The Effect of UV Light in Horticultural Lighting

What is UV light?

An ultraviolet ray is that part of the electromagnetic spectrum which falls between the visible light and X-rays. They are usually found within the 10 and 400  nanometer wavelength.
What are the different types of UV light?

Ultra-violet light for plants are grouped into three categories based on their wavelength, and they include:

• UV-A light (wavelength 320 -400nm): This UV light has the longest wavelength and is the least harmful, mainly used in products like nail lamps or UV flashlights.
• UV-B light (wavelength 290 – 320nm): This particular UV light causes cellular damage both in humans and plants. About 95 percent of this UV type is absorbed by the Ozone layer.
• UV-C light (wavelength 100 – 290nm): this UV light is extremely harmful and thankfully, absorbed by the earth’s atmosphere. UVC is the light used in sterilization processes, present in products like air purifiers or germicidal wands.

The  effect of UV light on Horticultural Lighting

The UV energy has an adaptation to the complete cycle of vegetative growth and consumption. And it is called "the belly of the seed" in the middle of growth. Seeds can benefit from UV energy in two ways. One is to strengthen the root system, and the other is to prevent or inhibit the seed mold.

For farmers, preventing seed mildew is still a benefit of ultraviolet energy, but there are many benefits. The ultraviolet energy can plant the shape, smell and taste of plants. In fact, UV energy can increase nutritional value and efficiency in plants like cannabis.
There are also secondary usages for ultraviolet light in agriculture, for example, it can be used to sterilize water plants that supply plants with water and nutrients. We are involved in such a vertical farming using shipping containers. UV irradiation also increases the shelf life of plants after harvest. It's good for both farmers and consumers. 

On the other hand, the advantages of tailored UV light for specific plants don't stop there. It is described UV as "the missing piece of the horticultural lighting puzzle" for its ability to provide stresses to the plants, which induce a favorable response — making more protective antioxidants to ward off disease as well as enhance the flavor, texture, and color of harvested produce. For example, various properties of cannabis can be affected by the appropriate application of UV light as a stressor, such as THC and terpene levels that deliver stronger plants with more medicinal value; or strawberries can be grown to be more vibrant in color and taste can be intensified as a result of the plant's natural chemistry changes.

Besides cannabis, vegetables, herbs, and lettuce benefit from UV-B, Edible plants have the same photoreceptor as cannabis. Nutrients like antioxidants and flavonoids (the things that make plants look, smell, and taste good) become more prevalent with UV-B exposure. There is also some interesting research showing benefits of UV-B post-harvest in extending the shelf life of produce and eradicating powdery mildew.

In conclusion

There is no doubt that at its core, ultraviolet light is helpful to crops, which it is a positive force in driving innovation for developing adaptive plants that can withstand harsher conditions, thereby ensuring food security for humanity.