A Look at Full-Spectrum Lighting

Full spectrum LED grow lighting is a patented reality, simulating the sun while remaining efficient.

Cannabis growers continuously pursue technological advancements for a variety of reasons, including higher yields, increased profits, and meeting regulations. Advancements in the various types of lighting used during any or all growth phases are no different. But studies show LEDs are becoming the industry's shining star, with an average of nearly two-thirds of cannabis growers opting for this efficient means of solar mimicry during at least one phase of growth.

Choosing a Lighting for a Cannabis Grow

Several factors must be considered when considering what type of lighting to install in an indoor cannabis grow. Price is typically at the top of the list, followed by light spectrum and energy efficiency to round out the top three.

High-Pressure Sodium (HPS) lights have been long preferred since they are relatively inexpensive and produce massive amounts of light, specifically from the red-orange spectrum, benefitting the cannabis flowering stage. This also means that despite the relatively high PAR emission, the limited spectral light output at certain wavelengths can't be optimized in the same bulb for photosynthesis and photomorphogenesis. In addition, the yellowish light HPS creates can make it challenging to read plant health.

Due to the amount of light created, HPS also emits a great deal of heat which needs to be managed using additional cooling and ventilation, meaning increased overall operating costs. The combined necessary equipment uses mass amounts of energy resulting in higher expenditures and environmental damage.

Many growers generally find it beneficial to switch between MH and HPS lighting during the appropriate growth phases. Metal halide (MH) offers much of its light in the blue spectrum, which is beneficial for photosynthesis in the early vegetative stage. An extreme fire danger lies with a shorter lifespan than HPS lights and extreme degrees of heat created by the electrical arc inside the gaseous bulb. MH is one of the greatest causes of ignition in cannabis operation fires.

Fluorescent, or T5 bulbs, are rich in blue light and great for seedlings or cuttings. They are more energy efficient and do create less heat than HPS. This means that several types of bulbs are needed to simulate natural sunlight. Thin glass tubes are also susceptible to breakage, containing substances like mercury and argon, making them potentially hazardous when broken.

LED lighting's size, efficiency, and durability have won the majority in each phase of cannabis growth. Advancements in technology have greatly improved the manufacturing cost of LEDs over the last decade. Consuming less energy than other systems, the customizable light spectrum that LEDs offer makes them beneficial in all stages of cannabis growth, the majority of which feature heavy red and blue spectrum lighting, henceforth the pink and purple light seen by the human eye. Given optimal lighting during each propagation, vegetation and flowering phase allow for generally higher yields of a better-quality product.

What are full spectrum LEDs?

Full spectrum LEDs are meant to mimic while improving upon the sun itself. While the sun is the chief energy source required for photosynthesis, it is not perfect as it cannot be regularly controlled or regulated for plant-specific growth cycles. Plants also do not use the full spectrum of the sun. Taking this into account, the full spectrum LEDs have been designed to feature the more desirable wavelengths that plants require.

This system includes at least one of a first LED that includes a 4000k LED having a first light output, at least one of a second LED with a second light output in about an orange spectra, at least one of a third LED with a third light output in about a green/yellow spectra, and at least one of a fourth LED having a fourth light output in about a red spectra. Each of these outputs combines into an aggregate light output mimicking the sun at a relatively efficient input power of about 600-650 watts, as described in Spectrum King's patent #10238043.

Spectrum King's patent also discusses design features such as an enhanced cooling system including a heatsink, multiple heat dissipation fins, and heat transfer pipes, which draw heat away from the circuit board and heat generating LEDs. Heat is transferred via heatsink fins positioned for convection cooling within a vented heat sink housing.

All of this translates into the latest advancement in LEDs: truly full spectrum grow lighting, customizable for optimal lighting depending on the crop, as each cannabis strain has minute variables that differentiate themselves from one another.

Hesitations with Switching to LED

According to Cannabis Business Times 2021 report, of the approximately 33% of growers surveyed not currently using LEDs, 62% are going to or are considering LEDs in the next 12 months. Those excluding LEDs typically do so because of cost. Either the upfront investment is too much, there are challenges in securing funding or capital, or the ROI is too long. Other reasons included LEDs "do not fit our current racking/stacking/shelving systems" or "LEDs cost too much to operate on a regular basis" and "unproven technology" Each of these reasons were given by 13% of the participating growers who do not currently or plan to use LED lights.

How to reduce the cost of switching to LEDs

Check with the utility company. Many offer rebates for improving energy efficiency with DLC-listed fixtures. The DLC Horticultural Qualified Products List is the most extensive verified list of high-performing and energy-saving LED solutions worldwide. Most utility companies will only give rebates for DLC-listed products. Make sure to know state requirements. In some places, plans must be utility-approved, so check on local regulations.

Most states offer tax credits and other rebates for making energy-efficient changes. Make the change to LEDs as soon as the state makes the credits and rebates available, as they tend to be more generous at first, then reduce over time.

Buying quality industrial-grade LEDs in conjunction with these credits and rebates can bring costs down, similar to an HPS installation. Combining these factors with energy savings from reduced wattage, reduced heat management, and increased lamp longevity, the total cost of ownership is also reduced. And that means more green, and an improved bottom line.