NITIN PURI#, SHUBHAM UPADHYAYA*, AKSHIT GOSWAMI^
#- Agriculture Analyst, FLUORTRONIX INNOVATION PVT. LTD.
*- R&D Engineer, FLUORTRONIX INNOVATION PVT. LTD.
^-Director, FLUORTRONIX INNOVATION PVT. LTD.
Artificial lighting, particularly through advanced LED grow lights, has significantly transformed horticulture by enhancing plant growth and productivity beyond the limitations of natural sunlight. This article explores the integration of artificial lighting with natural sunlight across various horticultural applications, including greenhouses, indoor farms, CEA, research in different molecular sectors and speed breeding programs. LED grow lighting addresses challenges such as variable natural light intensity, seasonal changes, and climatic conditions by providing consistent and optimized light conditions. LEDs grow offer precise control over critical lighting parameters such as PPFD, DLI, PPF, and light spectrum, which are essential for optimizing plant growth. The use of LEDs grow offers precise control over light intensity, spectrum, and duration, enabling targeted growth strategies for different plant stages and improving overall plant health and yield. This hybrid approach not only extends growing periods and enhances productivity but also contributes to energy efficiency and cost savings. In research, artificial lighting systems facilitate detailed studies of plant responses to diverse light conditions, advancing horticultural science and innovation. The article concludes that integrating artificial lighting with natural sunlight supports robust plant development, fosters sustainable agricultural practices, and benefits both growers and consumers.
Keywords- CEA-Controlled Environment Agriculture, PPFD-Photosynthetic Photon Flux Density, DLI-Daily Light Integral, PPF-Photosynthetic Photon Flux
In horticulture, achieving optimal plant growth and productivity involves more than just soil management and watering. Light—its intensity, duration, and spectrum—plays a crucial role in plant development and health. Integrating natural sunlight with artificial light sources, particularly LED grow lights, represents a sophisticated strategy to enhance growth across various protected cultivation practices, including greenhouses, indoor farming, controlled environment agriculture (CEA), and others.
Light is essential for photosynthesis in plants, providing energy for its growth and development. However, plants can absorb more sunlight than they can use, risking damage to crucial proteins. Sunlight spans a spectrum from 300 to 1000 nm, but only about 50% is usable as photosynthetically active radiation (PAR), ranging from 400 to 700 nm. Plants utilize pigments like chlorophyll a and b to capture and convert this light, with chlorophyll-a absorbing light at 662 nm and chlorophyll b at 642 nm, which are vital for photosynthesis and growth.
Historically, supplemental lighting in horticulture relied on general lighting technologies such as high-intensity discharge lamps, fluorescent lights, metal halides, and incandescent bulbs to control photoperiods and growth. The advent of LED grow lighting represents a significant advancement due to its ability to produce pure monochromatic light, allowing precise control and customization. LEDs grow are replacing traditional bulbs due to their efficiency and versatility, though they require careful calibration to meet the specific needs of plants.
Challenges such as unpredictable natural lighting, limited daylight during winter, and climate change can affect yields and crop reliability. Protected cultivation methods like greenhouses and controlled environments addresses these issues. In greenhouses, LED Grow lights can supplement insufficient sunlight, extend growing periods and enhance plant development. In indoor farms, grow lighting provides consistent, optimal conditions year-round.
LED Grow lighting is also crucial for accelerating plant development through techniques like speed breeding, where specific wavelengths and photoperiods are controlled. Additionally, tailored lighting can improve crop nutritional quality. By harmonizing LED grow lights, thereby increasing yields and providing benefits to farmers and consumers alike.
Combining natural and LED Grow lights in polyhouses optimizes the photoperiod, which is vital for plant growth. Extending this period with supplemental lighting enhances plant responses, improving processes like flowering and tuber formation. This results in more vigorous growth, accelerated maturation, and increased yields. By balancing natural and artificial light, growers can boost productivity, shorten production cycles, and improve profitability, while also enriching the nutritional value of crops for better consumer health.
Greenhouses effectively blend natural and controlled environments to optimize plant growth, balancing protection from external weather with ideal growing conditions. Natural sunlight serves as the primary light source; however, its intensity and duration can vary significantly due to seasonal changes, weather conditions, and geographical location. This variability can impact plant health and productivity, making the integration of artificial lighting crucial.
During the winter months or in regions with limited sunlight, LED grow lights become essential. They supplement natural light, ensuring that plants receive adequate PPFD levels (Intensity) for photosynthesis and preventing growth stagnation. Additionally, different growth stages of plants require specific light spectra. Seedlings thrive under blue light, which promotes vegetative growth, whereas flowering plants need more red light.
LED grow lights provide the precise spectrum and intensity needed for optimal seedling growth. Research has shown that specific light conditions can significantly enhance plant health and yield. For instance, a blue light intensity of 75 μmol m-2 s-1 with a blue-to-red ratio below 1.0 can prevent spindly growth and promote flowering in tomato seedlings 8. Similarly, a light intensity of 100 μmol·m−2·s−1 with a 9:1 red-to-blue ratio is ideal for growing cucumber seedlings 9. Using grow lights alongside natural light ensures that seedlings receive the full spectrum required for robust growth.
Moreover, combining natural and artificial light sources allows greenhouse operators to maximize light utilization throughout the day. LED grow lights can extend daylight hours, especially during early mornings or late evenings when natural light is insufficient thus extending the DLI (photoperiod) of the plant light resulting in accelerated growth and shorter grow cycles. This continuous light cycle supports healthy plant growth and enhances overall productivity, making the most of both natural and artificial lighting in greenhouse environments.
In plant science and horticultural innovation, accurate and controlled light conditions are crucial for understanding plant biology. Hybrid lighting systems, which combine natural sunlight with LED grow lights, are increasingly being used in research facilities to offer a more comprehensive view of how varying light conditions impact plant growth and development. These systems allow researchers to conduct detailed experimental studies by simulating a broad range of light spectra, intensities, and photoperiods. This versatility enables the observation of plant responses to different lighting conditions, providing valuable insights into plant physiology and growth patterns.
The integration of natural and LED Grow lights through hybrid systems enhances data accuracy by creating growing environments that closely mimic natural conditions. This realistic simulation results in more reliable data and a deeper understanding of how light interacts with plant development. Moreover, hybrid lighting systems contribute to innovative solutions by allowing researchers to customize light conditions to explore new methods for enhancing plant growth and productivity. This research fosters advancements in horticultural practices and the development of novel technologies and techniques.
Additionally, hybrid lighting systems are employed in in-vitro techniques to improve experimental outcomes. By optimizing light conditions in controlled environments, researchers can better study plant development at the cellular level and improve the efficacy of tissue culture and other in vitro methods. Overall, hybrid lighting systems represent a significant advancement in plant research, bridging natural and artificial light to drive forward horticultural science and innovation.
Indoor farms, operating in environments devoid of natural sunlight, rely predominantly on artificial lighting to meet plant growth needs. LED grow lights are central to these setups due to their ability to precisely control light intensity, spectrum, and duration. However, integrating natural sunlight, where available, can significantly enhance the efficiency and effectiveness of indoor farming operations. By creating a hybrid lighting system that combines LED grow lights with natural sunlight from windows or skylights, indoor farms can optimize their lighting strategy. This approach reduces the reliance on artificial lighting, thereby lowering energy consumption and costs. LED Grow lights can be adjusted to complement the natural sunlight, providing a comprehensive light spectrum that supports robust plant growth. This hybrid system not only broadens the range of light available to plants but also ensures that energy use is minimized.
Incorporating natural light with LED grow lights also enables more efficient energy management. The intensity of LED Grow lights can be reduced or fine-tuned according to the amount of natural light available, leading to substantial savings on electricity while still fulfilling the plants' light requirements. Furthermore, LED grow lights can be programmed to simulate natural light cycles, including dawn, daylight, and dusk, even when natural light is present. This ensures a consistent and balanced light environment crucial for plant growth and development. By leveraging both natural and artificial light sources, indoor farms can achieve enhanced growth outcomes and greater operational efficiency.
In Controlled Environment Agriculture (CEA), the integration of artificial lighting, particularly LED grow lights, with natural sunlight revolutionizes plant cultivation by offering precise control over the growing environment. The ability to tailor light spectra through LED Grow technology allows for customization that meets the specific needs of plants at various growth stages. For instance, early-stage seedlings thrive under a higher proportion of blue light, which promotes robust development, while mature plants benefit from a mix of red and far-red light that supports flowering and fruiting.
To achieve optimal light distribution, natural sunlight can be channeled into the growing area using reflective panels or light tubes, while LED grow lights supplement this with additional illumination. This hybrid approach ensures even light coverage, minimizes shadowing, and fosters uniform plant growth. By fine-tuning light spectra and distribution, growers can enhance photosynthesis, leading to accelerated growth rates, quicker harvests, and increased overall productivity. The strategic combination of artificial and natural light in CEA systems thus maximizes plant health and efficiency, demonstrating a significant advancement in agricultural practices.
Speed breeding represents a revolutionary approach to rapidly develop new plant varieties by significantly shortening growth cycles. This method leverages advanced lighting techniques to enhance plant development, with hybrid lighting—combining natural sunlight and LED grow lights—playing a pivotal role. Extended photoperiods (DLI) are a key component of speed breeding, where LED grow lights simulate longer daylight hours, complementing natural sunlight to provide consistent and intense illumination post the sunshine hours. This strategy enables plants to work longer thus promoting accelerated growth and plants to mature more quickly.
Uniform light conditions are crucial for achieving reliable results in speed breeding. By integrating LED grow lights with natural sunlight, growers create a controlled environment that minimizes light variability, ensuring all plants receive equal exposure. This consistency is essential for accurately evaluating plant performance and breeding outcomes. For example, using systems like IN RICE-Speed Flower, one generation can be achieved within 58–71 days, resulting in 5.1–6.3 generations per year across 12 sub-groups10th . Another result state that, this approach has successfully harvested fully matured rice seeds just 97 days after sowing, highlighting the efficiency of the hybrid lighting strategy in accelerating both growth and development 11th. This optimized light environment not only reduces the time to harvest but also enhances the efficiency of developing new plant varieties, offering significant benefits for both researchers and commercial growers.
In modern horticulture, precise light management is crucial for optimizing plant growth. Natural sunlight, though broad-spectrum, is inconsistent due to seasonal and geographic variations. Hybrid lighting systems that combine natural light with targeted artificial LEDs offer a solution. Different wavelengths serve specific roles: red light (660-670 nm) boosts flowering and fruiting, blue light (450-460 nm) enhances vegetative growth and stem strength, and infrared light (730-740 nm) aids stress reduction and root development 12th
A targeted wavelength approach can be far more economical and can be implemented in a fraction of CapEx and OpEx cost compared to full spectrum implementation for the entire greenhouse. This brings a significant increase in quantity and quality of produce with minimal investment in LED grow lights setup.
Combining wavelengths can further improve plant performance. For instance, higher red-light proportions can increase yields, while higher green light levels boost phenolic, flavonoid, and vitamin C accumulation. In practice, a successful LED Grow Lights combination for lettuce cultivation in hydroponic systems has been 72% red, 10% green, and 18% blue13. Additionally, small doses of UV light can be beneficial, as they help eliminate disease vectors and enhance plant health. Integrating these targeted light wavelengths with natural light enables growers to maximize plant health, productivity, and efficiency across various cultivation environments.
Read more about how different wavelength can boost the plant growth.