Can You Use Any Red and Blue LED Lights to Grow Plants? (2024)

You’ve done your research on color spectrum for plant cultivation. You know blue light is essential for growth and development. You know red light promotes flowering. You know LED grow lights are most efficient. Now as you look at your options, you wonder: “Can I just use blue and red LED lights? Do I need all this extra research.”

The short answer: No, you can’t, and yes, you do. While the color spectrum is essential for expert cultivation, it is not the only factor that can make or break your operation. Here’s a quick guide for choosing the right blue and red lights so you can narrow down the possibilities.

Why Your Plants Need Blue and Red Light

First, let’s cover some light spectrum basics.

In order to thrive, your plants need plenty of photons that fall within the PAR range. PAR refers to “photosynthetically active radiation.” In short, these are the wavelengths your plants actually use for photosynthesis.

The PAR range spans from 400 – 700nm. Blue light sits at one end of that spectrum, while far red sits at the other.

As you know, blue light is a major player in the vegetative phase. Blue promotes root development and strong, stocky plant growth. When you blast your young plants with blue, you prepare them to sustain a ton of buds in the future.

Red light, on the other hand, does its best work in the flowering phase. A higher intensity of red promotes a higher yield.

It follows, then, that you do need light sources can provide both the red and blue light spectrum. But red and blue are only the beginning. There are a few more considerations that help you choose the right lights.

Why Intensity Matters

It isn’t enough to give your plants light within the PAR range. They need to get enough of that light to thrive. This is why you can’t just screw in a blue incandescent light bulb and call it a grow room.

Look at this way. In nature, plants get all their light from the sun. That is some high intensity light. If you plan to in a grow room or a grow tent, you have to provide the light spectrum your plants would get from the sun and deliver enough photons to support photosynthesis.

In the language of indoor cultivation, what you’re looking for is PPFD. PPFD stands for “photosynthetic photon flux density.” This measurement tells you the amount of usable light (PAR) that actually reaches your crop when you use a given grow light.

If you’re growing a flowering plant, you need around 300 – 600 umols for the vegetative phase and 800 – 1,000 umols for flowering. That’s a high PPFD, and it narrows your options for grow lights considerably. The two likeliest places to find the spectrum and intensity you need are:

  • Blue and red HID lights
  • Blue and red LED lights

So which of these is the best option? Let’s take a look.

Blue and Red HID Lights

HID (high-intensity discharge) lamps used to be the preferred option for indoor growing. The greatest benefit of these bulbs is right there in the name: high intensity.

However, HID bulbs are not full-spectrum lights. In order to accommodate the needs of their plants, HID growers have to switch between two different bulbs. During vegetation, they use MH (metal halide) lights, which radiate light in the blue spectrum. For the flowering phase, they switch out MH bulbs for HPS, which favors red light.

For years, this method has been the most effective way to promote healthy plants and substantial yields. But now, the landscape of grow light technology is changing. Blue and red LED lights are fast becoming the number one choice over MH and HPS bulbs.

Here’s why.

Blue and Red LED Lights

In recent years, LED grow light technology has advanced to the extent that LED lights provide the greatest benefits to both plants and gardeners.

LED grow lights easily match the intensity of HID bulbs. They radiate that essential blue and red light. And high quality LED grow lights accomplish this while also:

  • Consuming half the energy of HID bulbs
  • Emitting almost no heat (thus protecting plants and minimizing cooling costs)
  • Lasting 50,000+ hours with very little decline in light quality
  • Requiring no ballasts or complicated installation process

Plus, most LED grow lights are designed to switch between the blue and red spectrum. One fixture does it all. You never have to change a single bulb.

Now, this all explains why LED grow lights are easier to use and more cost-effective in the long run. But it’s also worth considering how the highest quality LED grow lights set new standards for the ideal color spectrum.

…and why it’s not in your best interest to just grab the least expensive blue and red LED lights you can find.

The Benefits of Full-Spectrum LED Lights

Blue and red light are so essential that they’re almost all you hear about when you’re new to cultivation. The problem is that these are not the only colors your plants use within the PAR range.

While your plants get the most use out of red and blue, colors in the middle of the PAR range also serve a purpose. Green light, for example, penetrates the canopy better than the rest of the color spectrum.

The best LED grow lights provide the exact spectrum your plants require . . . and only that spectrum. This ensures your crop gets everything it needs and no light goes to waste.

One great example of a full spectrum LED grow light is the SolarXtreme series by California Lightworks. Every lamp in this collection includes the exclusive Optigrow spectrum, tailored specifically to the needs of your plants.

Serious growers may even want to kick their game up a notch with variable spectrum LED lights, like the SolarSystem series. A variable spectrum LED allows you to adjust color levels.

There are countless benefits to having that kind of control. By manipulating the spectrum, you can usher your indoor plants through the grow cycle at a faster rate. You can make nuanced adjustments to your light recipes in real time, depending on how your plant responds.

You also don’t have to choose between strictly blue or red LED lights. Instead, you can create a more natural ratio of red to blue LED light, promoting higher yields and a more flavorful harvest.

The more LED technology evolves, the greater your options become.

The Importance of Choosing the Right LED Grow Light Manufacturer

It’s easier than ever to find low-cost blue and red LED lights on Amazon or Ebay. The problem is that these lamps are not coming from a reliable manufacturer who understands the science of indoor grows.

Rather, these are cheap LEDs made in China. They produce a vastly inferior light quality, they break in a matter of weeks, and they may not even be safe.

There is also absolutely no chance that these budget manufacturers could even begin to answer your questions. It may cost more in the immediate future to choose a reputable LED brand, but you’ll get both the quality and customer service you need to support a healthy crop.

Where to Find the Best Blue and Red LED Lights

Even once you’ve decided to bank on the benefits of full-spectrum LED lights, you still face the challenge of choosing the best LED grow light for your setup.

We recommend starting with either the SolarXtreme series or SolarSystem series by California Lightworks. The SolarXtreme series provides full-spectrum lamps that are both high powered and hobbyist-friendly. The SolarSystem series is also easy to use, but the technology is more sophisticated and provides variable spectrum control.

If you need any help navigating these options, please let us know. We understand how daunting the light selection process can be, and we’re happy to help growers however we can.

Can You Use Any Red and Blue LED Lights to Grow Plants? (2024)

FAQs

Can You Use Any Red and Blue LED Lights to Grow Plants? ›

Tips for Using LED Grow Lights Effectively

Can I use any blue and red LED light to grow plants? ›

Typically, if you are in a greenhouse, you should be using LED luminaires with an optimized red/blue spectrum, since they are most efficient at converting electricity into useable light for plants.

Can I use any LED light for growing plants? ›

The Bottom Line. Ideally, you'd use a special LED grow light for your plants. While they require an initial investment, they are the most energy-efficient way to provide your indoor plants with full-spectrum light. If you already have other full-spectrum LED lights in your home, they can serve as a viable alternative.

Will any red light work for plants? ›

Red Light (620nm-700nm)

It can greatly enhance the photosynthesis of plants and promote the growth of plants. but if plants are grown under only red light. They will have a stretched and elongated appearance. The leaves are long and thin and plants become tall.

What is the best ratio of red to blue LED for grow lights? ›

LED light may improve both productivity and nutritional quality. Nitrate level in leafy vegetable is reduced by LED application. Red:blue ratio of 0.7 is needed for proper plant development.

Is too much blue light bad for plants? ›

Generally, blue light suppresses extension growth; plants grown with blue light are usually shorter and have smaller, thicker and darker green leaves compared to plants grown without blue light (Figure 1).

What color LED light do plants like? ›

Horticulture lighting primarily focuses on red and blue wavelengths. These are the two most important colors on the visible light spectrum for promoting plant growth. That is why products on the horticulture lighting market often give off a purple glow—it is from the combination of red and blue light.

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

While general-purpose LED lighting will give off white-light illumination, grow lights will produce greater amounts of red and blue spectrums which are ideal for stimulating photosynthesis in plants.

Do regular lights work for plants? ›

Typically, incandescent and halogen lights are not recommended as grow lamps because, while they do often offer full spectrum lighting, they operate at a very high temperature that can easily damage foliage. They are also inefficient in terms of energy usage, and are being phased out by governments worldwide.

Do purple LED lights help plants grow? ›

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.

Can too much LED light hurt plants? ›

Plants can experience light burn or stress when they receive too much light or when the light source is too close to the canopy. Symptoms of light burn include leaf curling, bleaching, or brown spots on leaves. To prevent this, maintain a safe distance between the LED grow lights and the plant canopy.

Do plants absorb red and blue light? ›

In plants, chlorophyll a and chlorophyll b are the main photosynthetic pigments. Chlorophyll molecules absorb blue and red wavelengths, as shown by the peaks in the absorption spectra above.

What color light do plants not grow best in? ›

Green light is generally reflected away from plants (which is why they appear green), but plants will absorb a small amount of green light throughout the photosynthesis process. Yellow and white light have the lowest effect on plant growth.

Are red and blue LED lights good for plants? ›

Blue promotes root development and strong, stocky plant growth. When you blast your young plants with blue, you prepare them to sustain a ton of buds in the future. Red light, on the other hand, does its best work in the flowering phase. A higher intensity of red promotes a higher yield.

Why do plants grow better in blue light than red light? ›

The more blue light, the wider they open their stomas, so accelerating their metabolism. High levels of blue light will therefore promote increased metabolism, and by extension accelerate plant growth and development. Blue light is also responsible for directing leaves and growth points toward the light.

What LED color is best for germination? ›

630-660 nm (Red) Light: This light is essential for germination and stem growth, as well as leaf expansion. It is also used to regulate periods of growth and flowering. Too much red light, or red light used alone, will produce tall plants that appear stretched with thin leaves.

Can you use a color changing LED as a grow light? ›

Generally LED lights do not provide the best color spectrum for plants and are not comprehensive like that as grow lights. For instance, plants require a red and blue spectrum for their growth and survival, but LED lights are unable to provide this spectrum.

Are all LED lights full-spectrum? ›

Not all LED light bulbs are full-spectrum lights. Some LEDs may use different color diodes such as green, blue and red, though this doesn't make them full-spectrum lights. That said, there are numerous LED full-spectrum lights in the market today.

Is blue or red light better for photosynthesis? ›

The proteins of chloroplast sub-compartments under blue LEDs at high light intensity optimize photosynthesis and provide an advantage for higher growth and development of plants than those grown under red and green LEDs at low light intensities.

Is red or blue light better for germination? ›

Red light promotes seed germination, while Blue light and low Red/Far−Red ratio conditions inhibit seed germination.

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