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Color Spectrums and Growing Cannabis: Red/Far Red

Updated: Jul 1, 2021

Cannabis cultivation is way more than just watering, nourishing, and harvesting your plants. If you’ve grown cannabis for a while now, you know that paying attention to even the nitty-gritty specifications—like colors on the light spectrum—can completely change the outcome of your grow.

We’ve recently been taking a deep dive into the color spectrum and its relationship with growing cannabis, understanding just how differently each color affects the plant’s growth. Today, we’re focusing entirely on red and far-red lights, why we use them, and when. To help perfect your cannabis cultivations and get the most out of your special green plants, keep on reading.

The Impact of the Color Spectrum on Cannabis Cultivation

But, before we talk specifically about red lights and their impact on cultivation, let’s discuss the impact of light spectrums on cannabis cultivation as a whole.

The light spectrum is a way for us to understand how much lighting we’re being exposed to, and what type. Depending on atmospheric conditions, the amount of light that does reach us and our plants can change drastically, affecting a crop’s cultivation. The visible light spectrum emits colors ranging from blues to greens to yellows and reds. Each one of these colors represents a different amount of light reaching the Earth, and these varying amounts all affect cannabis growth differently. While we can’t necessarily pick up on all of these different light waves and color spectrum, our cannabis plants sure can.

As the sun shifts its direction in the sky, plants will be exposed to different colors on the light spectrum throughout the day. Thus, farmers work tirelessly to try to replicate this kind of changing of the color spectrums to help mimic what these plants would receive if they were planted outdoors. This also gets adjusted depending on what stage the cannabis is in in its life cycle, as different stages require different light variations to promote the best growth possible.

Every color on the color spectrum is going to invoke unique reactions within the cannabis plant, almost all of them being positive. While some colors are known for promoting deep stem growth and bigger, healthier leaves, other colors can help boost THC and terpene production— and who wouldn’t want that? However, doing this requires extensive knowledge of each color in the spectrum, when it should be used, and how. That’s why we’re here to help.

Let’s start with red and far-red lighting.

What Do Red/Far Red Lights Do?

Red or far-red lights are going to represent the furthest color on the color spectrum, making a color that the naked human eye can almost barely pick up. While the human eye cannot detect infrared light, our skin sure does! This is the type of lighting that typically reflects as heat. For plants, however, red lighting does a lot more than provide a little bit of warmth.

Scientifically, when cannabis plants absorb these red wavelengths, it triggers something biological in the plant, activating it into growth mode. Here, the plant is ready to start growing to its true potential during the flowering state.

In fact, many people rely on red or far-red lights to help shorten the flowering period of their plants, allowing for better growth and better potency. Instead of allowing these plants to slowly move their life cycles on their own, by manipulating lighting systems, growers can now control their cultivations more than ever. Red light has shown to seriously accelerate both root and flowering growth for cannabis plants and other fruits and veggies, making it an ideal color on the light spectrum for cultivation.

The Benefits

The utilization of red lights is typically more than just to replicate the natural colors of the light spectrum. In terms of cannabis cultivation, many people turn to using red or far-red lights because of the benefits/results they bring to a crop.

Studies have found that plants that were grown with the right amount of red light during flowering resulted in bigger, fuller plants with higher cannabinoid percentages. This is because a plant’s photosynthesis truly peaks during this much red light exposure, helping the plant to flourish.

In general, cannabis plants that are cultivated under red light during their flowering period tend to produce buds that are much bigger (and usually more potent) than those that didn’t. For cannabis cultivators, these large, powerful buds can make the difference between a successful crop and one that won’t sell. Thus, profit from red-light-grown buds can be quite significant.

As we mentioned earlier, red light manipulation can also be incredibly beneficial to growers as they can quite literally control when they want their plants to flower, rather than waiting for them to do it themselves. Because this type of color spectrum activates flowering within plants, growers can choose to utilize these colors whenever is most convenient/best for them. Not only is this wonderful for maximizing profit, but growers can also reduce downtime, eliminating the periods they normally would have in between grows. Instead, cultivation happens on your own time with light manipulation such as this.

When To Use Red/Far Red Lights

If you haven’t picked it up by now, the best time to use red or far-red lights is during the flowering period of your cannabis plants. The flowering period comes after your plant’s period of vegetation, and it’s when you expect to see those precious resinous flowers start to form on your cannabis. Up until this stage, you’ve probably seen quite a bit of plant growth from the cannabis plants themselves, but there hasn’t been a presence of buds quite yet. This is exactly what happens during the flowering stage.

So, as your plants are working hard to produce potent, fluffy buds, having the extra support of nourishing red or far-red lights can help propel these plants to where you want or need them to be. As we also mentioned above, exposing your plants to red lights during the flowering stage can help reduce flowering times significantly, as light is more concentrated and deliberate. If they went into the flowering stage naturally and relied on the color spectrums from the sun, this process can take weeks, even months.

Of course, not every grower will choose to purchase controllable red lights for their cannabis, and that’s perfectly okay. However, when used correctly, this type of color spectrum light can do wonders for your yield.

When purchasing red grow lights for your cultivation, make sure you purchase lights that not only work for your existing lighting setup, but ones that work for your plants, too. Always consider wattage, placement, and quality when purchasing colored lighting. Just because you have red lights doesn’t mean they’re being used correctly! Take the time to truly understand the best lighting setup for your cannabis and go from there.

Mastering the Color Spectrum for Cultivation

At the end of the day, having a solid understanding of the color spectrum can help you have a better relationship with your cannabis plants. The better of a relationship you have with your plants, the better your yield is going to be. Like we said, cannabis is complicated! Knowing how your cannabis reacts to different light waves can truly help you perfect your cultivation.

Luna Cultivation knows all about cannabis lighting and its importance. That’s why we’re here to help you master the color spectrum, too. We promise, though this kind of information will take a bit to get used to, it will completely transform your cannabis grow operation. From red lights to blue and every color in between, your cannabis plants are sure to thrive under your newfound cannabis lighting knowledge.

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