Why Do LED Grow Lights Give You Purple Light?

Did you know that the purple light that comes from an LED grow light can be more beneficial to your plants than the white or orange glow you get from HPS and MH bulbs?

The purple glow coming from LED lights is a combination of multiple wavelengths of light. This pinpointing of light is a major element of any LED light and their effectiveness on plants. It is important for growers to understand what causes this purple color and how it helps plants grow.

That’s why we’re going to explain what that purple glow really is and why you want it in your grow room.

What Makes an LED Grow Light Purple?

LED lights are made up of all kinds of wavelength combinations, and those combinations will create the light you give your plants. There's not just one wavelength of any given set of colors, though. LED's pinpoint specific wavelengths of light that benefit your plant and try their best to avoid offering wavelengths they don't.

LED Light Wavelengths

The combination of wavelengths LED grow lights offer is what gives us the light we see. Each wavelength of light has a nanometer or “nm” range and LED grow light manufacturers choose specific wavelengths to target growth. Here’s what those color ranges look like:

• Blue light wavelengths are between 450 and 495 nm.
• Red light wavelengths are between 620 and 750 nm.
• Ultraviolet wavelengths are between 100 and 450nm. There are three types of UV wavelengths, two of which are used in the grow room: UV-A and UV-B.
  • UV-C: 100 to 290 nm.
  • UV-B: 290 to 320 nm.
  • UV-A: 320 to 400 nm.
• Infrared wavelengths are between 700 and 1050 nm.

The purple color emitted by LED lights is caused by the combination of blue and red wavelengths of light that make up most LEDs. Studies show that these two wavelengths are critical in plant development, which is why manufacturers use multiple red and blue wavelengths in their grow lights.

Chlorophyll, the green pigment found in plants, absorbs and reacts to these blue and red wavelengths in order to perform photosynthesis — or to help them grow. What those specific wavelengths do for the plant once they’re absorbed, however, is vastly different.

Blue Light Wavelengths

Blue light wavelengths promote plant health by regulating growth. Plants exposed mostly to blue light tend to grow shorter and thicker, with shorter stems.

The leaves of these plants are a darker green color, and they’re much larger in size than those of plants that don’t get enough blue light.

Red Light Wavelengths

Red light wavelengths are equally beneficial to plant growth. Like blue light wavelengths, red light helps regulate growth. Typically, plants exposed to more red light grow taller with longer stems.

Red light wavelengths are also responsible for increasing the rate of photosynthesis in plants. It’s through a red light that plants are able to obtain the most energy.

Blue and Red Light Wavelengths Combined

Individually, these wavelengths stimulate different growth patterns. Blue light helps a plant’s growth, while red light helps with blooming and photosynthesis. When you combine them in LED grow lights they give your plants the light they need to stimulate all patterns of growth at the same time, which is exactly what your plants need to grow.

The combination of these two lights is also important because it allows the plants to follow a circadian rhythm. This means the plants will pretty much know when to perk up and when to rest, just as they would if they were outdoors feeding off the sun’s energy.

Together, blue and red light wavelengths provide the equivalent of a day-and-night cycle for plants. Because these plants would be grown indoors and aren’t exposed to actual sunlight, blue and red wavelengths remedy this.

The Benefits of Purple Light

Now that we know why specific wavelengths of light are used in an LED light, let’s talk about why that purple light is so beneficial to your plants.

HIDs shower plants with every wavelength possible, but purple LED lights isolate the specific blue and red wavelengths of light that benefit your plant. This is great for plants because it provides exactly what the plants need to grow and thrive, and it avoids giving them excess light that they’ll waste.

The ratio of red to blue diodes in a grow light will also benefit your plants. Whether you have more red than blue or more blue than red, you’ll get a lighter or darker shade of purple. Each shade has its own benefits, so you’ll want to find the right combination for your grow room.

For example…

• If you wanted better growth for taller plants, more blue wavelengths would be ideal, giving you a deeper purple look.
• For more leaves and better buds, you’ll need more red wavelengths, giving you a richer magenta glow.
• The addition of white or light-colored diodes will give you a pink/purple hue that encompasses wavelengths not usually found in other LED lights.

Best Purple LED Grow Light Brands

LED grow lights that offer purple lighting can drastically improve the way you grow your plants indoors. You can capitalize on the benefits of purple LED lights with various types of technology. Here, we’ll look at the different ways Advance Spectrum Max, California Light Works, and Kind LED give you their own blends of purple light:

Advance Spectrum Max

LED light panels from Advance Spectrum Max provide a magenta/pink light. This shows that it offers a wide spectrum of light, ensuring that your plants get the correct wavelengths of light they need for vigorous growth throughout an entire grow cycle.

Aside from the multiple blue and red light wavelengths, Advance Spectrum Max LEDs like the S900 Advance Spectrum MAX LED Grow Light Panel also include an isolated infrared diode. This IR diode is great for quality resin production, which gives you richer flavors and scents.

California Light Works

California Light Works LED lights are great for regulating the amount and type of light your plants receive. Not all plants need the same ratio of blue to red light as others, so it’s helpful to be able to control how much of which wavelength your plants get.

The California Light Works SolarSystem 1100 LED Grow Light, for example, allows you to change the intensity of the blue, red, and purple wavelengths to dial in the specific lighting your plants need. While the spectrum range may be limited, they still offer what your plants need for vegging and flowering growth.

Kind LED

While not programmable, Kind LED grow lights are some of the most powerful LEDs on the market with one of the widest spectrum ranges. The Kind LED K5 Series XL1000 WIFI Indoor LED Grow Light, for example, uses a 12-band spectrum that implements ultraviolet (320 nm) and infrared wavelengths.

You’ll get everything you need out of a Kind LED light, though at a much higher price point than Advance Spectrum Max.

Purple Lights in Your Grow

Purple lighting isn’t just for show like some think. Whether you’re working with deep purple light, a lighter magenta, or an even light pink light, these combinations of wavelengths ensure your plants reach their peak potential. The chlorophyll in your plants will absorb this purple light effectively much better than the white and orange light your plants receive from HIDs. Instead of spending time-wasting light, your plants focus on absorbing everything they need in order to give you the harvest you want.