Choosing The Right Light For Your Commercial Cannabis Operation: Part 1

With so many types of horticultural lighting and even more manufacturers, trying to choose the right lighting fixture for your facility can be a daunting task and potentially leave you with more questions than answers. In this article we will go through some of the most popular types of lighting and highlight the pros and cons of each one. Over the years we've visited countless commercial facilities and have seen pretty much every variation of lighting configurations possible. At Agro Lighting, we focus on designing each model to be specifically tailored to its application. We believe that in order to ensure success, you must look at your environment holistically. Choosing the right light is just one part of that process.

Let's first dive in to the most common types of lighting on the market and take a look at the pros and cons of each one.

Fluorescents: Work by ionizing mercury vapor, causing it to emit photons at UV frequencies. The UV light created is then converted into visible light by a phosphor coating on the inside of the tube.

Pros:

-Less expensive

-Suitable for early stages of plant growth

-Relatively efficient

-Produce less heat than other lighting options.

Cons:

-Little to no canopy penetration

-Not suitable for vegetative or flowering stages

-Minimal yield per watt ratio

-Contains mercury which is known to be detrimental to the environment (bulbs must be disposed of according to federal regulations).

HID (High Intensity Discharge): Consist of two main types of lighting, HPS (High Pressure Sodium) and MH (Metal Halide).

HPS: Consists of a narrow "high pressure" arc tube supported inside of the bulb. The arc then heats up the mercury until the mercury vapor lights, putting off its signature orange hue. The sodium is the last material to vaporize inside the bulb.

Pros:

-Low initial cost

-Good canopy penetration

-Sufficient spectrum for flowering plants.

Cons:

-High maintenance cost

-Very high heat emission

-Low relative efficiency

-Not effective for the vegetative stage

-Yellow/orange hue makes it hard to identify deficiencies, toxicities, and pest issues

-Contains mercury which is known to be detrimental to the environment (bulbs must be disposed of according to federal regulations).

MH: Features one electrode on each side of the inner arc tube. The electrodes pass an electrical arc through a mix of mercury and metal halide gasses, creating photons. Metal halides are compounds of metals containing Bromine or Iodine.

Pros:

-Low initial cost

-Ideal spectrum for vegetative stage

-Operates well in extreme temperatures (hot or cold)

-Good canopy penetration.

Cons: High maintenance cost

-Loses efficiency when not being run at full power

-Longer warm up and cool down periods

-Loses intensity over time

-Light uniformity reduces over time

-Contains mercury which is known to be detrimental to the environment (bulbs must be disposed of according to federal regulations).

LED (Light Emitting Diode): Produces light by passing an electric current through a semiconducting material (the diode), which then emits photons through the principle of electroluminescence (a material casts light when power is applied to it).

Pros:

->50,000 hours (estimated lifespan)

-Capable of fine tuning spectrum to optimize photosynthesis

-Very little heat emission, high relative efficiency

-Optimal light distribution

-Allows for multi-tier cultivation

-Little to no maintenance cost

-Can be eligible for state and federal energy rebate programs.

Cons:

-High initial investment

-*Light penetration varies between manufacturers

-*Spectrum and design varies between manufacturer.

*Due to the wide range of diode qualities and variances in spectrum and design, not every LED fixture is equally effective for cultivation.

Stay tuned for Part 2 of "Choosing The Right Light For Your Commercial Cannabis Operation" where we'll talk about what we believe to be the best lighting option for commercial cannabis operations and explain why.

-Nate Tilley, Senior Cultivation Specialist

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