We all know that plants need light to survive and thrive. Growing plants indoors can be difficult if there has been insufficient natural light, necessitating the use of artificial sources. While even normal light bulbs can help a plant grow, the results are not as satisfactory as using grow low bulbs.
More recently, advancements in lighting technology have created something of a revolution when it comes to indoor plant cultivation, with artificial lighting systems replacing sunlight and allowing for year-round cultivation in controlled environments.
Most households are now using Light-Emitting Diodes (LEDs) in place of standard incandescent bulbs Compact Fluorescent Lights (CFLs). But your regular LED light you use to read a book or light your bathroom are different from those used by indoor growers, both professional and hobbyist.
What makes LEDs popular for modern indoor plant lighting and what is the science behind them? Keep reading to learn more and to receive some tips on optimizing growth using LEDs.
What Are LED Lights? A Brief Overview
Have you ever wondered how the magic of LED lights work? No? Well, then skip this section and read about the benefits of LEDs for indoor growing—that’s where it gets most interesting! But, if you want to impress your science buddies, then here you go. LEDs are semiconductor devices that emit light when an electric current passes through them. As electrons in the semiconductor recombine with electron holes in the semiconductor material, energy is released in the form of photons, or light particles. This process, called electroluminescence, differs from the incandescence used by standard bulbs.
Electroluminescence is a highly energy-efficient process, as most of the energy it uses is turned into light, whereas incandescence converts the energy into heat, which in turn produces light.
LEDs are not new technology, having been with us for nearly a century, though the first practical LED was developed in the 1960s. Early LEDs emitted low-intensity infrared light and were used in remote control circuits, finding their way into many consumer electronics. Visible-light LEDs followed, which were also low in intensity and limited to the colour red. These were often used as indicator lights, such as power buttons or standby lights in devices such as TVs and radios.
As the decades passed, advancements in manufacturing techniques and semiconductor materials produced more powerful and efficient LEDs. In the early 1980s, the first generation of super-bright red, yellow, and green LEDs were produced. By the early 1990s, experimentation with new semiconductor materials resulted in ultra-bright orange-red, orange, green, and yellow LEDs. Then in 1994, Shuji Nakamura created the ultra-bright blue LED, followed by high-intensity blue and green LEDs. It was then discovered that by coating the blue LED with fluorescent phosphors, the diode could emit a bright, white light, creating the LED bulbs that are in common usage today.
Benefits of LED Lights for Indoor Growing
Indoor grow lights have been around for many years, but older bulbs presented various challenges, such as excessive heat. Continual innovation has brought us the LED lights that are the choice of today’s growers. Here are some of the benefits that they offer:
Energy Efficiency and Sustainability
One of the major advantages offered by LEDs is their energy efficiency. It is this trait that has made them popular with both homeowners and growers. Traditional lighting systems are known for their much higher energy consumption. LED lighting lets you produce as much light or more, while using significantly less energy. This has the advantage of not only reducing your monthly energy bills, but also contributing to a greener, more sustainable future for all by lowering your carbon footprint.
Targeted Light Spectrum
LED lights are customizable, which means you can use them to emit specific light wavelengths, allowing LED lighting to mimic the natural spectrum of sunlight. This is a vital concern for your plants because they require different wavelength through their various stages of growth for peak development.
Blue light, for example, is responsible for promoting vegetative growth, or the growth of leaves, roots and stems. Red light is used to enhance the plant’s flowering and fruiting for a better yield. Balanced spectrum lighting is critical for the overall health of your plants.
Because they are adjustable, LED lights can be fine-tuned to meet the specific needs of each stage of growth. This will help ensure optimal growth and development for your indoor plants.
Longevity and Durability
Aside from their reduced energy consumption, one of the more notable features of LED lights is their longevity. They have an impressively long lifespan compared to other, traditional grow lights. Typical lights, even those touted as long-lasting, need frequent replacement. High Pressure Sodium lights, for example, last about 24,000 hours, but because they tend to become less efficient with time, many growers will find themselves replacing them before they reach the end of their lifespan. LED lights typically last up to 50,000 hours but may serve longer depending on the model and quality.
This remarkable longevity means less time changing bulbs and lower expenses due to less frequent replacement. Even better, the LED bulbs produce a consistent light quality through their lifespan, meaning they can be used until failure. They are also more resistant to shock and vibration so they are less likely to be damaged from handling and transportation.
Flexibility and Control
Of significant importance is the ability to customize LED lights, giving them flexibility that is unmatched by any other grow light. Both the intensity and spectrum can be tailored to the needs of the plant, allowing growers to adapt lighting conditions as necessary to produce the best possible results. By producing light through electroluminescence rather than incandescence, LED lights have low heat emission. This means they can be placed in close proximity to the plant without fear of scorching or otherwise damaging sensitive foliage. As a result, light absorption is maximized, and growers are able to make effective use of vertical growing spaces.
Comparing LEDs to Traditional Grow Lights
Although we have already covered several benefits of LED lights, let’s take a moment to compare LED to traditional grow lights in a more comprehensive manner:
High-Intensity Discharge (HID) Lights
Metal Halide and High-Pressure Sodium are two examples of high-intensity discharge lights. These are a type of lighting that create light by sending an electrical discharge between two electrodes. This creates an electric arc between the electrodes, passing through an ionized gas. This arc heats metal salts within an arc tube, typically made of quartz, creating a plasma. This greatly increases the amount of light produced by the arc.
HIDs are more efficient than traditional technologies such as incandescent bulbs at producing visible light rather than heat, though they did still produce a significant amount of heat, necessitating cooling measures, which added to operating costs.
HIDs were widely used in interior growing prior to the advancement of LED technology, but their limited spectral control mean that growers had some difficulty in tailoring the light spectrum to match the growth stages of their plants.
Compact Fluorescent Lights (CFL)
CFLs are a more energy-efficient alternative to HID lights. They rely on gas reactions inside their tubes to produce light. These tubes contain argon and mercury vapour, and the inside of the tube is painted with a fluorescent paint. When activated, the internal ballast sends current though the tube, exciting the gases, which creates ultraviolet light. The UV rays are then absorbed by the fluorescent paint, which emits visible light.
Despite the reduction in energy usage, CFLs still consume more than LEDs and they produce a lower light intensity with a less focused light spectrum. Because of this, they are not as effective as LEDs in promoting healthy plant growth. This is particularly noticeable in tall and densely packed plants.
CFLs are best suited to small-scale or low-light plants and see relatively little use in large-scale growing operations.
T5 Grow Lights
Another option for indoor horticulturalists is the T5 grow light, a type of fluorescent bulb that is more efficient than traditional fluorescent lights, such as CFLs, though not as energy efficient as LEDs. The T in T5 stands for “tubular” while the 5 indicates a 5/8-inch diameter. Other types exist, such as T8 and T12, but the T5 is the most popular.
T5 are known for providing uniform light distribution, which makes them a good choice for seedlings and younger plants. Where they fall short of LEDs is in their lack of spectrum customization and intensity control.
Tips and Tricks for Optimizing LED Growth Performance
LED technology has revolutionized the way plants are grown indoors with the ability to control the spectrum of light and greater energy efficiency. To get the best results, here are some tips and tricks for optimizing LED plant growth:
Positioning Your LED Lights
Proper positioning of your LED lights is an important part of ensuring uniform growth. The distance between the light and the plant affects the light intensity received by the foliage. Monitor your plant’s response carefully. If the plant seems to be stretching toward the light excessively, the lights may be too far away, or the intensity may be insufficient. LEDs produce much less heat than other lights and are therefore the safest to have in close proximity, but even they can damage the plant if too close. Signs of light burn include bleaching and leaf damage, indicating that the light is too close or too intense. Monitor your results and adjust the height accordingly, making adjustments as the plant grows.
Managing Light Intensity and Duration
LED grow lights offer you control over light intensity, giving you the ability to tailor the output to the growth stages of your plants and their light requirements.
During the plant’s vegetative state, they are developing leaves and stems, making higher light intensity beneficial. Once they begin to transition to a flowering stage, lower light intensity is normally preferred, promoting bud formation and preventing light stress.
Intensity is only one factor to consider, however, with duration also playing a role. Different plants have their own requirements for the amount of light needed each day. Some may need longer days of up to 18 hours, while others might flourish with only 12 or 14.
You will need to find the right balance between intensity and duration of light exposure. Using automated timers or smart lighting systems are useful for regulating the light duration. Keep in mind that periods of complete darkness are also required.
Balancing Light with Other Growth Factors
While light is an essential part of your plant’s survival, there are other requirements as well, each of which you should be monitoring. For example, you should be maintaining the right humidity and temperature levels in the grow space. Stress and reduced growth can result from high temperatures, while low temperatures may slow down metabolic processes.
Water, nutrients, and air are also key components for your plants. Water is an obvious need, but LED lighting enhances the efficiency of photosynthesis which can result in a greater demand for nutrients. Proper air circulation can help prevent mold, mildew, and pest infestations, while distributing CO2—essential for photosynthesis—throughout the grow space.
Balancing all these factors according to the needs of your plants will give them the ideal growing environment.
Real-life Successes: Case Studies of LED Grow Operations
There have been several real-life case studies showing the success to be had using LED lights for indoor horticulture. Commercial growers and researchers have reported not only higher crop yields, but also improved crop quality. Combined with the reduction in operating costs, the benefits of LED lights for indoor growing are clear. Other case studies demonstrate how LED lights can be tailored to suit specific crops and even cultivation methods.
If you are looking for in-depth information about the effects of LED grow lights, Hort Americas provides several case studies and trial information. One such case is that of Atlantic Grown Organics on Prince Edward Island. As a family operation, they were seeking ways to lengthen their growing season as winter approached and days grew shorter. Their first crop of tomatoes thrived with the new lights.
Although they had some experience with LEDs, they decided to update their lighting system to gain more control of the light spectrum. According to owners Marc Shurman, who runs the operation with his wife Krista and their three children, “the lights… made our growing season more productive and, as a result, allowed me to focus on what I do best—feeding people throughout the Maritime Provinces.”
Getting Started with LEDs: What to Look for When Purchasing
If you are looking to buy LED lights for your indoor plants, here are some tips to help you with your purchase:
Wattage and Coverage
Start by considering the size of your growing space and the number of plants you intend to cultivate. This will help you select lights based on the wattage and the area they can effectively illuminate so that they match your specific needs.
The LED grow lights that you select should offer customizable spectrum options or full-spectrum capabilities. The former lets you tailor the light according to your needs at each growth stage, while the latter offer a balanced combination of red, blue, and other wavelengths to support all growth stages.
Cooling and Heat Management
We’ve mentioned above that LEDs produce less heat than traditional grow lights, but that heat can still be a factor. Proper heat management, along with being beneficial to your plants, will also help to maintain optimal performance and longevity. The grow light that you choose should have adequate cooling to dissipate excess heat.
Brand Reliability and Reviews
A little research can go a long way. Look for reviews of the brands and models that you are considering and seek out feedback from other growers who are familiar with the products. They will be a valuable source of information about longevity, reliability, and performance. Invest in the brands that have positive reviews to be sure that you get the highest quality lighting system possible.
The Bright Future of LED in Indoor Horticulture
There are many good reasons why LEDs are gaining in popularity, both for general lighting needs and for indoor horticulture. They last longer, save you money by using less energy, give off less heat, and are an excellent means of facilitating sustainable plant cultivation. Their energy efficiency, combined with their targeted light spectrum, adjustable intensity, and overall flexibility make them the obvious choice when selecting a lighting system for indoor growing.
Already, LED grow lights produce excellent results, but the technology continues to advance, meaning that there are more innovations to come.
LED Lights FAQs
Here are some frequently asked questions regarding LED lighting for indoor growing.
What’s the Difference Between Full-spectrum and Targeted Spectrum LEDS?
Full-spectrum LED grow lights provide a balanced combination of red, blue, and other wavelengths that effectively mimic natural sunlight. This makes them suitable for all growth stages. Target spectrum LEDs are customizable, allowing you to adjust the light spectrum to meet the specific needs of your plant as it passes through each growth phase.
How do LED Grow Lights Affect Plant Nutrient Uptake?
LED grow lights enhance photosynthesis, resulting in a greater uptake of nutrients and greater plant growth.
Are There Plants That Don’t Respond Well to LED Lighting?
Plants can generally grow and thrive under LED lighting, but despite their versatility, there may be some plant species that don’t respond optimally to specific light spectrums or intensities. This makes it crucial to research the light requirements of your chosen plant species to select the LED grow light that matches their needs.
How Do LEDs Help in Reducing Plant Diseases and Pests?
LEDs can, in certain light spectra, enhance the plant’s natural defence mechanisms. This can make them more resilient to both pests and disease.
Can I Combine LED Lights with Other Types of Grow Lights?
LED lights can be combined with other types of light. This can result in a more comprehensive lighting system. You could, for example, use LED lights, which are relatively cool, with lighting that generates heat. The result will be a hybrid system that adapts to the plants need for different temperatures throughout the year.
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