Are LED Grow Lights Dangerous For Humans?
Have you ever seen what eyes look like after they've been ravaged by LED grow lights?
Yeah, me neither.
But that doesn't stop some from warning us all of the dangers and insisting we all need protective glasses.
Are they just being overly cautious?
Are they just trying to sell us protective eyewear?
Both are often true, but there is also some truth to the idea that LED plant lights can damage your eyesight.
With that, let's answer the question that brought you here.
Does LED grow lights harm your vision?
Yes, LED grow lights can damage your eyes.
Whether this is something you need to be concerned about depends on the type of light, the intensity, and the duration of exposure.
More details are below.
What Types Of Light Can Cause Us Harm?
Any type of light can be harmful to our eyesight if it is powerful enough. If you’ve ever looked directly at a powerful light source, you’ll know this (and hopefully have looked away quickly enough before any serious harm was done).
However, some types of light are much more harmful than others and even small amounts of certain light can damage our eyes.
Before we discuss those types of light, let’s take a look at the complete electromagnetic spectrum.
As you can see, the range of light that is visible to the human eye occupies a narrow band that is sandwiched between UV light on the right (shorter wavelengths) and infrared light on the left (longer wavelengths).
To simplify things a bit: the shorter the wavelength, the greater the harm to us.
Thus, the wavelengths of light we need to worry about most are blue light and UV light, with the latter being more dangerous than the former.
UV light is further broken down into UV-A, UV-B, and UV-C. UVA is the closest to visible light, which means it has the longest wavelength and is also the least harmful. UVC is the most harmful.
Light from the sun contains all three, but our atmosphere filters out most of the UV-C light. UV-A and UV-B get through the atmosphere and cause us harm. They are the reason we need to wear sunscreen and UV-blocking sunglasses.
When it comes to artificial grow lights, they all contain varying degrees of blue and UV light. Reddish grow lights, like HPS, only contains small amounts. Bluer lights, like Metal Halide or fluorescent, contain much more.
LED grow lights are a little more complicated.
Are LED Grow Lights Harmful To Humans?
LED plant lights with a lot of blue and UV diodes can be harmful. The same goes for all-white lights that emit a cooler white light (5000 Kelvin and higher).
The type and amount of harm an LED light can cause depends on the color and the intensity. Any powerful light can hurt our eyes if we stare directly at it, but that is an easy enough thing to avoid. Just don't stare into your lights.
Apart from that, let's look at the actual effects of blue and UV light, the two wavelengths that are harmful to humans.
Effect Of Blue Light On Humans
The most commonly known negative effect of blue light is what it does to our sleep.
During the day, blue light keeps us alert and awake. But exposure to blue light at night suppresses the secretion of melatonin, which is a hormone that influences circadian rhythms. This makes it harder for us to fall asleep and leaves us more tired and sluggish.
There is also a possibility that lower melatonin levels are linked to obesity, diabetes, and some types of cancer, but much more study is needed to determine if there is, in fact, a connection.
Effect Of Blue Light On Our Eyes
blue light effect on eyes
Blue light can also negatively impact our vision. Our cornea does not do a good job of blocking blue light, meaning almost all of the blue light that hits our eyes penetrates all the way through to the retina.
Too much blue light has been proven to damage light-sensitive cells on the retina. This brings about changes that are similar to macular degeneration, which can result in permanent vision loss.
This is obviously an extreme case and would require a lot of blue light exposure, but we get much more of it these days than ever before, thanks to our various screens (computer, phone, TV, etc.). Adding in high amounts of blue light from your grow room is a definite cause for concern.
The research so far is limited and we lack a good understanding of the long-term effects of too much blue light, and even how much blue light is too much. Nevertheless, it makes sense to err on the side of caution and take steps to protect our eyes.
Effect Of UV Light On Humans
UV light affecting the eyes
Many of the effects of UV light are well known. It causes varying degrees of skin damage, from premature aging to sunburn, to cancer. It also causes damage to our vision and that is what is most concerning to us here.
Effect Of UV Lights On Our Eyes
All three types of ultraviolet light can damage our eyesight, but UVC does by far the most damage. Luckily, our atmosphere blocks out most of it, and it is generally not emitted by most grow lights. Those that do contain UVC light, only emit very small amounts.
UVB and UVA are much more problematic. They affect our eyes in very different, but equally dangerous, ways. UVA light passes through our cornea and hits the retina, just like blue light. UVB light is completely filtered out by the cornea and thus can not reach the retina.
Because UV-A light passes through the cornea, it has been linked to conditions resulting from damage to the retina, like certain types of cataracts. It may also play a role in the development of macular degeneration.
Since UV-B light does not hit the retina, it does not cause those same issues. Instead, it may help cause pingueculae and pterygia, which are growths on the eye's surface. It can also cause painful inflammation of the cornea called photokeratitis, which can cause temporary vision loss in extreme cases.
What does this all mean for us?
Well, now that we know how the different types of light affect us, we can better discuss what kind of damage LED lights might be causing. They are not generally strong enough to cause skin damage, so most of the potential damage is to our eyes.
Effect Of LED Lights On Eyes
led diodes bad for eyes
Most LED fixtures contain varying degrees of blue light and UV-A diodes. Some also contain UV-B diodes (very rare) or supplemental UV-B bulbs. These lights may also emit some UV-C light.
We now know that both UV-A and UV-B light can damage our eyes and that blue light can result in negative effects as well. Whether we need to worry depends on the level of exposure.
Do You Need Glasses For LED Grow Lights?
If you just have a small light fixture and/or you don't spend much time beneath the lights, you don't have to worry. The UV levels are not high enough to cause damage with such minimal exposure.
However, if you have powerful lights and you spend a lot of time working beneath them, I highly recommend you get some form of eye protection.
LED Grow Light Eye Protection
Glasses protect from too much light
You have several options.
Most people will recommend against regular sunglasses. That is not because they don't protect the eyes. Rather, it is because they are not designed for the unique light emitted from a grow light.
This means that your plants will not look natural if you use regular sunglasses.
Grow glasses that are tuned to a specific spectrum will result in your plants looking completely natural when viewed through the glasses. This makes it much easier to inspect your plants and detect any discoloration or other signs of problems.
The main issue here is that you need glasses that are made for the exact spectrum of your lights. General LED glasses will work for most of the lights that have a mix of primarily red and blue diodes, but they will not be perfect, since all of those lights have a slightly different spectrum.
If you have an all-white LED, then you'd actually be better off with HPS or MH glasses, depending on the color temperature of your light (MH glasses for cooler lights and HPS glasses for warmer lights).
If you don't care too much about the plants looking unnatural (i.e. pink/purple), then you can use a pair of regular sunglasses.
Just make sure they protect from UV rays. Many do not protect from UVC, so make sure yours do, if you have a light that emits UVC rays.
Other Common Questions
Here are the answers to a few more common questions we get regarding grow lights and their impact on our health.
Are HPS Lights Bad For Your Eyes?
As mentioned above, high-pressure sodium lights contain a lot of red light, a small amount of blue light, and very little UV light. For that reason, they are safer for your eyes than most other types of grow lights.
That said, HPS bulbs are very powerful and can cause damage merely through their intensity. You definitely want to avoid staring directly into the lights.
Can Grow Lights Cause Cancer?
As mentioned above, there is some concern that prolonged blue light exposure could cause cancer, but this has not been studied, so nothing is known for sure. The same goes for UV light.
What IS known is that UV light can cause skin cancer. This is not something you have to worry about with grow lights, since they do not contain high enough levels of UV light. Just don't lie directly beneath a powerful grow light naked for hours at a time and you'll be fine.
Actually, maybe don't lie under one naked for any amount of time. That's just weird.
Are Grow Lights Safe For Humans?
Yes, as long as proper precautions are taken, grow lights are safe for humans.