What is the best UV light for plants? 2020 Updated

After a recent conversation with a customer about the risk of best UV light for plants in the grow room, we became intrigued about the full spectrum of UV light. Do plants need UV light to thrive? Is exposure to UV lights harmful? And crucially for us at Happy Hydro, can you protect your eyes from UV rays in the grow room?

What we quickly discovered in our research was that the available information sprawling across the internet is that many sources aren’t as clear-cut as we had hoped.

It took us a while to get the information we needed, from a variety of sources. Its why we’ve put together the following guide, the truth about UV lights for you and your plants.  

With the explosion occurring in indoor and urban farming, there has been an increasing desire to continue to refine the growing process in a cost-effective manner that will still yield positive results for the targeted plants. Much of the existing research on the use of LEDs in agriculture has focused on the wavelengths of visible light and the spectrum that plants need for various processes. During extensive research, “NASA determined that LED lights are the best single source lights for growing plants on Earth as well as in space [6].” In fact, there have been many studies conducted to identify the relationship between various wavelengths and their impact on plant growth. This information will allow for the further development of customized spectrum lighting that produces greater results for the plant at lower energy costs. For example, the red-light spectrum (630-660 nm) has been determined to be essential for stem growth and expansion of leaves. It is also the wavelength that regulates flowering and dormancy periods.

While early LEDs left most plants (and growers) wanting more, the latest state-of-the-art LEDs provide more viable options for indoor growing that will yield substantial cost savings (if paired with the right lens material), especially compared to traditional lighting options such as High Pressure Sodium (HPS).

Now, further advancements in UV LEDs are making it possible to bring the additional benefits of ultraviolet light, particularly UV-A and UV-B, to the indoor grow process in a very targeted way. Researchers found that in the absence of UV light, certain plant breeds may “develop callus-like intumescence growth on leaves and shoot tissues [7].” Ordinary glass, for example, blocks over 90% of UV-B radiation [8], therefore, plants grown in greenhouses or other similar environments, without supplemental lighting may experience adverse effects.

UV light has also been shown to drive increases in the plant production of active substances in medicinal plants, including antioxidant benefits of numerous plants or THC levels in cannabis. Plants have chemical processes which enable them to identify the different wavelengths of light that trigger certain responses, including reactions to UV light that can alter plant shape and change chemical make-up [9]. This area of photonics, however, still needs a lot more research focus to truly understand all of the impacts, including the best methods for deployment.

UV light can speed up the germination process for starting seeds when grown indoors. As growers transplant seedlings to more intense light sources, UV strengthens the plants, better preparing them for high intensity light. Transplanting seedlings from low intensity lighting to high intensity lighting can shock or slow the plant’s growth. This is especially true when moving young plants from indoor to outdoor. Exposure to UV in the early stages of plant growth reduces shock time and speeds up the production process.

Further research is being done on the effects of UV on different strains, cannabinoids and other elements of cannabis.

ECO Farm 30W LG UV395nm Supplemental Lighting Quantum Board

• GIVE YOUR PLANTS THE BEST - The next best thing to sunlight, our indoor plant mini grow lights are perfect during the long winter months, when your growing room does not get enough natural lighting. It is also viable for starting vegetable seeds indoors, before bringing them outside to your garden.


• UPGRADED AUTOMATIC TIMER - The improved two-way memory system now allows the LED grow lamp to turn on at the preset time automatically. If you set the 12H timer function at 8AM, it will turn off at 8PM, and turn back on at 8AM the next day, everyday.


• FULL SPECTRUM BULBS - 26 Red and 14 Blue LED chips emitting across two lighting strips with minimal heat, powerful enough for the plants to grow and thrive. Turn your house plants into green and succulent ones with these LED grow light fixtures and bulbs.


• GROW ANYTHING - Grow kitchen herb, fruits and vegetables like tomato, english cucumber, leek, microgreen, watermelon and more. Flowering plants like orchid and wisteria. The plant light is great for any plant types and guarantees growth and yields wonderful results!


• STURDY & FLEXIBLE – The gooseneck arms can be adjusted up to 360 degrees so you can position the light in any direction. This maximizes coverage for your seedlings, and looks after your potted plants, succulent plants or hanging ones. Make use of the mounting clip to clamp onto desktop or anything sturdy.

ECO Farm Supplemental Grow Light deserves for your try！

Gavita 30W UV LED Grow Light

• Portable Design: Lightweight (Compact size: L10.23*W2.64*H1.85inches Weight: 185g),portable hand-held design with battery inbuilt can sterilize the required area at any time.. It can easily be stored in a hand bag, back pack or luggage. Disinfect whenever and wherever needed even while you are on the go! The ultraviolet light sanitizer is rechargable, which can work 2 hours after charging fully.This uv light sterilizer is rather convenient


• Safety Design: With built-in smart sensor, this uv light sterilizer can shut down automatically when it works 3 minutes.The uv lamps has child lock button,if we lock this button, it won’t work.This function can prevent children from turning on it.This uv disinfection lamp is safe to operate for us


• Warning Tip: Ultraviolet rays can burn eyes and skin. Do not point at people or animals during use to ensure safety!Pls keep the uv lights for disinfection away from children

Yes, UV has benefits for plant growth, but it can still cause damage to plants and humans if not used properly.

Do not expect to enhance your plant growth by going out and purchasing a sun tanning lamp. Sun tanning lamps provide a lot of UV and human skin can only be exposed to them for short periods of time. Exposing plants to that much UV can quickly kill them.

Growers should provide their plants with a full quality spectrum which emits the right amount of UV. That full spectrum light should mimic natural sunlight to make the plants feel as if they are being grown outdoors.

Natural sunlight isn’t really an option for indoor gardens. That’s why grow lights are key for people trying to grow their own plants indoors. While many indoor grow light options produce little to no UV light, many HORTILUX grow lamps are designed with an exclusive light spectrum to give your plants the UV rays they need to thrive.

The amount of UV light being produced by your grow light is just another factor in deciding what is the right light for your grow.

What is the best UV spectrum for growing cannabis? When it comes to the full UV light spectrum, its best to stick with UV-A and UV-B varieties for your plants. As mentioned, there is no benefit of direct UV-C exposure to yourself or to your crop (although UV-C may help sterilize your grow room). If you are considering using the UV-C technique to disinfect your workspace, consider safer organic alternatives to pest control, including as integrated pest management (IPM) techniques.

Depending on the species of plant you intend to grow, there will also be a precise formula for just how much UV light you’ll need, and when you should introduce it. In some cases, UV light over prolonged periods has stunted growth. In other cases, it can enhance valuable characteristics of your crop. For example, for growing cannabis, you’ll only want to introduce UV light during the final few weeks of flower, to boost trichome development, but constant UV lighting for leafy greens tends to stunt their development.