Full Spectrum Grow Lights: Enhancing Plant Growth and Yield (2024)

Full-Spectrum is a term that has been used in the horticultural lighting industry for years, since the first grow lights entered the market. But what exactly does “full-spectrum” mean?

When Kind LED Grow Lights revolutionized the grow light industry in 2014, we started referring to our lights as Full Spectrum to indicate that the spectrum of our grow lights provide your plants with all of the light they need to grow and thrive from seed to harvest. Since then, practically every LED grow light manufacturer on the planet has started referring to their lights as "full-spectrum," and the phrase has become a source of tremendous confusion for customers and manufacturers alike.

Inthe past few years, the industry has seen a surge in popularity of white-light LED grow lightswhich also claim to be full-spectrum grow lights, however they are using the term "full spectrum" in a different way than Kind used it in 2014.

Full-Spectrum lighting technically means that a light covers all wavelengths of the electromagnetic spectrum that are helpful to plants. However, the term full-spectrum was also used in the 1960s by photobiologist Dr. John Ott to describe electric light sources that simulate the visible and ultraviolet (UV) spectrum of natural light (source), and this seems to be the definition that white-light LED manufacturers refer to when they call their fixtures "full spectrum," as one thingthese fixtures all have in common is that they tend to mimic the look of natural light.

In the interest of clarifying some of these confusion, we have started to refer to our own fixtures as "targeted" full-spectrum grow lights. Let's take a look at the differences between these two types of fixtures.

Full Spectrum Grow Lights

The range of wavelengths which are most helpful to plants falls between 400 and 700 nanometers, and is commonly referred to as PAR, or Photosynthetically Active Radiation. This range of light supports the process of photosynthesis. However, while all light within this spectrum is helpful to plants, it’s not all helpful in the same amounts.

Full Spectrum Grow Lights: Enhancing Plant Growth and Yield (1)

Full-Spectrum white-light LED

To mimic the look of natural light, full-spectrum LED grow lights include a large amount of green and yellow light. While these spectrums play a vital role in plant development, they are effective in considerably smaller amounts than red and blue light. The amount produced by white light LED manufacturers far exceeds the amount a plant can actually absorb, and more than 50% of that light winds up reflected from the plant’s surface. That wasted energy, in and of itself, is costing you money in power, but it also gets turned into heat, raising the temperature of the grow environment. This heat can have a detrimental effect on plants, and also forces the grower to invest money in additional cooling equipment and increase their watering schedules.

The horticultural lighting industry is overrun with white-light LED fixtures, and they are commonly found in commercial grow facilities. The primary reason these white light LEDs are so common is that white light diodes are already used in every industry imaginable for human visibility. The research and development into white light diodes is much further along—they are readily produced by several reputable companies, and because of this availability are considerably less expensive than producing a diode with a specially targeted spectrum. This means bigger profits for the companies using these diodes. Ultimately, manufacturing white light LEDs is a business decision that several companies have made, and marketing has spun a cost-saving measure into a selling feature, and has convinced a large percentage of growers that it’s a decision they should make as well along the way.


"Targeted" Full Spectrum Led Grow Lights

The facts dictate that Full-Spectrum grow lights may not be the ideal lighting solution for growing indoor plants. While we can’t argue that the sun does a pretty fantastic job of growing plants outdoors—one need only to look outside to see that it seems to handle the job pretty well—it’s a gigantic ball of endless nuclear energy that one wouldn’t necessarily want to bring inside their commercial grow facility. For one thing, the sun doesn’t have to worry about utility bills. So replicating natural light has the unfortunate side-effect of including quite a bit of the visible spectrum which simply cannot be absorbed by plants, and winds up simply being wasted—having a negative effect both on the grow environment and the grower’s pocket book.

This is where targeted-spectrum grow lights come into play. Targeted-spectrum grow lights, like the X2 from Kind LED Grow Lights, turn to light science to produce only the wavelengths of light that most benefit plant growth while avoiding the wastefulness that plagues the white-light LED market.

Full Spectrum Grow Lights: Enhancing Plant Growth and Yield (3)

Targeted-Spectrum Kind LED Grow Light

Decades of light science research have taught us some fundamental facts about how plants interact with light. We know that the blue part of the spectrum is most effective during the vegetative stage of a plant’s growth cycle, while red light is ideal for the flowering cycle. For this reason, reputable LED grow light manufacturers engineer their spectrum to focus on the parts of the spectrum that most benefit plants, not humans. Certain fixtures even allow the grower to adjust that spectrum throughout their plant’s life cycle, allowing growers unprecedented control over the growth of their plants.

Targeted-spectrum LED grow lights limit the amount of yellow and green light a fixture emits, which decreases the amount of energy wasted by the fixture, and consequently, the amount of heat produced. This in turn reduces the need for additional cooling measures needed in your grow environment, and can lower utility bills significantly.

Full Spectrum Grow Lights: Enhancing Plant Growth and Yield (4)

A grow room lit by targeted-spectrum Kind LED grow lights


Since the primary focus of targeted-spectrum LED grow lights is on the blue and red parts of the visible spectrum, the light produced looks purple, or even pink. Because of this, some growers have started to refer to these fixtures as “blurple” LED grow lights. While white-light LED manufacturers have long used this difference in appearance as validation that full-spectrum fixtures are ideal for grow environments, it’s important to remember that LED grow lights exist for the benefit of plants, not people. White-light LEDs may be easier to manufacture, and photograph better, but these are human conveniences. A targeted spectrum is much more beneficial to plants, and ultimately, that is what matters for growers everywhere, from home growers to commercial cultivation facilities.

In conclusion, while “full-spectrum” has historically been a bit of a vague term in the LED grow light industry, we can now definitely conclude that the benefits of these fixtures exist much more for humans than they do plants. Targeted-spectrum grow lights, on the other hand, have tremendous benefits for both humans and plants. They provide plants with everything they need for lush, healthy growth, and save growers a considerable amount of money while giving them complete control over the fixture’s spectrum. It’s safe to say that targeted-spectrum grow lights are truly the best of both worlds.

Full Spectrum Grow Lights: Enhancing Plant Growth and Yield (2024)

FAQs

Are full spectrum LED lights good for growing plants? ›

Modern LED grow lights producing a white, full-spectrum light are now capable of matching and even exceeding the yields of crops cultivated under HPS grow lights.

What is the best spectrum of light for plant growth? ›

While early LED fixtures focused entirely on red and blue light, more recent studies have revealed that full spectrum (white light—or red and blue light with yellow and green “filler”) produce more plant growth and better-quality produce.

Are red and blue grow lights better than full spectrum? ›

Full-spectrum LEDs are more adaptable but may not be as efficient for plant growth as red/blue spectrum LEDs. On the other hand, red/blue spectrum LEDs are more efficient for targeted plants but may not be as suitable for other lighting applications that require a broader light spectrum.

How much full-spectrum light do plants need? ›

Most flowering plants grow best with 20-30 watts of light per square foot. Don't make the mistake of thinking more is better. Too much light can lead to bleaching and burning your plants.

Can grow lights be too much for plants? ›

Too much light can also refer to the intensity of the light. Intense, direct light is great for some plants, but it will damage (or even kill others). The plant isn't able to convert all of the light into consumable energy, and the excess creates a heat issue over time.

How long to use full spectrum grow lights? ›

Is There A Limit To How Long You Can Leave Lights On? Short answer: yes. Even long-day plants need a daily respiration period of at least 6 hours (for seedlings) and ideally 8-10 hours for mature plants. We do not recommend providing more than 14-16 hours of light per day, even for long-day varieties.

Which color of the light spectrum is most important for plant growth? ›

Blue: This is the most important light for plant growth. It is easy for chlorophyll to absorb and convert into energy. Red: As the second most important wavelength, red light is incredibly potent for plants when combined with blue light.

How far should my LED lights be from plants? ›

The General Rule

For example, LED lights of 1000 watts are recommended to be placed 36 inches away from the plants. The lights can be lowered to 24 inches during the vegetative stage of the plant, and to 18 inches during the blooming or flowering stages.

What should I look for in a full spectrum grow light? ›

Good full-spectrum lights for indoor gardening have a CRI rating above 85, but the closer to 100, the better. Be sure to buy enough fixtures to evenly distribute the light over the entire area.

What color light is best for flowering? ›

So the first thing to understand is how each color influences your plants. In the most basic terms: Red light promotes flowering.

Do plants grow better under blue or green light? ›

However, there is still a lot we don't know about green light and how different colors on the light spectrum affect plants in general. A study conducted by Michigan State University found that blue light actually stunted plant growth more than green lights.

Should I get purple or red grow light? ›

Grow lights shine purple because they are arrays of bluish and reddish LEDs. Plants are most efficient at absorbing blue and red light to conduct photosynthesis, which results in sugars used for many of the plant's metabolic processes.

What is the best color for plant growth? ›

Red, blue, and white are good for all stages of growth of a plant and are generally the best unless you want to focus on one spectrum.

Can you leave a grow light on 24/7? ›

A: In general, you should not leave grow lights on 24/7. Plants need a light-dark cycle to develop properly. It's believed that they truly do “rest” during periods of darkness, and probably use this time to move nutrients into their extremities while taking a break from growing.

Is full spectrum light good for flowering plants? ›

Look for grow lights that provide a balanced spectrum of light that includes both blue and red wavelengths, as well as other important wavelengths like UV and infrared. In conclusion, full spectrum grow lights may be effective for vegetation, but they're not always the best choice for blooming and fruiting.

What LED lights are good for growing plants? ›

Green light in the 500 to 620 range is ideal for plants with thick growth cover, as it can penetrate top foliage for better light retention. Red light in the 600 to 730 range promotes flowering for later stage plants. Far red light in the 700 to 740 range is often used to speed the process of flowering.

How do you use full spectrum grow lights for indoor plants? ›

Place grow lights within a foot of the plant. Give plants at least 12 to 14 hours of supplemental artificial lighting; do not run them around the clock. Plants need a daily rest cycle. A high-quality, full-spectrum grow light, when used correctly, can substitute for sunlight.

Do full-spectrum lights have UVB? ›

Often incandescent household lighting products are sold as “Full Spectrum” even though they do not provide UVB or other essential lighting components.

What is the difference between LED lights and LED grow lights? ›

Grow lights and ordinary LED bulbs serve distinct purposes. While typical LEDs are for general illumination, LED grow lights are tailored for plant growth, replicating sunlight for indoor plants. They offer a richer light spectrum, emphasizing red, blue, and green, ensuring optimal plant growth.

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