LED lighting system helps vertical agriculture and greenhouse crops increase yield

New LEDs are developing rapidly and are gradually being used in households, commercial buildings and other market segments, such as greenhouses and vertical farms. The new type of LED has better and richer spectral characteristics, and is more efficient and lower in cost than earlier LEDs and traditional high-pressure sodium (HPS) light sources.

The application of the new LED in the gardening field is better than the traditional HPS lamp: low power consumption, low heat dissipation, and long service life. These characteristics have opened up new opportunities for the gardening market. The new LED can be close to plants, can control the light intensity and spectral characteristics, and optimize the growth conditions of plants. This has two advantages: one is that growers increase the plant density in the greenhouse by vertically stacking plants (called vertical agriculture). The second is that growers can optimize the light time and spectrum of the greenhouse to speed up plant growth. LED has become the light source of choice for horticultural lighting equipment, but LED also has certain limitations. It requires a control circuit to achieve stable lighting and optimal plant growth environment spectrum. The closed-loop control driven by the spectral sensor can solve these problems.

The value of plant growth lights

Many plants only grow in a specific area and time, which is related to the temperature and humidity requirements of the plants. Another important factor is the light source, which directly affects photosynthesis and thus affects plant growth.

For example, some studies have found that light with a wavelength of 680nm is crucial to the growth rate of tomatoes during germination, but has little effect after germination. During the growth period, 650nm light can improve the content of chlorophyll a. Therefore, each stage of plant growth (germination, growth and harvest) requires different wavelengths of light.

In the northern hemisphere, if you want to grow tomatoes all year round, you need a greenhouse. To protect tomatoes from the bad weather in winter, it is equipped with a lighting system to make up for the lack of natural light in winter, and to create an environment with the best spectral characteristics for its growth. Optimize the lighting solution so that the lighting system can reflect the daily changes of the solar spectrum and keep it consistent with the day and night cycle of plants.

Like tomatoes, other plants also need specific spectral characteristics to promote growth and photosynthesis. The spectral characteristic curve includes spectral wavelength range and illuminance. The main wavelength of the spectrum used for horticulture is visible light from 400nm to 700nm, with peaks in the red and blue range. However, all plants need a full spectrum for optimal growth, and the circadian rhythm depends on the lighting conditions where each plant originated.

Since there are differences between plants of the same kind, the quality of light will have a great impact on the growth and development of specific plants. Monitoring the intensity, spectrum and circadian rhythm of the light source can ensure the best light conditions.