What are FR (far-red light) and UV (ultraviolet light)? What are their uses for plants?
When discussing topics related to "plant cultivation methods", light, soil, water, temperature and humidity are all key factors. Among them, in terms of light, the most discussed are light intensity, light duration, and spectral red-blue ratio.
Like far-red light and ultraviolet light, they are often regarded as "marginal roles", but in fact, the impact they play may far exceed your expectations.
Today, let's take a look at what FR is, what UV is, and what impact they can have on plants.
What is FR?
FR stands for far-red light, which refers to light with a wavelength between 700 and 780 nanometers.
What is the effect of FR light on plants?
Let's first think about a question: How do plants know when to bloom and when to grow taller?
The answer lies in - phytochrome.
Phytochrome is a photosensitive protein in plants that is responsible for receiving light signals like a detective and telling plants how to act.
FR light is an important triggering factor.
It affects the flowering and fruiting of plants, as well as the growth of stems and leaves, by changing the phytochrome in plants, and can also control the morphology of plants.
For plants that rely on photoperiod regulation, such as cannabis, FR light can shorten their growth period, allowing them to enter the flowering stage faster and save planting time.
What is UV?
The right amount of ultraviolet light can enhance the resistance of plants, improve the color of the plant surface, and increase nutrition.
Compared with FR light, UV light (ultraviolet light) is mainly divided into three types: UVA, UVB and UVC. In plant cultivation, the most commonly used ultraviolet light is UVA (320-400nm) and UVB (280-320nm), and UVC is basically blocked by the ozone layer.
What is the use of UV for plants?
1.UV light can enhance the resistance of plants.
UVB in particular can stimulate plants to produce more secondary metabolites, such as antioxidants and flavonoids.
These substances help plants cope with environmental stress, such as UV radiation, pests and diseases, and harsh conditions such as drought. Simply put, UV light is like a "gym" for plants. Through its irradiation, plants become tougher and more tolerant.
2.UV light can enhance the color and nutritional value of plants.
For example, ultraviolet rays can promote the synthesis of certain chemical components in plants, such as anthocyanins, which not only makes the color of plants brighter, but also enhances the flavor of fruits and vegetables.
Benefits of combining FR and UV light
Although FR and UV light have different effects on plant growth, the combination of these two spectra can bring dual benefits. During the flowering and fruit development period of plants, the right amount of FR light can accelerate flowering and fruiting, while UV light can improve the quality of fruits or flowers. The combination of the two can bring growers higher yields and better quality products.
Plant growth light recommendation: 120W UV/FR Led supplementary light bar
There are 4 light bars with a total output of 120W, which are mainly used to supplement UV and FR when using 1600W LED plant lights for indoor planting.
The UV light (365nm-370nm) on the supplementary light bar can be used as a supplement to the growth lamp, which can induce a larger leaf area and promote light interception, thereby significantly increasing plant yields. Proper UV exposure to plants can also improve the nutritional quality of plants and stimulate plant biomass production through stress.