Do Led Grow Lights Emit UV? | Is it Safe for People and Plants?

by Morgan

May 12, 2022

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Do Led Grow Lights Emit UV? Almost every plant grower asks the question when they want to install one. It's a tricky question because several factors play into the answer. First, you'll need to look at what grow lights you'll be using and how many watts of wattage they're running. The only way to know for sure is to look at them both physically.

As we all understand, growers require uninterrupted light. We also know that LED lights are the best choice to use as you want to get good yields with minimum effort. But how much light will LEDs produce, and what type of spectrum will these new LEDs grow lights emit?  

The wattage is the most crucial factor in deciding if your grow lights emit UV. A LED light with a high wattage will produce more heat and, therefore, more UV radiation. But don't worry, the amount of UV radiation emitted by these lights is still within the safe range for humans and plants.

Purple lights with weed plants

What Exactly Is UV?

Ultraviolet light is made up of a wavelength that ranges from 10 to 400 nm. It's relatively shorter than other visible lights but much longer than the X-rays. Sunlight is made up of UV radiation, which accounts for at least 10% of the sun's entire electromagnetic output. The electric arcs and other specialty lights can then produce it.

On the other hand, the long-wavelength UV-C cannot permeate the atmosphere because the ozone layer absorbs it. UV-B and UV-A short-wavelength UV light can reach the earth's surface, which is essential for plant development and animal survival.

So, there you have it, grow lights emit UV rays but only a tiny amount. You can rest assured that your plants and yourself will be perfectly safe under these lights.

The ultraviolet light range of the electromagnetic spectrum is a comprehensive portion split into three parts; UV-A, UV-B, and UV-C. Each one of these has a different effect on organic matter.

  • UV-A rays consist of 95% of UVA light that reaches the earth's atmosphere. They are present during all daylight hours, even when the sun is behind clouds. These rays are not very harmful to humans because they do not penetrate deep into the skin. However, they can still cause some damage to the skin over time and lead to premature aging and wrinkles.
  • UV-B rays consist of at least 5% of the UVB light that reaches earth. They are strongest during the midday hours (10 am-4 pm) and are more harmful than UV-A rays because they penetrate deeper into the skin. These rays can cause sunburn, skin cancer, and other damage to the skin.
  • UV-C rays make up a minimal amount of the UV lights that touch the earth's surface. They are entirely absorbed by the atmosphere and do not reach the ground. However, they can be found in artificial lightings, such as mercury vapor lamps. These rays are extremely harmful to humans and can cause severe burns and eye damage.

Now that you know more about UV light, you can see why it is essential to use grow lights that emit this type of radiation. UV light is necessary for weed plant growth and development, and without it, the cannabis plants would not be able to photosynthesize and produce the food they need to survive.

Types of LED Lights That Emit UV Light

There are a few different types of LED lights that emit UV light. These include:

  • UV LEDs: These LEDs emit a minimal amount of UV light. They are usually used with other grow lights to provide plants with a full light spectrum.

  • Blacklight LEDs: These LEDs emit a moderate amount of UV light. You can use these lights independently or in conjunction with other grow lights.

  • Full Spectrum LEDs: These LEDs emit a wide range of wavelengths, including UV light. One can also use these LED lights independently or with other grow lights.

The Importance of UV Lighting for Plants?

Vitamin D production in the human body is also triggered by ultraviolet radiation. Vitamin D is necessary for strong bones and teeth and the body's calcium absorption.

In plants, UV light helps to trigger the production of chlorophyll. Chlorophyll is a green pigment that gives plants their color and allows them to absorb sunlight. This pigment is essential for photosynthesis, which is how plants turn sunlight into food.

UV light also helps to protect plants from pests and diseases. The UV rays kill bacteria and fungi that can harm plants and help repel insects.

What Amount of UV Exposure Is Good for Plants?

As with humans, too much UV exposure can be harmful to plants. Plants exposed to UV radiation will develop bleached leaves and stems, stunting their growth.

On the other hand, inadequate UV exposure can also harm plants. If plants do not get enough UV light, they will not produce enough chlorophyll and will not be able to photosynthesize properly. It can lead to slow growth and poor health.

So, how do you know if your plants are getting the right amount of UV light? The best way to tell is by observing them closely. If they grow well and have green, healthy leaves, they are probably getting the right amount of UV light. If their leaves are yellow or bleached, they get too much UV light.

Purple led lights with a weed plant in the corner


Using artificial grow lights, you can adjust the amount of UV light your plants get by moving the lights closer or further away from the plants. You should also experiment with different light bulbs to find the one that emits the right amount of UV for your plants. The LED lights produce the full spectrum of light, including UV light.

When using LED grow lights, you can position the lights close to the plants without worrying about them getting too much UV radiation. Because these lights don't emit too much heat, they won't harm your plants' leaves or stems.

How Do I Know When My Plant Needs More or Less Grow Light?

The best way to know when your plant needs more or less grow light is by observing it closely. If the leaves are yellow or bleached, they get too much UV light. If the plant is not growing well or its leaves are pale, it is not getting enough UV light.

You can also use a grow light meter to measure the amount of UV light your plants receive. These meters are relatively inexpensive and can be found online or at your local gardening store.

A grow light meter will help you ensure that your plants get the required amount of UV. It is crucial to remember that the amount of UV light that plants need varies depending on the type of plant. For example, desert plants need more UV light than tropical plants.

If you are not sure how much UV light your plants need, it is best to start with a low amount and increase it gradually until you find the sweet spot.

Woman hands with weed plant


Do LED Grow Lights Produce the Spectrum Needed for Plant Development?

Yes. LED grow lights can provide the entire light spectrum, including UV light. Because LED lights don't produce much heat like the typical grow lights, they won't harm your plants' leaves or stems.

When using LED grow lights, you may place them close to the plants without worrying about them being exposed to too much UV radiation. LED lights don't produce much heat like the other grow lights, so they won't harm your plants' leaves or stems.

Advantages Of LED Grow Lights?

The following are some of the advantages of using LED grow lights: -

  1. They are more energy-efficient than other grow lights.
  2. They emit very little heat, so they will not damage the leaves or stems of your plants.
  3. They can be positioned close to the plants without worrying about them getting too much UV radiation.
  4. They come in a variety of colors and intensities to suit your needs
  5. They are relatively inexpensive and last a long time

Drawbacks Of Using LED Grow Lights?

Some drawbacks to using led grow lights include:

  1. They can be blinding if you look directly into them
  2. The light they emit is very intense, so it is essential to position them correctly so that your plants get the right amount of light.
  3. They don't emit too much heat compared to grow lights, so they may not be as effective in colder climates.
  4. They are not as widely available 

How Much UV Do the LED Lights Emit?

The amount of UV that the LEDs emit depends on the bulb type. Some bulbs emit more UV light than others. You can experiment with different bulbs to find the one that has the right amount of UV light for your plants.

You can also use a grow light meter to measure the amount of UV light your plants receive. These meters are relatively inexpensive and can be found online or at your local gardening store.

A grow light meter will help ensure that your plants get the proper UV light. It is important to remember that the amount of UV light that plants need varies depending on the type of plant. For example, desert plants need more UV light than tropical plants.

Tips For Indoor Growers When Using LED Lights

If you choose to use LED lights for your indoor plants growth, there are a few tips to keep in mind:

Have a Better Understanding of Radiations and Spectrums

One essential item for indoor marijuana growers is a better understanding of the spectrum and how different types of light can affect plant growth.

A weed plant


Make Sure Your Plants Get Enough UV Light

Another essential thing to remember is that plants need UV light to grow properly. If your plants are not getting enough UV light, they may become stunted, or their leaves may turn yellow. You can use a grow light meter to measure the amount of UV light your plants receive. 

These meters are relatively inexpensive and can be found online or at your local gardening store.

Experiment with Different Bulbs

As we mentioned before, not all LED bulbs emit the same amount of UV light. You may need to experiment with different bulbs to find the one that emits the right amount of UV light for your plants.

Use a Reflector

If you are using an LED grow light, you may want to use a reflector to increase your plants' amount of light. Reflectors can be found online or at your local gardening store.

plants growing under the purple lights

Be Careful of Heat build-up with LEDs

One thing to be aware of when using LEDs is that they can emit a lot of heat. This heat can build up and damage your plants if you are not careful. It is essential to position your lights correctly and keep an eye on the temperature of your grow room. You may also want to use a fan to help keep the air moving and prevent heat build-up.

Choose the Right LED Grow Lights

Not all LED grow lights are created equal. There are a lot of different factors to consider when choosing the right LED grow light for your plants. Some things to keep in mind include:

  • The type of plants you are growing
  • The size of your grow room
  • The amount of light your plants need
  • The spectrum of light that your plants need
  • The intensity of the light
  • The price

 There are many different LED grow lights today, so it is essential to do your research before buying one. You can read reviews online or talk to other indoor growers to determine which lights they recommend.

Weed plant under led

FAQs

1. Does LED Grow Lights Give Off UV?

LED grow lights give off UV, but not as other types of grow lights. If you are looking for a light that emits a lot of UV light, you may consider using HPS lights. 

2. Do All LED Bulbs Emit UV Light?

No, LED bulbs do not all emit UV light. To find one with the proper quantity of UV light for your plants, one has to try different bulbs.

3. Can LED Grow Lights Be Used for All Types of Plants?

Yes, growers use LED grow lights for all types of plants. However, some plants may need more UV light than others. If you are growing plants that require a lot of UV light, you may consider using HPS grow lights. 

4. Does The UV Emit by LED Affect Our Eyes?

No, the UV emitted by LED does not affect our eyes. However, it is essential to be careful of heat build-up with LEDs. Heat build-up can damage your plants if you are not careful. It is crucial to position your lights correctly and keep an eye on the temperature of your grow room. You may also want to use a fan to help keep the air moving and prevent heat build-up.

Final Thoughts on Using LED Grow Lights

Indoor growers will benefit greatly from LED lights. They emit little heat, so they are perfect for warmer climates. They also emit a lot of light, so they are great for use in smaller grow rooms. If you are looking for a light that emits a lot of UV light, you may consider using HPS grow lights or infrared light.

Whichever type of light you choose, make sure to do your research and choose the best one for your plants. 

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About the author 

Morgan

I discovered the benefits of Cannabis at a young age in 2002, with years of trial and error, my knowledge grew just like my plants. As my love for cannabis unfolded I began to teach and learn, trying to gain as much information and practical growing experience.

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