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What to Look for in LED Grow Lighting

Adams Independent Testing reached out to Logical Green Solutions, an influential company in the indoor hemp growing industry, to see if they’d be willing to teach us about lighting. With more than 20 years of experience in lighting alone, we’re thrilled that they’ve agreed to share some of their wisdom with us! We hope you find their article below as interesting as we do.

What to Look for in LED Grow Lighting

Our goal today is to help your growing operation succeed by sharing knowledge to assist you from seed to sale. When growing hemp crop indoors, there’s a myriad of lighting options from which to choose. Do you use ceramic halide, high-pressure sodium (HPS), or light-emitting diode (LED)?
In our experience, LED is the most efficient, and we’ll explain why in more detail below. First, it’s essential to understand that there is a big difference between lighting for people and lighting for plants.

Lighting for Plants: What Are PPF and PAR Efficacy?

When determining plant lighting, you need to look at the light’s PPF (photosynthetic photon flux) and PAR (photosynthetically active radiation) efficacy. Knowing the PPF value of a light source allows for easy comparison of the total light output, which contributes to photosynthesis. The unit used to express PPF is micromoles per second (μmol/s).
PAR efficacy is the measurement of how much photosynthetic light your fixture produces per joule of energy used (μmol/J). We recommend energy-efficient lights with a higher PAR efficacy for indoor growing. When it comes to grow lighting, the higher the PAR efficacy (or μmol/J), the better.
Note: If a lighting fixture measures light levels in lumens, that’s the light humans see, not the light used by plants. It’s not a useful measurement of grow lighting. Occasionally, companies advertise light life with L70 reports, which depict how long it takes light emittance to drop down to 70%. It is important to note that photosynthetic light emittance starts to degrade at 90% of the lighting diodes power. The human eye, however, doesn’t notice light degradation until 70% (the reason for L70 reports).
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Which Lights Have the Highest PAR Efficacy?
Generally, we consider 1.5 umol/J efficient for plant photosynthesis and growth. Anything above 2.0 umol/J is very efficient. For comparison:
  • Many HPS fixtures on the market produce 1.3 umol/J or less
  • Some of the best HPS grow lights approach 1.7 umol/J
  • The best ceramic metal halide grow lights are just under 2.0 umol/J
  • LED grow lighting can go up to 2.5 umol/J
As you can see, LED grow lights are the most valuable for your growing operation and will help you maximize your harvest.

What Are LED Grow Lights?

The best LED grow lights are made specifically for growing hemp and high-THC cannabis. LED grow lights are far more energy-efficient when compared to standard halogen, fluorescent, or metal halide grow lighting. Unlike traditional grow lighting, you can tailor LED grow lights for the spectrums needed for each growth stage.
By controlling the spectrum of light that your cannabis and hemp plants receive, you can control the specific growth stage of your plants, increasing your yield.

How Are LED Grow Lights Used to Control Growth Stages?

When growing high-THC cannabis and hemp plants in natural sunlight, the time of year controls the plants’ growth stage. In spring and summer, for example, more blue light hits the earth. The light spectrum changes depending on the season, and tells the plants what to do (e.g., growth rate, flowering, budding, etc.). By using LED grow lights, you can control the spectrum of light that you expose the plant to at different points in its growth cycle. Therefore, you gain more control over when the plant grows, buds, and flowers.
As mentioned above, specific phases of the plants’ growth cycle require different spectrums of light. During the germination and flowering stage of the plants’ development, the plants benefit from more blue light. With additional blue light, the plant focuses its efforts on photosynthesis and accumulating resources for reproduction. When approaching the seeding phase, increasing the amount of red light promotes rapid growth and helps the hemp and cannabis plants produce seeds.

Other Benefits of LED Grow Lights

LED grow lights:
  • Last longer than conventional grow lights (over double the life!)
  • Use less energy than conventional grow lights (saving you money on your electric bill!)
  • Emit less heat than conventional grow lights (up to 90% less!) 
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How to Get Started with LED Grow Lights

It’s a good idea to enlist a trusted partner when you’re getting started with LED grow lights to help navigate the sometimes-rocky waters. For example, Logical Green Solutions ensures you receive the most competitive lighting products, controls, and setup, specifically designed to optimize your plant growth, harvest, and profit. We can also provide lighting calculations and layouts to ensure that your lights are at the ideal level for your grow and will not burn or over-/under-light the plants. Lastly, as a trusted lighting partner, we aren’t manufacturer-specific. Therefore, we can provide options and ensure you’re receiving factual information. Because we’ve witnessed false advertising in the past, we always recommend comparing manufacturer claims against their DesignLights Consortium (DLC) records.

Ready to Get Started?

At Logical Green Solutions, we’re here to help you along every step of the operation. With the following information, our team can determine the number of lights you require, the output of light needed, and how to set up your lighting:
  1. The specific product for which you are growing.
  2. The canopy size needed to achieve your goal.
  3. Your specific grow areas and their setup.
To get started, please give us a call at 262-547-1111 or send us an email. If you don’t have an existing growing operation, Logical Green Solutions can also partner with our sister company, Total Team Construction, to bring you a complete package and make your job much more manageable.

About Logical Green Solutions

Logical Green Solutions' goal is to help you and the hemp industry succeed. We are your one-stop-shop in the hemp/cannabis industry from seed to sales—providing solutions for new and existing grow facilities. Our team of experts will work with you to make your facility more efficient, your job a bit easier, and increase your profitability. Visit us at for more information on how we can help you succeed and be more profitable.
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