Comparing Grow Light Technologies for Legal and Commercial Cannabis Cultivation|
Article - October 16, 2017 By LarsonElectronics.com
Comparing Grow Lights for Legal and Commercial Cannabis Cultivation
According to Forbes, legal cannabis sales reached a whopping $6.7 billion in 2016. New Frontier Data, a US-based market research firm, predicts the nascent industry to reach $24 billion by 2025.
The adoption of legal cannabis laws, by open-minded states, on medicinal and recreational levels, is currently driving this trend. To sustain growth in the industry, cannabis cultivators are turning to LED grow lights to optimize plant growth.
But it wasn’t always this way. Previously, growers preferred other lighting technologies – all of which are at risk of being superseded by LEDs.
Fluorescent vs LEDs
Initially, fluorescent lamps were widely used for indoor cannabis cultivation. This lighting technology offers accurate color rendering and clear, full-spectrum illumination (in a dual configuration – consisting of one warm bulb and one cool bulb). However, to mimic natural light, the luminary produces yellow and green, which are not very useful for plants. For specific wavelengths (more on this later), LEDs are more effective.
The way the two units produce light varies greatly. Fluorescent lamps rely on mercury and active gases for light output. These elements are considered to be toxic to humans. Hence, they are not designed for rough handling or for sustaining the creation of natural products for human consumption. Should a fragile tube shatter over a plant bed, the entire bed would have to be replaced to prevent contamination.
When it comes to energy consumption, fluorescent fixtures are considered to be efficient; but not compared to LEDs. The annual cost of running a nine-watt LED light at a rate of 16 hours per day is $5.09. An 80-watt fluorescent light equivalent costs $45.22 per year to operate at the same rate. Factoring in replacement costs, LEDs cost around 50 percent cheaper to adopt – at a rate of $37.29 per year (compared to $65.17 per year for fluorescent fixtures). The reason for this huge price difference is high maintenance costs for fluorescent lights, which is conducted more frequently due to its shorter lifespan.
Metal Halide and HPS
Traditional metal halide and HPS lamps are not viable options for cannabis lighting systems. The units waste a staggering amount of effort in converting energy to heat (instead of light). This is an issue for growers located in regions that experience extremely hot summer weather, like parts of California and Nevada – states with lax legal cannabis laws (California and Nevada fully legalized cannabis on medicinal and recreational levels). Turning on a set of metal halide or HPS lamps in an enclosed space will result in a spike in room temperature. Because of this, the luminaries are not useful for scaling operations, since deploying more metal halide or HPS lights in the space will generate more heat, requiring an increased effort in cooling the area down.
Although metal halide and HPS units are cheaper to acquire, in the long term, they are expensive to use and maintain. LEDs are known to be more costly to purchase; however, the lights end up costing less to use and maintain, from a long-term perspective. FarmedHere, the oldest indoor farm in the US, is a company that experienced the challenges of acquiring LEDs firsthand. In 2010, the business started off using fluorescent lamps. Recently, the company switched to LEDs, costing up to two times more expensive than the existing system. Megan Klein, president of FarmedHere, mentioned she did not think twice about making the big switch. Today, the business saves a whopping $45,000 a year on energy-related payments.
In addition to energy savings, LEDs offer up to three times longer lifespans than outdated technologies. With an average lifespan of 50,000+ hours, operators don’t have to replace the units as often. By comparison, metal halide fixtures come with an average lifespan of 15,000+ hours. The average lifespan of HPS lights also falls within that range at 18,000+ hours. After the expected lifespan of HPS lamps, the units start to consume more energy and decrease efficiency. Metal halide fixtures may start to perform erratically if issues related to the ballast arises. LEDs don’t utilize ballasts for operation and are not prone to the same issues.
Types of LED Grow Lights
LED grow lights vary, depending on the size of the operation, type of cannabis plants and preferences of the cultivator. For standard growing operations, linear (tube-style) LEDs can be used. These days, cannabis grow lamps don’t necessarily have to take on traditional “tube-style” form factors. Modern LED grow lights can be circular, square or rectangle. These units are mounted in a suspended configuration, close to the plants for direct exposure.
Portable grow lights are may also be used to supplement low sunlight levels for cannabis growing operations in hybrid greenhouses. These luminaries are mounted on carts for easy transportation around the grow site.
LED grow lights contain features that are uncommon in traditional grow fixtures. Some luminaries allow cultivators to select specific light bands for optimized growth. Red and blue are the recommended wavelengths for robust plant growth. However, it is vital to take into consideration that although red is the most effective out of the two bands, blue plays a critical role in regulating the entire process. Without blue light, cannabis plants would grow thin and long, which is very undesirable for consumers. Ideally, cultivators want dense and luscious characteristics, filled with trichomes (crystal-like hairs found on healthy cannabis buds, where potent elements of the plant exist).