What Is LED Horticulture Lighting?

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What Is LED Horticulture Lighting?

If you’re considering an indoor garden or aiming to give your seedlings a jump start, LED horticulture lighting is the perfect solution. It allows growers to create optimal growing conditions throughout the year, regardless of external factors like harsh weather. This blog post aims to offer you a comprehensive understanding of LED horticulture lighting. Let’s get started!

What Is LED Horticulture Lighting?

What Is LED Horticulture Lighting?

LED horticulture lighting utilizes LED technology to emit electromagnetic radiation that stimulates various photoreceptors in plants. This stimulation is crucial for driving essential processes such as photosynthesis, photomorphogenesis, photoperiodism and phototropism. All plants, whether they produce flowers, fruits, or vegetables, need light, water, carbon dioxide, and nutrients to survive and grow. Light acts as a catalyst for plants, enabling the synthesis of carbohydrates through the chemical reaction of carbon dioxide and water, thus supporting plant growth.

Plants have evolved to perceive light as a signal, allowing them to adapt and respond to their environment both in the short and long term. To sustain metabolic processes, promote active growth, ensure plant quality, and achieve optimal yields, plants need sufficient light. As sunlight’s intensity and spectrum often fluctuate, artificial light sources are employed to meet the plants’ growth requirements. These sources can serve as supplementary lighting to natural sunlight or as the sole source for photomorphogenic and photosynthetic processes.

For professional LED horticulture lighting, the key to optimization lies in developing tailored lighting recipes that cater to the specific needs of different plants during each growth stage.

Light and Plant Growth

Light greatly influences plant growth. Autotrophs by nature, plants have adapted to use light for the process of photosynthesis. Water and carbon dioxide are converted during photosynthesis into complex carbohydrates like cellulose or glucose. These carbohydrates serve as the fundamental building blocks for various metabolic pathways within the plant. The extra carbohydrates are put to use for biomass production, which includes the growth of flowers, fruits, and elongated stems as well as larger leaves.

Photoreceptor Pigments

Chlorophyll is the primary photoreceptor responsible for capturing light energy during photosynthesis, although other types of antenna photoreceptors, like carotenoids, also contribute to this process. In addition to promoting photosynthesis, electromagnetic radiation at specific wavelengths serves as an informational source for plants, influencing photomorphogenesis (changes in plant morphology brought on by light), photoperiodism (response to the light-dark cycle), and phototropism (growth towards or away from light).

There are two primary types of chlorophylls: chlorophyll A and chlorophyll B. Chlorophyll A is responsible for approximately 75% of photosynthetic activity. It absorbs light most efficiently at 430 nm and 680 nm wavelengths. On the other hand, chlorophyll B acts as an accessory pigment, with absorption peaks at 460 nm and 640 nm. Its role is to collect energy and transfer it to chlorophyll A. Chlorophyll B does not independently contribute to the biosynthesis process. The 3:1 ratio of chlorophyll A to B in plants indicates that plants rely mostly on chlorophyll A for photosynthesis. While chlorophyll levels rise when exposed to red and blue light, chlorophylls reflect the bulk of green light (550 nm to 650 nm), which is why we see green leaves.

Carotenoids, such as beta-carotene and xanthophylls (zeaxanthin, violaxanthin, and lutein), are another group of pigments in plants. They strongly absorb light between 450 nm to 550 nm. Carotenoids have yellow to orange hues because they reflect or transmit light within the wavelength spectrum of approximately 550 nm to 650 nm. Apart from their contribution to photosynthesis, carotenoids play a protective role for chlorophylls by dissipating excess light energy as heat when the photosynthetic system becomes overloaded.

Non-photoreceptor Pigments

Plants also possess non-photoreceptor pigments such as anthocyanins and flavonoids. These pigments serve as a form of sunblock, protecting the plant from high-intensity blue (400-500 nm) or ultraviolet (300-400 nm) radiation. Their presence helps impede the production of superoxide under such conditions. Anthocyanins, flavonoids, and carotenoids found in plants are not only involved in light-related processes but also serve as bioactive antioxidants. They play a crucial role in quenching free radicals and eliminating compounds that may cause photobleaching and inhibit plant growth.

The process of photomorphogenesis is mediated by different photoreceptors, namely phytochromes, cryptochromes, and phototropins. Phytochromes exist in two isoforms, Pr (660 nm red) and Pfr (735 nm infrared), Cryptochromes, which absorb light in the 340–520 nm range, are important for blooming plants because they regulate the entrainment of circadian rhythms and limit the elongation of hypocotyls, a portion of the embryonic stem. Phototropins, on the other hand, are protein kinases localized in the plasma membrane that govern processes like phototropism (growth towards or away from light), chloroplast accumulation, stomatal aperture regulation, leaf flattening, and inhibition of leaf expansion.

the absorption of Chlorophyll, Carotenoids and Phytochrome

What Are the Benefits of LED Horticulture Lighting?

LED horticulture lighting offers several advantages over traditional methods of plant cultivation, such as sunlight and soil.

Enhanced Environmental Control

With LED horticulture lighting, you have greater control over the growing environment. In this way, you can cultivate plants indoors throughout the year, regardless of external weather conditions.

Energy Efficiency

Compared with other types of lighting, horticulture LEDs consume approximately 17% less energy, resulting in cost savings on your electricity bills.

Light and Darkness Regulation

LED horticulture lighting allows you to regulate the duration of light and darkness that your plants receive. This is crucial as plants require specific periods of darkness for optimal growth.

Accelerated Growth

Plants grown under horticulture LEDs tend to grow faster than those relying solely on natural light. This is because horticulture lighting provides the ideal light intensity and spectrum necessary for plant growth.

Bigger Plants

When using horticulture LEDs, plants have the potential to grow larger compared with those grown solely in natural light. The controlled lighting conditions provided by horticulture lighting contribute to bigger plants.

What Are the Drawbacks of LED Horticulture Lighting?

Undoubtedly, horticulture LEDs offer numerous advantages, however, the potential disadvantages cannot be ignored.

Setting up an LED horticulture light, along with additional equipment like hydroponics systems and grow tents, can be expensive. The upfront investment may deter some growers.

Effectively using horticulture lighting can involve a learning process. Determining the optimal lighting setup for your specific plants may require trial and error, as different plants have varying light requirements.

There are common issues associated with LED horticulture lighting, such as burnt leaves due to excessive light intensity, insufficient light leading to stunted growth, and the risk of mold growth in humid environments. Proper knowledge and precautions are necessary to mitigate these problems.

What Are the Typical LED Horticultural Lighting Applications?

The main LED horticultural lighting applications can be boiled down as follows:

Top Lighting

Top Lighting

Top lighting refers to the practice of illuminating plants from the ceiling level, commonly employed in greenhouses. This method optimizes the capture of photons in the upper canopy while reducing the density of fixtures. However, top lighting systems consume a significant amount of power to ensure an adequate supply of photosynthetically active photons reaches the plants across a distance.

Traditional light fixtures like high-pressure sodium (HPS) and metal halide (MH) lights emit a considerable amount of thermal energy, which can raise the temperature of the plants. Consequently, these fixtures must be mounted at a minimum distance above the plants to mitigate heat-related issues.

In contrast, LED luminaires typically do not offer a comparable high photon flux from a single luminaire. Instead, multiple LED luminaires with lower photon flux are distributed throughout the space. The photon flux per luminaire can vary vastly depending on the lighting setup.

Vertical Farming

Vertical Farming

In vertical farms, plant factories, or multi-layer cultivation setups, crops are grown in stacked layers, allowing for high-density cultivation in compact facilities with the help of controlled environment agriculture (CEA) technology. Since natural sunlight is not available in these setups, artificial light becomes the sole light source. Hence it’s also called sole-source lighting. The light fixtures are positioned right above and near the crops. In such systems, it is crucial to use “cold” light sources like LEDs to prevent the plants from being burned by excessive heat. Achieving uniform illumination is essential for consistent crop growth across the entire cultivation area.

Using artificial light in this manner provides growers with complete control over the timing, intensity, and spectral composition of the light. However, it requires a comprehensive light spectrum to ensure optimal plant growth. Additionally, in such lighting conditions, it is important to provide a white light impression for workers to accurately assess the quality of the plants.

For vertical farming, Mokolight LEDs are recommended due to their high uniformity, particularly in the blue light spectrum.

Inter Lighting (Intracanopy Lighting)

Inter Lighting

Similar to vertical farming, inter lighting also necessitates “cold” light sources to ensure the safe growth of plants. LED technology provides an ideal solution for inter lighting, where the light sources are positioned between the plants and their leaves. This arrangement helps reduce shading caused by top lighting, allowing for increased light penetration even to the lower leaves. Unlike hot HPS lights, the low temperatures of LEDs do not harm the plants. Inter lighting is commonly used as supplemental lighting in greenhouses alongside natural daylight.

For inter lighting, Mokolight LEDs are recommended due to their balanced combination of efficacy and uniformity in providing the necessary light.

Consumer LED Horticultural Lighting

Grow Bulbs

Grow Bulbs

The main objective of these bulbs is not necessarily to achieve rapid biomass growth but rather to support the maintenance and growth of plants in low-light indoor conditions. Additionally, a pleasant visual impression is often desired. To meet these requirements, various types of white LEDs with different converter mixes are employed.

Grow Boxes

Grow Boxes

Grow boxes cater to the growing trend of home cultivation, offering the ability to grow plants entirely under artificial light within controlled environments. This application allows growers to customize the spectrum and lighting conditions according to the specific plant need. A wide range of LEDs with varying wavelengths are utilized to create the optimal lighting recipe for the targeted product.

LED Horticulture Lighting Portfolio at Mokolight

LED Horticulture Lighting Portfolio at Mokolight

Mokolight places a significant emphasis on horticultural lighting due to its ability to provide favorable conditions for plant growth, even in challenging weather or dark winters. We acknowledge the importance of horticultural lighting and ensure that our horticulture LEDs are designed with adjustable spectrum and intensity. Furthermore, our LED lights adhere to international standards to guarantee quality and performance. For further information or support, please contact us.

Written by ——
Scott Hughes
Scott Hughes
Double Bachelor's degrees in Architecture and Electrical Engineering, 5+ years of experience with LED lighting, intelligent moving lights, and conventional fixtures. Reach Me Now>>
Scott Hughes
Scott Hughes
Double Bachelor's degrees in Architecture and Electrical Engineering, 5+ years of experience with LED lighting, intelligent moving lights, and conventional fixtures. Reach Me Now>>
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