of continuous use.

8. LED lights consume a lot of power.

The lighting industry has undergone drastic improvements throughout the years in order to provide the powerful full spectrum LED grow lights available on the market nowadays, but still their power efficiency is an uncertainty to many. There are even claims that half of the energy is lost in the lighting process as heat. This is false. It all depends on the specifics, but in general LED lighting has become 60% more energy efficient during the past 10 years and uses up to 80% less energy than regular lighting.

9. LED lights are very fragile.

It's natural to be concerned about durability when you hear the word “light,” but despite the superior complexity of their nature LED lights are far sturdier than regular incandescent lights. An LED light consists of a small chip closed inside an epoxy resin capsule and uses a semiconductor as opposed to neon gas, putting all fragility issues to rest. Furthermore, there are no glass particles, improving LEDs resistance to shaking, vibrations and heat.

10. Lumens are quintessential to photosynthesis.

LED grow lights are designed specifically to aid plants, not to be luminous or bright. Therefore, is is not the lumens that determine how much a light stimulates a plant's growth. Lumens are used to measure light as perceived by the human eye. Plants need a different type of light which we cannot see and thus cannot measure based on brightness.

Now that you have more information about LED grow lights you can hopefully understand that this is the way of the future. They are a great aid in the growing of plants, providing better yields and energy efficiency, but also bring benefits to many commercial and domestic fields.

Read next: How to Set Up Your LED Grow Light for Growing Cannabis


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Written by Luis Rivera

Profile Picture of Luis Rivera

Luis Rivera has more than 20 years of experience in global market expansion, business development, mergers and acquisitions, business re-engineering, finance and investor relations of software companies. He is passionate about technology, spectral science, indoor farming, food production, automation, and more. Since 2015 he has been the president of Advanced LED Lights, a leading LED grow lights manufacturer based in Hiwasse, Arkansas. When not at work, Luis enjoys swimming, yoga, and growing grapes and flowers in Sonoma, California.

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