Full Spectrum LED Grow Lights: The Truth You Need to Know
Many LED lighting suppliers will say that full-spectrum LED grow lights are the best option for growing plants because they mimic the natural light from the sun. The argument goes:
“Plants have grown under sunlight for millions of years. Why would we want to change what mother nature knows is best?”
Well, LumiGrow wants to let you know that there is no such thing as a full-spectrum LED grow light.
A full-spectrum LED grow light is simply a marketing term that implies that your grow light closely resembles light from the sun. This marketing term comes from the concept of “full-spectrum light,” which in recent years has been used to refer to electromagnetic radiation from the UV to infrared wavebands.
The full-spectrum LED grow light is the newest evolution of an already confusing term. Originally, full-spectrum light described the only real full-spectrum light source, the sun.
Over time, the term began to take on other characteristics of sunlight. The commercial lighting industry began using the name “full-spectrum” to sell lights that produced a Color Rendering Index (CRI) over 90. Humans perceive colors more accurately under light sources with a CRI over 90, much like how we see colors in our natural world under daylight. This was a beneficial feature for human environments such as offices, outdoor spaces, and others.
With the advent of horticultural lighting, companies once again began to borrow the term. Only this time, they claimed that full-spectrum LEDs could reproduce the effects of sunlight for plants.
Thus, the full-spectrum LED grow light was born. Unfortunately, lighting for plants is not quite that simple.
Problems with Full-Spectrum LED Grow Lights
There are many issues with the concept of full-spectrum LED grow lights. For starters, just because you name something, doesn’t make it true. This rhetoric may have made sense for lighting designers interested in selling lights so humans could see, but plants require light to feed, grow, and live.
There are three major problems when talking about full-spectrum grow lights:
- Full-Spectrum Grow Lights Aren’t Optimized for Plants
- Full-Spectrum Grow Lights Don’t Include the Full Solar Spectrum
- Full-Spectrum Grow Lights Are Not Dynamic Like the Sun
1. Full-Spectrum Grow Lights Aren’t Optimized for Plants
A major problem with many full spectrum LED grow lights is that they are designed to give the appearance of daylight without being custom-tailored for rigorous plant growth.
When you hear that the diodes in your full spectrum grow light are 3,000k to 4,500k, or 5,000k+, this degree of Kelvin (K) refers to how “cool” or “warm” your light is in appearance.
Our goal as growers is to improve the lighting characteristics most important for plant growth. This means not only getting enough PAR light, but also the right mix of light spectra, which brings us to problem #2.
2. Full Spectrum Grow Lights Don’t Include the Full Solar Spectrum
Sunlight itself is complex, and many scientists are still working to understand it today. You can see that sunlight also contains ultraviolet (UV) and infrared light (as well as x-rays, radio waves, and others, but we’ll leave those alone for now).
Although PAR is the most important light for photosynthesis, plants still respond to radiation outside of the PAR spectrum. For instance, UV light elicits protective compounds in plants similar to the way humans become tanned in the presence of UV.
Plants also use a type of infrared light called “far-red light” to induce a shade avoidance response, causing them to stretch and can induce early flowering.
To create a light source that elicits plant response the same way the sun does(grow light with UV) would be too costly and downright impossible given current grow light technology. Nor would you want to create such a grow light, which takes us to problem #3.
3. Full-Spectrum Grow Lights Are Not Dynamic Like the Sun
Not only would it be too costly to create an actual full spectrum LED grow light, but if such a thing even existed, its performance would still not accurately reflect what’s happening in nature.
The sun’s spectrum is in constant flux due to changes in weather or its position in the sky relative to earth.
Because of this phenomenon, it’s best to think about the interaction between sunlight and plants as a continually changing process.
If you hang your full spectrum grow lights in a greenhouse, you will still reap the benefits (and disadvantages) of this natural process from the sun. But if you take those same full-spectrum lights and hang them indoors, they will not behave like the sun.
Photomorphogenic responses by plants are co-regulated, which means that certain expressions of the plant may turn on or off based on the amount of light within one waveband relative to another.
Full Spectrum LED Grow Lights: Summary of Recommendations
Viparspectra P1500
VIPARSPECTRA Pro Series P1500 LED grow light has adopted the NEWEST SMD LED Technology to increase efficiency and lifespan while improving light penetration. An added dimmer knob is featured to manipulate the brightness level of the entire light from 5%-100%, allowing flexibility to obtain perfect growth performance. This light can replace a 400W HPS/MH lamp while consuming only 150W.
The spectrum consists of 660nm red light, and 3500K & 6500K white light. The P1500 provides exceptional full-spectrum lighting, fully capable of all plant stages. This light also adopts a reliable UL listed waterproof driver. Achieve greater yield with the P1500!
The Dimmable P1500 LED grow light is perfect for 3’x3’ vegetative coverage at 20” and 2.5’x2.5’ flowering coverage at 16”. Remember to properly adjust the height and brightness accordingly to your plant's desired level for optimal growth.
Mars Hydro FC 3000
Mars Hydro New Arrivals - FC 3000 LED Grow Light with LM301B Osram Diodes. This Mars Hydro FC 3000 fixture is ideal for a seedling to harvest grow in a grow tent or in a grow room. Use as primary lighting.
Ultraviolet and infrared light bulbs are incorporated alongside the Epistar SMD chips to create the full spectrum sunlight-like light output. The no-fan design keeps the SP 250 cool while conserving energy. The quantum light board is covered by glue for water resistance. Adjustable Meanwell driver. No veg or bloom switch, the sunlight spectrum is suitable for growing cannabis from seed until harvest.
Conclusion
These modern LED grow lights allow for precision control of your plants. By adjusting your grow light spectrum wirelessly, it’s possible to speed up flowering times, improve your plant’s biochemistry, or customize your plants’ structure to root better and be more easily managed.