Video published on Feb 28, 2017. Writer:Sam Lemonick. Narrator/Scientific Consultant: Darcy Gentleman, Ph.D.
If vertical farming is so great, why isn’t everyone adopting it? Vertical farming has its challenges.
By David Latchman
Open-field agriculture relies entirely on energy from the sun, so, when it is available, this source of energy is free. Crops grown indoors receive their energy from artificial light sources, which rely on electricity.
Another issue is that the artificial light sources, called grow lamps, emit heat, which can damage plants if they are placed too close to the plants. So the plants need to be spread out, and the indoor space needs to be cooled to compensate for the added heat from the lamps.
To address this particular challenge, vertical farmers are increasingly using another type of lamp, called a light-emitting diode (LED), which is a light source that is compact, energy-efficient, and can be designed to emit a particular wavelength (unlike a grow lamp, which emits light from the entire visible spectrum).
Plants do not use the entire spectrum of light. Research has shown that plants mainly absorb only portions of the light spectrum. Chlorophyll—a pigment that gives plants their green color—absorbs peak wavelengths around 450 nanometers and 650 nanometers (blue and red color, respectively) (Fig. 1). LEDs can be designed to emit only these wavelengths, so giving plants only the light they need—red and blue light—saves energy.