8 Things You Should Know About The Common LED Grow Light Myths

 LED Grow Lights are becoming very popular and they are a good choice if you are buying a new grow light system or upgrading your old florescent fixture. This post about LED grow light myths will save you time and money.

As with any new technology, there are many myths about LED grow lights. Some are started because of a lack of knowledge by the general public, but many are started by manufacturers who are trying to sell their products. Some of them prefer to keep us in the dark so they can make outrageous claims, but the better companies don’t do this. We need to do our part and become educated consumers so that we can properly evaluate both the message being broadcast and the product itself.

1: Watts Indicate Brightness

With incandescent and florescent lights, watts were a good measure of the brightness of a light. A 100-watt bulb was always brighter than a 60-watt bulb. Not so with LED. Lower wattage can produce more light.

The watts rating on a LED grow light tells you how much electricity it will use, and therefore the ongoing cost to run the light, but it tells you very little about how bright the light is, or how suitable the light is for growing plants.

2: PAR is a Measure of Light Intensity

You will have trouble finding a PPFD value for most lights. LED shop lights will not provide this value because they are not being sold specifically for plant growth. Many LED grow lights will not give you this value because they want to sell you on watts and give you that value instead — don’t buy from these companies.

The other reason you will have trouble finding a PPFD value is that many people equate PPFD to PAR. They provide PPFD values but call them PAR values. They just don’t understand what PAR means — it is a measure of light quality, not intensity.

If the product does not advertise a PPFD value but does show you a PAR value — you can usually assume they are the same thing. The units should be μmol/m2/s.

3: LEDs Are 100% Efficient

A common misconception of LED lights is that they are 100% efficient at turning electricity into light. Granted they are more efficient than older technology like incandescent and fluorescent lights, but they are not 100% efficient.

4: LEDs Don’t Produce Heat

In theory LED lights could convert all of the electricity into light, but that only works in storybooks. In real life, an LED converts 20% or more of the electricity into heat.

A light fixture containing 100 individual LED bulbs creates a lot of heat. The lights are designed so that most of this heat comes out the back of the fixture, directing it away from the plant. Larger units also contain fans that blow the heat away. This is important since heat shortens the life of LED bulbs.

5: Higher Watt Bulbs are Better

LED bulbs — the single units that give off the light, are available in various watt ratings. 1, 3, 5, 10-watt bulbs are common. This leads to another myth. It is common to see the claim that a 3-watt unit does not produce as much light as a 5-watt unit — so the 5 must be better. It is not that simple.

Most bulbs are not run at 100% efficiency. Higher wattage bulbs tend to be run at lower efficiency levels since they produce too much heat at higher efficiency. So a 5-watt bulb may be giving the same amount of light as a 3-watt bulb.

The wattage of the bulb does not tell you very much.

A DIY grow light using COB lights, spaced farther apart than on commercial units. 
A DIY grow light using COB LED lights, spaced farther apart than on commercial units.

Higher watt bulbs are newer technology and generally cost more. They may also have a shorter life. Given the current technology, your best bang for the buck is a 3-watt bulb. It is a good compromise between efficiency, reliability, and cost.

A newer technology called COB LED (chip-on-board LED), is more efficient, has a longer life, but is more expensive. At the moment, I think the technology is too new and still has issues. One potential benefit of this technology is that it allows the manufacture to make longer light tracks, similar to a traditional 4 ft fluorescent fixture. In that configuration, it would cover a larger area for home use. Manufacturers have not taken advantage of this feature, maybe because of higher shipping costs for a larger unit, but there are some DIY systems worth looking into.

6. LEDs contain hazardous materials

Another misconception about LED lighting is that LED lights contain many hazardous materials such as mercury, lead, and others, but this myth is so far from the truth. LED lights are completely safe! According to a study published in the Environmental Science & Technology journal, almost all LED lights are not hazardous. The only exception is low-intensity red LEDs because they leach a small amount of lead. But this lead leak barely exceeded the regulations and therefore is nothing to worry about. On top of that, LEDs are also fully recyclable, so they also won’t do any harm to humans or the environment at the end of their lifespan.

7. It is too expensive to switch to LEDs

A common LED lighting myth is that LEDs are a lot more expensive than other lights and therefore it is too expensive to fully switch to LED grow lights. This misconception is partly true, but it also doesn’t provide you with the full story. Yes, LEDs are more expensive upfront than, say, fluorescent grow lights, but their costs, in the long run, are actually much less than those of any other bulb type. The rated lifespan of an LED bulb is 50,000 hours which equals 10+ years of average use; whereas fluorescent lights only last for 20,000 hours. In addition, the electricity savings from LED grow lights will quickly pay off the higher upfront price of the lights. You’ll be paying a lot less for electricity without sacrificing quality and yields.

8. LED lighting can’t be dimmed

The last misconception is that LED lights can’t be dimmed, because no matter what dimming technology you use, the bulbs will stay as bright as before. Although some LED fixtures are not designed to be dimmed, some LED lights nowadays are dimmable, allowing you to adjust the brightness of the LED grow light to give your plants the right amount of light.

Conclusion

Now that you know some facts about LED lighting and have read the explanations as to why these LED myths are just that — myths, we encourage you to try growing with LEDs. You will see how beneficial it is to make the switch to LEDs; not only for the energy and money savings but also to increase your plant quality.