Skip to Content

Do Plants Need UV Light?

Do Plants Need UV Light?When you’re striving for the perfect environment for growing plants, one of the top concerns is UV (ultraviolet) light. UV light occurs naturally in the sun’s light so all plants that grow outside already experience its benefits. The question is whether plants that grow indoors need UV light, and the answer isn’t as simple as yes or no. It’s a more complicated issue that requires a little more in-depth knowledge. We’ve done the research, broken it down for you, and made it really easy to understand so you know if you should be using UV light to help nurture and grow your plants.

The most important thing to know about UV light is that there are three different kinds and only two are proven effective to use when growing plants.

  • UV-A and UV-B are both good for plants. The benefits of both kinds of ultraviolet light exposure include deeper and richer plant color, increased nutrient content of fruits and vegetables, and a stronger defense against harmful fungus. UV-A is okay in any quantity, but too much UV-B can damage a plant’s DNA.
  • UV-C is extremely harmful to plants and even a small amount of exposure to it can permanently damage a plant’s DNA.

Do plants absolutely have to have UV light to grow? No. However, the benefits of the right kind of exposure to good UV light are so significant that you’ll want to give serious consideration to using it on your plants. Keep reading for more information to help you make this important decision.

How to use UV Light

There are several different types of UV light. Some are great for plants, and some may be harmful.

Avoid UV-C light at all costs

There are no benefits at all to exposing a plant to UV-C light. UV-C is completely absorbed into the atmosphere prior to reaching earth, so therefore it isn’t naturally present on our planet. Even the smallest amount of exposure to it will irreparably damage your plant’s DNA.

UV-B is beneficial, but be careful

In addition to the benefits we listed above, UV-B light can also change the DNA of fungi that attack and damage or kill plants. When its DNA is altered, that prevents the fungus from spreading and hurting the plants. However, prolonged exposure to UV-B light can also alter the DNA of the plants, which is obviously problematic. Check instructions on your grow light’s box to make sure you don’t keep the light on too long. UV-B light is less than 2% of the UV light that gets to the earth’s surface.

UV-A exposure is great for plants with no side effects

When added during the growth cycle for plants, UV-A light can produce stronger, more plentiful plants that are able to withstand fungus and other attacks. It can also help fruits and vegetables look and taste better. UV-A light accounts for more than 98% of the UV light that reaches earth. 

Plants are Naturally Protected

Plants have trichomes covering their surfaces. Trichomes look like teeny tiny hairs on the plant, and they serve to reflect bad UV away from the plant. Additionally, when they are exposed to UV-A and UV-B lights, plants release a chemical called glycosides, which can entice humans by helping the plant to produce a prettier and better-tasting fruit or vegetable. At the same time, glycosides deter insects from eating the plants.

Exposure to the right UV lights can lead to taller plants

UV-A and UV-B can help a plant develop photomorphogenic tendencies. Plants that grow toward the light are photomorphogenic. When this happens, they tend to grow taller and stronger than plants without photomorphogenic tendencies.

Potential Side Effects of Human Exposure 

Humans exposed to UV light can have problems as well. Exposure to UV light can cause a multitude of problems, including skin cancers. Most good quality sunscreens will protect against the skin damage caused by UV light, so please make sure that you give your skin a good coating before spending a lot of time with your plants under the UV lights.

Differences in UV Grow Lights for Plants

A quick online search will reveal that there are hundreds if not thousands of choices when it comes to these types of lights. It can be overwhelming, and you want to choose the right UV light that will help your plants the most. Things to consider include the size of the space where you’re growing your plants, whether the light is full spectrum (meaning UV is part of the light waves it emits), and the durability of the product. Now is not the time to skimp; make sure you spend the money you need to get the right light for your plants. Their health may depend on it! Check out this product by Amazon.com.

The Difference Between UV and Infrared Light 

Although they both have benefits to plants, they’re not the same thing. They have different frequencies on the spectrum of light. UV radiation is harmful to skin, while infrared is not. Infrared light is used safely and effectively in a variety of medical procedures to check for things inside the human body. Too much exposure to UV light can cause cancer, but interestingly, UV light has also been used to zap cancerous tumors. UV light is used by police and detectives to check surfaces for residues that might indicate a crime has taken place, while law enforcement uses infrared technology to help them see better in dark spaces. 

Can you use a reptile light instead of a grow light?

The short answer is yes. Most reptile lights emit UV-B, which is what the plants need. However, in the long term, you should really consider spending the money to buy a separate, full-spectrum light. Those are specifically designed to meet the light needs of your plants and will be most beneficial to their growth in the long term.

Have Fun With Your Plants

The science beyond the use of UV light is really important to the life of your indoor plants. But always remember that you’ve bought these plants to enjoy them and so that they can bring color and life to your living space - and maybe even some fruits or vegetables. So have fun with the plants that you choose, and enjoy creating the perfect space for them to grow and flourish!

Monte Drake Jr.

Tuesday 10th of March 2020

UV-C in small doses can be used as an anti-bacterial and kill off funguses and bacterias. Please inform yourself fully before making conclusions.