Are White LED Grow Lights Good for Growing?
For people who love to grow indoor plants, there are always continuous debates on the best grow light that gets the best results for growth. One of the most recent debates is the effect of white LED lights on indoor plant growth.
A study at Chiba University measured the effects of supplemental lighting with LEDs on tomato yield, which included white LEDs.¹
Based on the unit photons emitted, the white LEDs showed as high efficiency as the red LEDs in increasing tomato yield, followed by the blue ones.
This is quite an interesting result because not many grow lights include white spectrum, although some of the higher end models have started to include it.
The study found that tomato yields increased 12 to 16% when white LED lights were included with a mix of red and blue lights to grow tomatoes.
Even though the red and blue lights contributed to the result, the study’s authors concluded that “The results were probably due to the white LEDs that contained more than 50% of green light characterized by high penetration into the canopy.”
A second study observed lettuce grown using only red blue spectrum compared to lettuce grown using red blue plus white spectrum.² The study found soluble sugar and nitrate contents in the lettuce grown with added white spectrum was significantly higher and lower, respectively. If you’re wondering -- that’s exactly the result you’d want.
Researchers also observed higher shoot and root fresh and dry weights as well as higher crispness, sweetness, and better plant shape for the lettuce grown using white light.
What is White Light, Specifically?
While most indoor growers are familiar with the benefits of using purple growing lights, white LED lights are a newer consideration.
Almost all growers have previously considered white light to have little or no value for plant growth. However, this is not actually true with white LED Lights, as seen in the studies cited earlier.
The white light spectrum includes a few colors currently included in all LED grow lights, like blue and red. But it also comprises of a few wavelengths not included in significant intensity in most LED grow lights today.
The full white light spectrum can be seen in the table below:
Most LED grow light spectrum charts will already show these wavelengths, but the intensity of the wavelengths other than red & blue is weak. Below we linked to a brand of more modern grow lights that includes a full white spectrum, including the all important red and blue as well.
White LED lights are also great lighting to help enjoy the plants as they grow, and they provide a 40% light absorption rate. Additionally, because they are LED, these lights will not burn or over chafe the leaves, ground or soil with a drying light.
What Color LED Is Best For Plants?
While there are a host of different grow lights produced, there has not been enough discussion of the benefits of using white LED grow lights for plants.
With that said, the studies cited above prove that white spectrum LEDs are best for plants.
Traditional high intensity bulb lamps are not as effective because they use more energy and the light released is lower quality.
The use of high intensity bulbs for growing can create a hot environment that’s hard to control. This has often been a significant complaint for indoor plant growers.
Because of this, an increase in plant light analysis was done that included the use of white LED lights. Part of the desire to compare white LED lighting for plant growth came from their low energy use and ability to stay in use for longer periods of time safely.
Based on the studies above, we conclude that more high quality grow lights should include white spectrum. In fact, many are starting to do so.
Which Grow Lights Utilize White LEDs?
The Mars Hydro TSW 2000 is a modern, low price range quantum board grow light that has an intense white light spectrum. This light is the best value on the market right now. You can click the image below for more details.
Mars Hydro TSW 2000:
The HLG 300 V2 R-Spectrum Quantum Board Grow Light is a great modern white spectrum grow light at a mid-price range cost.
It emits a full white light spectrum (including blue & red) . It’s the most modern LED grow light currently on the market, and will cover a 3’x3′ space with ease. You can click the picture below for more details.
HLG 300 v2:
Still looking for more white spectrum LED grow light options? You can also check out my review on the best COB LED grow lights which also include full spectrum white LED light integrated into the LED chips.
What Are The Best LED Grow Lights For Small Plants?
The white spectrum LED grow lights above are meant for fruit, vegetables, or cannabis. They cover a 3x3 foot area, and may be overkill for smaller plants such as flowers or succulents growing in a small 1x1 foot area.
If you’re looking for a small white spectrum LED bulb that’ll cover a 1x1 foot area and is sufficient for smaller plants like succulents, flowers or seedlings, I highly recommend the Sansi 40w daylight LED bulb. I have these bulbs at home and wrote an article about my experience with them here. You can click the image below for more details.
White, Red and Blue Wavelengths -- Not White Alone:
Since most white LED lights run at a lower light absorption rate, and are not comparable to natural sunlight, the use of red, purple, blue or green LED lights are often used in combination with white lights.
When red and white, purple and white, blue and white or green and white LED lights are used in combination, the outcome of light absorption is much better.
Using white LED lights with other primary color LED lights offer the added benefits of visibility and better room atmosphere. This allows plant growth to occur in any room of a home versus a specified plant room.
In some cases, people have used a combination of red, white and blue LED lights to give the plants their much-needed light combinations while enriching the room with a patriotic glow.
When it comes to indoor plant growing, studies have shown the use of LED lights has been found superior to traditional plant growing lights. Using LED lights significantly reduces energy consumption and does not create overheating or the hazards of higher heat risks from ongoing daily usage.
Are White LED lights good for growing cannabis or other plants? The answer is yes. They play an important role in being one part of the absorbable spectrum, but it’s not enough to fully nurture your plants on its own unless it’s mixed with red and blue spectrum as well.
This is why white spectrum LED grow lights are always mixed in along with other colors. In addition, you still need white LED grow lights as part of a safe grow space. You’ll need them to keep your room safely lit while you let your colored grow lights rest.
Fortunately, you won’t need nearly as many white LED lights for your room. You also won’t need such high intensity ones compared to your cannabis grow lights.
Yes, white light spectrum is currently the best spectrum for plants.
Yes, white light spectrum is currently the best spectrum for cannabis.
Purple grow lights are still useful for growing plants, but about 10-15% less efficient according to some studies.
1. MARUO, Toru, et al. “Effects of Supplemental Lighting with Light-Emitting Diodes (LEDs) on Tomato Yield and Quality of Single-Truss Tomato Plants Grown at High Planting Density.” Environmental Control in Biology, Japanese Society of Agricultural, Biological and Environmental Engineers and Scientists, 11 June 2012, https://www.jstage.jst.go.jp/article/ecb/50/1/50_63/_article.
2. Lin, K., Huang, M., Huang, W., Hsu, M., Yang, Z. and Yang, C. (2013). The effects of red, blue, and white light-emitting diodes on the growth, development, and edible quality of hydroponically grown lettuce (Lactuca sativa L. var. capitata). Scientia Horticulturae, 150, pp.86-91.
4. Chandra, Suman, Hemant Lata, Ikhlas Khan, and Mahmoud Elsohly. “Photosynthetic response of Cannabis sativa L. to variations in photosynthetic photon flux densities, temperature and CO2 conditions.” Physiology and Molecular Biology of Plants 14.4 (2009): 299-306.
5. Eichhorn Bilodeau, Samuel et al. “An Update On Plant Photobiology And Implications For Cannabis Production”. Frontiers In Plant Science, vol 10, 2019. Frontiers Media SA, doi:10.3389/fpls.2019.00296. Accessed 14 Oct 2019.