Original Source: Houcheng Liu. Development status and trend of LED plant lighting industry[J].Journal of Illumination Engineering,2018,29(04):8-9.
Article Source: Material Once Deep

Light is the basic environmental factor of plant growth and development. Light not only supplies energy for plant growth through photosynthesis, but also is an important regulator of plant growth and development. Artificial light supplement or full artificial light irradiation can promote plant growth, increase yield, improve product shape, color, enhance functional components, and reduce the occurrence of diseases and pests. Today, I will share with you the development status and trend of plant lighting industry.
Artificial light source technology is more and more widely used in the field of plant lighting. LED has many advantages such as high light efficiency, low heat generation, small size, long life and many other advantages. It has obvious advantages in the field of grow lighting. Grow lighting industry will gradually adopt LED lighting fixtures for plant cultivation.

A.The development status of LED grow lighting industry 

1.LED package for grow lighting

In the field of grow lighting LED packaging, there are many kinds of packaging devices, and there is no unified measurement and evaluation standard system. Therefore, compared with domestic products, foreign manufacturers mainly focus on high-power, cob and module directions, taking into account the white light series of grow lighting, considering with plant growth characteristics and humanized lighting environment, have greater technical advantages in reliability, light efficiency, photosynthetic radiation characteristics of different plants in different growth cycles, including various types of high-power, medium power and low-power plants of different sizes products, to meet the needs of a variety of plants in different growth environments, expecting to achieve the goal of maximizing plant growth and energy saving.

A large number of core patents for chip epitaxial wafers are still in the hands of early leading companies such as Japan’s Nichia and American Career. Domestic chip manufacturers still lack patented products with market competitiveness. At the same time, many companies are also developing new technologies in the field of grow lighting packaging chips. For example, Osram’s thin film chip technology enables chips to be packaged closely together to create a large-area lighting surface. Based on this technology, a high-efficiency LED lighting system with a wavelength of 660nm can reduce 40% of the energy consumption in the cultivation area.

2. Grow lighting spectrum and devices
The spectrum of plant lighting is more complex and diverse. Different plants have large differences in the required spectra in different growth cycles and even in different growth environments. In order to meet these differentiated needs, there are currently the following schemes in the industry: ①Multiple monochromatic light combination schemes. The three most effective spectra for plant photosynthesis are mainly the spectrum with peaks at 450nm and 660nm, the 730nm band for inducing plant flowering, plus the green light of 525nm and the ultraviolet band below 380nm. Combine these kinds of spectra according to the different needs of plants to form the most suitable spectrum. ②Full spectrum scheme to achieve full coverage of plant demand spectrum. This type of spectrum corresponding to the SUNLIKE chip represented by Seoul Semiconductor and Samsung may not be the most efficient, but it is suitable for all plants, and the cost is much lower than that of monochromatic light combination solutions. ③Use full-spectrum white light as the mainstay, plus 660nm red light as combination scheme to improve the effectiveness of the spectrum. This scheme is more economical and practical.

Plant grow lighting monochromatic light LED chips(the main wavelengths are 450nm, 660nm, 730nm) packaging devices are covered by many domestic and foreign companies, while domestic products are more diverse and have more specifications, and foreign manufacturers’ products are more standardized. At the same time, in terms of photosynthetic photon flux , Light efficiency, etc, there is still a big gap between domestic and foreign packaging manufacturers. For plant lighting monochromatic light packaging devices, in addition to products with the main wavelength bands of 450nm, 660nm, and 730nm, many manufacturers are also developing new products in other wavelength bands to realize the complete coverage for photo-synthetically active radiation (PAR) wavelength (450-730nm).

Monochromatic LED plant growth lights are not suitable for the growth of all the plants. Therefore, the advantages of full-spectrum LEDs are highlighted. The full spectrum must first achieve full coverage of the full spectrum of visible light (400-700nm), and increase the performance of these two bands: blue-green light (470-510nm), deep red light (660-700nm). Use ordinary blue LED or ultraviolet LED chip with phosphor to achieve “full” spectrum, and its photosynthetic efficiency has its own high and low. Most manufacturers of plant lighting white LED packaging devices use Blue chip + phosphors to achieve full spectrum. In addition to the packaging mode of monochromatic light and blue light or ultraviolet chip plus phosphor to realize white light, plant lighting packaging devices also have a composite packaging mode that uses two or more wavelength chips, such as red ten blue/ultraviolet, RGB, RGBW . This packaging mode has great advantages in dimming.

In terms of narrow-wavelength LED products, most packaging suppliers can provide customers with various wavelength products in the 365-740nm band. Regarding the plant lighting spectrum converted by phosphors, most packaging manufacturers have a variety of spectrums for customers to choose from. Compared with 2016, its sales growth rate in 2017 has achieved a substantial increase. Among them, the growth rate of 660nm LED light source is concentrated in 20%-50%, and the sales growth rate of phosphor-converted plant LED light source reaches 50%-200 %, that is, the sales of phosphor-converted plant LED light sources are growing faster.

All packaging companies can provide 0.2-0.9 W and 1-3 W general packaging products. These light sources allow lighting manufacturers to have good flexibility in lighting design. In addition, some manufacturers also provide higher power integrated packaging products. At present, more than 80% of the shipments of most manufacturers are 0.2-0.9 W or 1-3 W. Among them, the shipments of leading international packaging companies are concentrated in 1-3 W, while the shipments of small and medium-sized packaging companies are concentrated in 0.2-0.9 W.

3.Fields of application of plant grow lighting

From the field of application, plant grow lighting fixtures are mainly used in greenhouse lighting, all-artificial lighting plant factories, plant tissue culture, outdoor farming field lighting, household vegetables and flower planting, and laboratory research.

①In solar greenhouses and multi-span greenhouses, the proportion of artificial light for supplementary lighting is still low, and metal halide lamps and high pressure sodium lamps are the main ones. The penetration rate of LED grow lighting systems is relatively low, but the growth rate starts to accelerate as the cost drops. The main reason is that users have long-term experience of using metal halide lamps and high-pressure sodium lamps, and the use of metal halide lamps and high-pressure sodium lamps can provide about 6% to 8% of the heat energy for the greenhouse while avoiding burns to plants. The LED grow lighting system did not provide specific and effective instructions and data support, which delayed its application in daylight and multi-span greenhouses. At present, small-scale demonstration applications are still the mainstay. As LED is a cold light source, it can be relatively close to the canopy of plants, resulting in less temperature impact. In daylight and multi-span greenhouses, LED grow lighting is more commonly used in inter-plant cultivation.

②Outdoor farming field application. The penetration and application of plant lighting in facility agriculture has been relatively slow, while the application of LED plant lighting systems (photoperiod control) for outdoor long-day crops with high economic value (such as dragon fruit) has achieved rapid development.

③Plant factories. Currently, the fastest and most widely used plant lighting system is the all-artificial light plant factory, which is divided into centralized multi-layer and distributed movable plant factories by category. The development of artificial light plant factories in China is very rapid. The main investment body of the centralized multi-layer all-artificial light plant factory is not traditional agricultural companies, but are more companies engaged in semiconductor and consumer electronic products, such as Zhongke San’an, Foxconn, Panasonic Suzhou, Jingdong, and also COFCO and Xi Cui and other new modern agricultural companies. In distributed and mobile plant factories, shipping containers (new containers or reconstruction of second-hand containers) are still used as standard carriers. The plant lighting systems of all artificial plants mostly use linear or flat-panel array lighting systems, and the number of planted varieties continues to expand. Various experimental light formula LED light sources have begun to be widely and widely used. The products on the market are mainly green leafy vegetables.

④Planting of households plants. LED can be used in household plant table lamps, household plant planting racks, household vegetable growing machines, etc.

⑤Cultivation of medicinal plants. The cultivation of medicinal plants involves plants such as Anoectochilus and Lithospermum. Products in these markets have higher economic value and are currently an industry with more plant lighting applications. In addition, the legalization of cannabis cultivation in North America and parts of Europe has promoted the application of LED grow lighting in the field of cannabis cultivation.

⑥Flowering lights. As an indispensable tool for adjusting the flowering time of flowers in the flower gardening industry, the earliest application of Flowering lights were incandescent lamps, followed by energy-saving fluorescent lamps. With the development of LED industrialization, more LED-type flowering lighting fixtures have gradually replaced traditional lamps.

⑦Plant tissue culture. Traditional tissue culture light sources are mainly white fluorescent lamps, which have low luminous efficiency and large heat generation. LEDs are more suitable for efficient, controllable and compact plant tissue culture due to their outstanding features such as low power consumption, low heat generation and long life. At present, white LED tubes are gradually replacing white fluorescent lamps.

4. Regional distribution of grow lighting companies

According to statistics, there are currently more than 300 grow lighting companies in my country, and grow lighting companies in the Pearl River Delta area account for more than 50%, and they are already in a major position. Grow lighting companies in the Yangtze River Delta account for about 30%, and it is still an important production area for grow lighting products. Traditional grow lamp companies are mainly distributed in the Yangtze River Delta, the Pearl River Delta and the Bohai Rim, of which the Yangtze River Delta accounts for 53%, and the Pearl River Delta and the Bohai Rim account for 24% and 22% respectively. The main distribution areas of LED grow lighting manufacturers are the Pearl River Delta (62%), the Yangtze River Delta (20%) and the Bohai Rim (12%).

B. Development trend of LED grow lighting industry

1. Specialization

LED grow lighting has the characteristics of adjustable spectrum and light intensity, low overall heat generation, and good waterproof performance, so it is suitable for grow lighting in various scenes. At the same time, changes in the natural environment and people’s pursuit of food quality have promoted the vigorous development of facility agriculture and grow factories, and led the LED grow lighting industry into a period of rapid development. In the future, LED grow lighting will play an important role in improving agricultural production efficiency, improving food safety, and improving the quality of fruits and vegetables. The LED light source for grow lighting will further develop with the gradual specialization of the industry and move in a more targeted direction.

2. High efficiency

The improvement of light efficiency and energy efficiency is the key to greatly reducing the operating costs of plant lighting. The use of LEDs to replace traditional lamps and the dynamic optimization and adjustment of the light environment according to the light formula requirements of the plants from the seedling stage to the harvest stage are the inevitable trends of refined agriculture in the future. In terms of improving yield, it can be cultivated in stages and regions combined with light formula according to the developmental characteristics of plants to improve the production efficiency and yield at each stage. In terms of improving quality, nutrition regulation and light regulation can be used to increase the content of nutrients and other health-care functional ingredients.

According to estimates, the current national demand for vegetable seedlings is 680 billion, while the production capacity of factory seedlings is less than 10%. The seedling industry has higher environmental requirements. The production season is mostly winter and spring. Natural light is weak and artificial supplementary light is needed. Plant grow lighting has a relatively high input and output and a high degree of acceptance of input. LED has unique advantages, because fruits and vegetables (tomatoes, cucumbers, melons, etc.) need to be grafted, and the specific spectrum of light supplementation under high humidity conditions can promote the healing of grafted seedlings. Greenhouse vegetable planting supplemental light can make up for the lack of natural light, improve plant photosynthetic efficiency, promote flowering and fruiting, increase yield, and improve product quality. LED grow lighting has a broad application prospects in vegetable seedlings and greenhouse production.

3. Intelligent

Plant grow lighting has a strong demand for real-time control of light quality and light quantity. With the improvement of intelligent control technology and the application of the Internet of Things, a variety of monochromatic spectrums and intelligent control systems can realize time control, light control, and according to the growth status of plants, timely adjustment of light quality and light output is bound to become the main trend in the future development of plant grow lighting technology.