Monday, October 30, 2017

Photosynthesis is the process by which plants convert solar radiation into chemical energy. However, like the human eye, photosynthesis only utilizes a tiny fraction of the full electromagnetic spectrum emitted by the sun. This spectral range of Photosynthetically-Active Radiation (PAR) largely coincides with that of the visible spectrum of light and includes wavelengths from about 400 to 700 nanometers.

Plant cells contain light-absorbing molecules called pigments. There are three main pigments essential to photosynthesis, each of which only absorb specific wavelengths of light within the PAR spectrum: Chlorophyll a, Chlorophyll b, and Beta-Carotene. Each of these, more or less, absorb light wavelengths within the blue and red spectrums while reflecting greens and yellows. Because these photosynthetic pigments can only absorb and utilize these particular wavelengths of light, the specific use of red lights and blue lights within their respective spectral ranges is incredibly beneficial to a horticultural operation such as ours.

In the absence of natural sunlight, all of our lighting in the Grow Room is provided by 16 LED light boxes that allow us to carefully control the light spectrum and photoperiod in which our plants are grown. Each of these lights are set on timers and motorized tracks, which allows us to evenly control the duration of light exposure our plants receive. Each light box can be adjusted individually, and the proportions of red, blue, and white light they emit can be changed to meet our specific production needs by increasing or decreasing each color's intensity.

Generally speaking, the photoperiod and proportions of red, blue, and white light that should be used depend upon the stages of plant growth you wish to promote. For instance, compared to germinating seedlings, mature plants often benefit from a lower intensity of red light and higher intensities of blue and white. Some plants benefit from gradual increases in light exposure over the course of their growth, whereas others prefer their photoperiod to gradually diminish. Some plants can even be grown in continuous light exposure, 24 hours a day!

We use lighting conditions that are generally agreeable to most plant species because of the variety of plants we grow. Our plants are produced under 9-12 hours of light per day. Because we aim to extend and promote the vegetative growth of our mature plants, the intensities of red, blue, and white light our plants receive are as follows: 20% red, 80% blue, and 80% white. This is what gives the grow room its striking, purple glow! Our germinating seedlings are grown under full-spectrum fluorescent lamps (but research suggests that intensities of 40% red, 60% blue, and 60% white could also be used).

~ Tori 

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