Here is some new information on a recent January 25, 2017 release of a Q1 2017 LED Grow Light technology “system” for marijuana: LED Grow Light Specification Sheet
The supporting LED Grow Light 2017 report includes testing as well as a section on Science Technology, Engineering, and Math (STEM): LED Grow Light Testing Report
People assume that Cannabis is the cash crop, but a new generation of LED grow light technology and vertical “rack” farming may prove that vegetables may also deliver very high yields per square foot of grow area. Vegetables grow faster than marijuana and they do not need as much vertical height, so indoor farmers can stack planting beds to extend the square footage of a warehouse. The advances in LED grow light technology for marijuana may have very positive impacts relative to sustainable indoor framing across the U.S. and around the world.
Background on LED Lighting for Agriculture:
An LED grow light will most often use less energy than traditional forms of illumination and include options for custom wavelengths, providing cost-effective opportunities for indoor farming. Controlled indoor farming also reduces the need for pesticides and provides geographic opportunities for farming that are not reliant on outdoor climate conditions and seasonality. These factors help increase the affordability of localized organic farming, in part by reducing the transportation distance from farm to table. LED grow light technology also has a lower operating temperature than traditional lights, so growers can place the LEDs closer to the plants than traditional lights without as much risk of burning the leaves.
Optimizing Light Distribution:
To date, farmers that choose to grow indoors have had choices from a range of different types of technologies. The majority of traditional grow lights, such as incandescent, high intensity discharge (HID), fluorescent, and induction, include light fixtures that distribute the light from a concentrated source such as light bulb fixtures or multi-tube fixtures. The lighting typically delivers a higher level of output directly underneath the fixtures with reductions in output as the horizontal distance from the centerline directly under the fixture increases. The light reduction creates uneven growth patterns given that perimeter plants receive less of the Photosynthetic Active Radiation (PAR) that is used for growth via photosynthesis. While the latest generation of LED technology offers energy-efficiency and customizable wavelengths to match the needs of particular plants at particular growth phases, to date LED grow light fixtures have presented the same challenge of concentrated light vs even distribution as previous forms of lighting technology. The adverse effects of concentrated light are increased as the fixtures are placed closer to the top canopy of the plants. As fixtures are mounted higher, the concentration of PAR is reduced, requiring higher output fixtures and added electricity cost. The technologies that include evenly spaced modules most likely have a higher likelihood of providing even light distribution.
Information on a linear module “system”: LED Grow Light System Information Page