As a term, “grow lighting” sounds interesting, and it is. Grow lighting enables plants to grow and thrive in indoor horticultural applications, such as indoor vertical farms, greenhouses, and controlled environment agriculture. Vertical farms are enabled by LED technology and have shelves of plants, stacked floor to ceiling, to vastly increase crop yields.
Until recently, high-pressure sodium (HPS) lighting was standard in indoor horticulture—then the LEDs came along. LEDs offer higher photosynthetic photon efficacy than HPS, choice of spectrum, reduced radiant heat, and the ability to turn off and on and dim quickly. LEDs were found to provide a 24-to-30-percent reduction in electricity consumption compared to HPS and other conventional horticultural lighting technologies.
Just what is the importance of indoor horticulture?
Traditional farming faces age-old challenges—soil degradation, groundwater depletion, and weather patterns made more dramatic by climate change. These days, American farmers are more likely than ever to have their crops destroyed by drought, flooding, or unexpected events like hurricanes. In addition, Americans are eating healthier these days, and indoor horticulture offers the best in organic growing.
However, even with higher efficiency LED lighting, indoor horticulture is highly energy intensive and has faced challenges since 2022 when energy prices spiked. Operators of indoor facilities are highly sensitive to the cost of electricity to run grow lights, and here, LED lighting steps to the forefront to provide the perfect answer. DOE research in 2020 indicated that if all indoor horticultural lighting at the time was converted to LED technology, annual horticultural lighting consumption would be reduced to 6.3 TWh of site electricity, or 60 tBtu of source energy, which represented lighting energy savings of 34 percent or $350 million. Perhaps the most interesting benefit of the use of LED technology in greenhouses and vertical farms is that they can be instantly controlled to respond to energy pricing, since plants can be relatively indifferent to the timing of their light dose.
The use of LEDs in horticulture benefits the lighting industry as well
The horticultural lighting application provides a new platform for LED lighting, encouraging lighting manufacturers to improve their products to meet the needs of the agricultural industry. For example, the direct relationship between plant growth and light level has caused lighting experts to rethink the reliability of LED products and their replacement cycle. The traditional way to measure LED lighting reliability is L70, meaning that when the LED degrades to 70 percent of its original output, the luminaire has reached the end of its useful life. But the horticultural market is far more demanding, and some LEDs used for this purpose are now listing a depreciation figure of L90—once the LED decreases to 90-percent output, it’s done. Horticultural lighting has also driven improvements in red LEDs, which are especially important to plant growth. The net result has been to improve and expand the LED lighting palette, improving the performance of the tunable luminaires that use these LEDs.
The LED and indoor farmers are a match made in heaven for America’s food system, economy, and for the lighting industry, which continues to explore the endless benefits of LED technology.