Return to Biophotochemical Applications


Plants are the main productive organisms on earth. They provide world’s oxygen supply and are a primary source of food for other living creatures including an ever- expanding human population. The light energy stored in plants not only allows the plants to grow, but also supplies the energy needed for every other living organism on earth.


Do plants grow faster under certain colors of light?

Plants, in fact, do grow faster under certain colors of light. The reason for this is that chloroplasts can only absorb certain wave lengths of light because of the pigments they contain. There are 2 photo systems in plants called photo system I and II. PS I absorb light on the wavelength of 700nm while PS II absorbs 680nm because of their utilization of chlorophyll A and B. These two frequencies are known as the peak absorption points because they are the wavelength at which light is most strongly absorbed. Different forms of chlorophyll and other photosynthetic pigments absorb other frequencies of light but PS I and PS II are what is used for synthesizing ATP and reducing power which plants use to grow. The visible spectrum of light is between 380-750nm for humans. Therefore PS I and II require red light to perform photosynthesis. As stated before, there are other photosynthetic pigments present in plants and other phototrophic species such as bacteria and algae that absorb other pigments. An example of this is the carotenoid pigment that absorbs primarily blue light as do chlorophyll A and B. Blue light contains more energy than red light but for PS I and II and plant growth are both needed. Studies in the 50’s showed that the rate of photosynthesis increased under far-red and red light compared to other frequencies.
Green plants will grow SLOWER or not at all under green light. Basically, green is the only brand of light that the plant’s chloroplasts don’t use. That is why it is the only colour reflected from the leaf, and is what we see.

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NASA scientists first utilized the power of LED (light emitting diode) photo light technology to spur plant growth on the Space Station. The lack of gravity in space keeps cells from growing naturally, resulting in slow-growing plant life.


Using LEDs in place of traditional lighting can reduce water use and often conserve up to 90% of electrical costs. Light quantity can be manipulated to achieve different plant growth patterns. For example this can be done by increasing light surrounding the plants with reflective materials, a white background, or supplemental lights. Blue and red light, which plants absorb, have the greatest effect on plant growth. Blue light is responsible primarily for vegetative (leaf) growth. Red light, when combined with blue light, encourages flowering.


A grow light or plant light is an artificial light source, generally an electric light, designed to stimulate plant growth by emitting an electromagnetic spectrum appropriate for photosynthesis. Grow lights are used in applications where there is either no naturally occurring light, or where supplemental light is required. For example, in the winter months when the available hours of daylight may be insufficient for the desired plant growth, grow lights are used to extend the amount of time the plants receive light.


Grow lights either attempt to provide a type of light spectrum similar to that or to provide a spectrum that is more tailored to the needs of the plants being cultivated.


Grow lights are used for indoor gardening, plant propagation and food production, including indoor hydroponics and aquatic plants. Although most grow lights are used on an industrial level, they can also be used in households.


Recent advancements in Light Emitting Diode LEDs allow production of relatively inexpensive, bright, and long-lasting grow lights that emit only the wavelengths of light corresponding to the absorption peaks of a plant’s typical photochemical processes. Compared to other types of grow lights, LEDs are attractive to indoor growers since they consume much less electrical power, do not require ballasts, and produce considerably less heat. This allows LEDs to be placed closer to the plant canopy than other lights. Also, plants transpire less, as a result of the reduction in heat, and thus the time between watering cycles is longer.


There are multiple absorption peaks for chlorophyll and carotenoids, and LED grow-lights may use one or more LED colors overlapping these peaks.


Our center designs and produces photo-array systems based on your requests and the location of plants growth.


The plants’ specific needs will be determinant on what lighting is most appropriate for optimum growth; artificial light must mimic the natural light to which the plant is best adapted. The bigger the plant gets the more light it requires; if there is not enough light, a plant will not grow, regardless of other conditions.