3 min read

4 Types of Cannabis Lights: Pros vs. Cons


With so many types of horticultural lighting and even more manufacturers, choosing the right lighting fixture for your facility can be daunting and potentially leave you with more questions than answers. In this blog, 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 numerous commercial facilities and seen almost every variation of lighting configurations possible and provided some of the industry's top tips for growing cannabis with LEDs. At Agro Lighting, we focus on designing each model specifically tailored to its application. We believe that 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 into the most common types of lighting on the market and examine the pros and cons of each one.

Types of Cannabis Grow Lights


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


  • Less expensive.
  • Suitable for early stages of plant growth.
  • Relatively efficient.
  • Produce less heat than other lighting options.


  • Little to no canopy penetration.
  • Not suitable for vegetative or flowering stages.
  • Minimal yield per watt ratio.
  • It contains mercury known to be detrimental to the environment (bulbs must be disposed of according to federal regulations).


HID and HPS Lights for Cannabis

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


HPS (High-Pressure Sodium) Consists of a narrow "high pressure" arc tube supported inside of the bulb. The arc heats the mercury until the mercury vapor lights, putting off its signature orange hue. The sodium is the last material to vaporize inside the bulb.



  • Low initial cost
  • Good canopy penetration
  • Sufficient spectrum for flowering plants.


  • High maintenance cost
  • Very high heat emission
  • Low relative efficiency
  • Not practical for the vegetative stage
  • The yellow/orange hue makes it hard to identify deficiencies, toxicities, and pest issues.
  • It contains mercury known to be detrimental to the environment (bulbs must be disposed of according to federal regulations).


Metal Halide

MH or Metal Halide 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.



  • Low initial cost.
  • Ideal spectrum for the 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.
  • It contains mercury known to be detrimental to the environment (bulbs must be disposed of according to federal regulations).


LED (Light Emitting Diode)

LEDs produce light by passing an electric current through a semiconducting material (the diodes, which then emits photons through the principle of electroluminescence (a material casts light when power is applied to it). Many HID or HPS growers eventually make the switch to LED grow lights for cannabis due to their lifespan and longevity partnered with their energy-savings.



  • >50,000 hours (estimated lifespan).
  • Capable of the fine-tuning spectrum to optimize photosynthesis.
  • Minimal 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.


  • High initial investment.
  • *Light penetration varies between manufacturers.
  • *Spectrum and design vary between manufacturers.


In Conclusion

It’s easy to see why cultivators across the globe are making the switch to LED grow lights. The pros continuously outweigh the cons, especially in the ever-changing industry landscape. The Biden administration announced in April of 2022  two new rules that set stricter energy efficiency standards for light bulbs. The department projected the new rules would cut planet-warming carbon emissions by 222 million metric tons over the next 30 years, meaning cannabis cultivators would play a significant role in deducting carbon emissions. Opting for LEDs provides a more environmentally sustainable option for growers as lawmakers continue to phase out inefficient and damaging lighting options.


The Agro Lighting Design and Engineering Process

We approach every project as a unique challenge. All of our engagement processes begin with an analysis of your facilities, preferred grow methodology, and other specific goals and objectives. Using this information, we actively take part in the design and engineering process to create the optimal cultivation setup customized for you. We have worked with a diverse group of cultivation facilities who have had success in using various grow methods from hydroponics to full organics. This experience positions us as a leader in designing and implementing world-class agricultural lighting solutions. Talk to Agro Lighting today about marijuana cultivation consulting and discover the lighting options that help you grow more sustainably while saving money on electricity.


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