Harnessing the Infrared Spectrum for Best Agricultural Practices

Plants requiring light for growth is an established truth within the agricultural world. Ask any grower out there, and they will all agree that the correct use of light is paramount to achieving the best crop yields while simultaneously keeping sustainable practices. However, in recent years, advancements in science and technology have made us debate the exact effect of light on plants. Here, the infrared (IR) light spectrum is one that generates lots of discussions.

Infrared light is an invisible part of the electromagnetic spectrum, yet it has many applications in our daily lives. Growing environments thrive with artificial lighting, a light that seeks to provide as much energy as sunlight, if not more. LEDs, in particular, are the ones growers most frequently choose to work with because they are energy-efficient and provide a more comfortable work environment. Thanks to its constant innovations and wide light spectrum, the LED has become essential in indoor horticultural lighting.

IR LED grow lights can have a wide range of applications during the different stages of a plant’s growth cycle. Infrared LED grow lights are becoming increasingly popular in indoor growing environments because of how suitable they are for plants. When it comes to grow lights for flowering plants, infrared is what you want to use. But what amount of it do we need? Does it work well with all the plants? Is it safe for us?

In this article, we’ll talk about IR grow lights in-depth and discuss everything related to the effect of infrared radiation and the possible benefits it can have on our agricultural practices.

Understanding the Importance of Infrared Light for Growing

There are a few things we need to establish about the effect of infrared light on plants. Plenty of growers out there are already acquainted with the advantages of the different colors of the light spectrum. For example, it is well known how blue or violet light (400-500 nm) can be vital for the vegetation stage, while red or orange light (600-700 nm) can have tremendous results during the flowering stage. These light spectrums are perceptible to the human eye as their wavelengths are on the visible part of what our eyes can see.

Nevertheless, plants also require light beyond the spectrum of what we can see. Both the ultraviolet (below 400 nm) and infrared (above 700 nm) spectrums can have applications in the agricultural world. Consider the ultraviolet range (200 – 400 nm) for a second. This spectrum of light has the shortest wavelength but a lot of energy. Ultraviolet light can be stressful to plants, cause sunburn on human skin, and be highly damaging to human eyes, especially at the shortest wavelengths.

Yet studies have demonstrated how beneficial ultraviolet light can be for cannabis plants. Cannabis tries to counter the stress of the ultraviolet wavelengths by creating its own sunscreen with trichomes. Specific wavelengths of ultraviolet light can also boost terpene production in this plant. Using the right amount of ultraviolet light can result in cannabis with an improved aroma or a better quality oil for producing edibles, tinctures, or waxes.

On the other end of the light spectrum, we can find the far-red and infrared wavelengths (over 700 nm). The main characteristic of the light under this spectrum is that it has very long wavelengths and very little energy. These wavelengths are imperceptible to the human eye. Nonetheless, they manifest themselves as heat.

Using this spectrum of light in conjunction with others can result in:

• An increased photosynthesis rate due to the Emerson effect
• The regulation of the phytochrome proteinthat controls when a plant switches between its vegetation and flowering stages
• A more robust stem growth
• Better node spacing
• An improved yield of flowers and fruits in general

This wavelength can also have adverse effects on a plant if misused. Therefore, choosing the right amount of infrared light is crucial to ensure your plants grow healthy.

What Is Infrared?

As mentioned above, infrared light is a part of the electromagnetic radiation spectrum. These specific wavelengths are longer than those of visible light. The IR light wavelength is between 700 nm to 1,000 nm. These wavelengths are invisible to human eyes; however, they are the primary way heat transfers from one source to another. The longer these wavelengths are, the more heat they produce. These wavelengths lie in the lower-medium range of frequencies, between what would be microwaves and radio wavelengths and visible light.

A hot object emits infrared radiation. We cannot see this “heat” with our eyes, but we can feel it in the form of warmth. Instruments like infrared cameras and night vision goggles can detect this “heat” from surroundings and showcase these emitted waves. The human body naturally gives off heat, and an infrared camera can capture this. If an object is at absolute zero or has no temperature whatsoever, it doesn’t emit any infrared radiation.

It’s worth mentioning that the closer these wavelengths are to the microwave range, the more they will manifest themselves in the form of heat. A longer wavelength produces more heat, while a shorter wavelength does not generate much of it. Having these wavelengths absorbed or reflected depends entirely on the nature of the object. Water vapor, stone, and wood can absorb infrared light, while gold, silver, and aluminum reflect it instead.

The infrared range consists of the following wavelengths:

• Near-infrared

These are the shortest in the infrared spectrum. This wavelength is the closest to the visible light range. It can be seen in some everyday objects such as TV remote controls as well as photography and communications applications. These lights are not hot.

• Mid-infrared

These are warmer than the near-infrared range but are still not considered hot. These wavelengths can find extensive application in special equipment scientists use to study planets and other objects in space.

• Far-infrared

These wavelengths are hot and are typically found in grow rooms to help plants develop better.

The Emerson Effect

Using both red and blue light is vital for plant growth. However, when combined with infrared light, it can boost the rate of photosynthesis through an effect known as the Emerson effect. Two chemical procedures inside a plant contribute to its growth. These processes are known as PS I (photosystem 1) and PS II (photosystem 2). Plants exposed to blue and red light, along with infrared light, can get a boost to their photosynthesis process. Similarly, when these wavelengths are not present, their growth is slower.

Robert Emerson first discovered this in 1957. He realized plants receiving light below the 680 nm range had a slower photosynthesis process. Later, he found that when plants received infrared light at 700 nm and slightly above, they started to produce adenosine triphosphate (ATP). This compound is what plants and animals use to store energy.

He then noticed that when plants received both lights at the 680 nm and 700 nm wavelengths, their photosynthesis was far greater than when used individually. Emerson then concluded that there were two separate photosystems at work inside the plant. He also realized effective photosynthesis needed both of them to be active.

PS II uses the smaller wavelengths to separate water into ions to produce electrons. Then, PS I uses these electrons alongside the longer wavelength of light to create the ATP compound to store energy.

Effects of Infrared Light on Plants

Infrared lights for plants can have positive results since they encourage growth. Plants under the effect of an infrared LED grow light can have their stem growth speed affected. Additionally, brief exposure to infrared grow light can increase node spacing. Research shows that the infrared spectrum can influence the blooming phase of plants due to the presence of photoreceptors known as phytochromes. These photoreceptors are essential for how a plant develops, affecting the expansion of leaves, the blooming, and the growth of the stem.

The phytochromes of a plant spend all day receiving light, and their structure changes depending on how much light they receive. They bestow upon plants the ability to know what season they are in and the time of day. With this, plants are able to regulate their growth. Using infrared light for plant growth is the best way to trick a plant’s senses to speed up its growth process. Delivering the right amount of infrared effect will make the plant “think” it is receiving the same amount of light as it was growing outside on a sunny day.

An extra notable benefit of exposing your plants to infrared plant light is the increase in growth. Plants depend on sunlight for their photosynthesis. When their sunlight exposure diminishes, this activates a defense mechanism that makes them stretch and grow in search of light. When your plant receives a high level of infrared light, say, from an IR light bar, this triggers the plant’s defense mechanism, thus, stretching and growing further.

Flowering and fruiting will appear more rapidly when using an IR LED grow light. If a certain plant typically takes 12-14 days to start flowering or fruiting, adding a short time of infrared light at the beginning of its dark period will reduce this process to 7-10 days. Once the infrared light is in place for 15 minutes after the main light has gone out, this can make the plant “think” the dark period is longer, changing their light-on period in the process.

The implication of this change of light and dark times is that the flowering or fruiting period will shorten by a couple of days. As a result, this makes infrared lamps the best lights for the flowering stage of plants.

How Infrared Light Works on Various Grow Lights

When it comes to grow lights for flowering, three types of commercial lights are common among growers: HID, LED, and T5. These are the three most prominent fixture configurations used for indoor gardening. All three of them are capable of providing infrared radiation. Let’s look at each one more closely:

• HID

These light fixtures get their power from gas and are standard in labs and indoor gardens. These lamps contain gas, metal salts, and two electrodes inside them. When the electricity arcs of the electrodes meet with the gas inside the tubes, it creates light. About 30% of the light they generate is infrared radiation. Depending on the gas type, they can produce light from different spectrums. For example, metal halide lights have a white or blue color, while high-pressure sodium lamps project a warm yellow or orange light.

• LED

Do LED grow lights have infrared? Yes, they do. LED flowering lights are among the most demanded nowadays. These lights consist of several diodes, some of which can produce infrared light. These LED IR lights frequently only deliver visible light in the blue and red spectrums. However, thanks to the added infrared emitting diodes, they can also provide infrared light to plants to boost their growth. Using LED for flowering is a common practice for growers worldwide nowadays.

• T5

Similar to HID lights, T5 fixtures produce light with an electrical current and a chemical reaction. When it comes to flowering lights, the T5 fixtures are seldomly used because they don’t provide as much infrared energy compared to LED or HID. You can, however, incorporate LED IR lights or buy separate light bulbs for this fixture to compensate for the missing IR. These lights are usually more compact than the other two, making them a great option when growing space is a concern.

Things to Keep In Mind When Using Infrared for Plant Growing

Here are a series of key points you should consider if you want to implement IR lights into your indoor garden operation:

• Plants need an ideal grow room temperature, balancing all heat and light sources according to their need. Growers should place their plants strategically to ensure they get the optimal light intensity and are away from excess heat.
• Consider that plants with larger biomass are prone to absorb more radiant heat. This bigger biomass is characteristic of plants that produce large fruits. When these plants grow and mature, they absorb more infrared radiation during their flowering, budding and fruiting phases. This consideration is crucial in annual species of plants that mature during the fall season when temperatures usually get lower or in heat-sensitive plants.
• Don’t subject your plants to huge amounts of PAR photons and infrared radiation because this can generate heat stress, causing more harm than good in the plant’s development. It can cause the leaves to curl downward or to turn brown and dry. Photosynthesis rates also take a major downturn as the stomates on the leaves close to conserve water.
• Consider how much space you have in your growing area for your plants to stretch out and grow. Infrared light plant growth can be quite a thing to behold. Infrared light triggers the plant’s natural defensive mechanism to stretch and grow, so make sure you have room in advance when you introduce IR to them.
• Just as excessive exposure to IR can cause damage to your plants, it can be dangerous for you too. If you’re using infrared lights, monitor your exposure to them and use protective equipment to prevent heat or burn damage on your skin. When using LED IR grow lights, plants should be placed further away than usual so that they don’t get any heat damage from the light source.
• Cost is always a vital factor to contemplate. These lights are not mandatory for your plant’s survival or development and instead act as a boosting agent. However, since they can introduce additional heat into your growing environment, you may need to install a specialized HVAC system to regulate the heat from your IR grow light. This system can be costly to install and maintain, so take all the necessary wallet considerations and see if the benefits are worth it.

Finally, your plant’s specific needs should go above anything else. Infrared light has the potential to make your plants grow and bloom, but this will depend on the type of plants you grow, as the effect can be more pronounced in one over others. Check the amount of IR energy each plant in your garden can handle and if it is worth it.

Final Words

So, the big question is: do plants like infrared light? As with many things in life, it depends. Infrared lighting does carry several advantages for indoor growing: adequate node spacing, improved plant growth, and shortening of flowering and fruiting phases. At the same time, excessive exposure to IR can be damaging if the wavelength is not fit for the plant’s needs or if the heat generated by the light fixture creates too much stress on the plant.

What’s vital is to make sure your plants get the proper doses of infrared radiation by controlling their exposure and finding the perfect position for both the lights and the plants in your garden. Infrared light is mainly supplemental, but its advantages are enough to warrant an investment if you want to improve your growing operation. Consider an infrared LED grow light for your indoor garden and start harnessing this invisible spectrum to give your plants a significant boost!

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