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Which LED Grow Lights Work for Cannabis?

October 31, 2020 – LED grow light technology has been improving rapidly especially in the last 1-2 years. Although just about any LED grow light (even the worst ones) can grow good weed, some newer models developed specifically for cannabis are getting better yields, density, and plant growth rates than older and generic models. We are currently doing extensive testing between different LED grow lights to determine which are the “best”. Every grow light on this page gets great results (just look at the pictures to see what to expect) but I’d like to specifically point out certain LEDs where the newest models are beating expectations.

If you’re not sure which LED company to use, I highly recommend…

More detailed information coming soon!

Table of Contents

Introduction – LEDs on average yield 0.5 to 1g/watt (of actual power draw

  • Spread Style (Ex: Quantum Board, Rack, or Spider)
  • Traditional Panel
  • COB Style

Trusted LED Grow Light Companies for Growing Cannabis – These LED models have been tested and shown to work well for growing actual live marijuana plants

More About Growing with LEDs

Introduction: Are LEDs a Good Choice for Growing Cannabis?

LED grow lights are relatively new to the cannabis growing scene, but they have become wildly popular over the last few years with their ability to produce great yields while staying cool and using a reasonable amount of electricity.

Yields! With a quality LED grow light and an average-to-good grow, you can expect yields of about 0.5 to 1g/watt.

The final yield depends a lot on strain and grow skill, as well as the quality of the lamp itself, but that’s a good rule of thumb for most models. For example, a 200W LED (200W true power draw, not an “equivalent” wattage) would yield about 100-200 grams on average, or 3.5 to 7 ounces.

Today’s LED models are much better for growing cannabis than the ones available even a few years ago. Many modern lamps are full spectrum or “wideband” spectrum (instead of only red and blue light diodes, which product a bluish purple light and are sometimes called “blurples”). Full spectrum light is easier on the eyes and adding at least some amount of green light to blurples typically results in healthier growth. Other spectrum colors like red, far red, and infrared are important for the budding/flowering stage. LED manufacturers have developed specialized lenses to point light directly to the plants and increase penetration, resulting in bigger yields for the same amount of light compared to older models. There are also many different form factors, with everything from the casing to the size of the diodes varying from model to model.

Modern LED grow lights can produce impressive results. These cannabis plants were grown completely under LED grow lights from seed to harvest!

Pic by Joe “Nunyabiz” Nunya, an avid LED grower who uses ViparSpectra LEDs

3 Main Types of LED Grow Lights

There are 3 main types of LEDs that are most commonly used for growing cannabis. Each type of model has its pros and cons, so there isn’t yet a “best” LED type. Some are better for some situations than other.

1.) Spread Style

Many smaller LEDs are spread out over a large area. Examples of this style include Quantum Boards, Rack and “Spider style” LED grow lights.

Quantum Board

The name “Quantum Board LED grow light” originated from Horticulture Lighting Group, though the term is now sometimes used for any LED in this style. They tend to have relatively low wattage diodes which are spread out over a large area on a board. These are becoming more popular lately, and seem to offer particularly good results for the amount of wattage used.

Spider LED

The “spider style” LEDs are similar to Quantum Boards in that the individual diodes are spread out and tend to be on the smaller side, but they are set on a panel with “arms” like a spider as opposed to a solid board. One very popular example is the SPYDRx line of LED lights. These typically have an extremely high price, but growers who use them swear they get better results than any other type of LED grow light.

2.) Traditional Panel

The standard panel LEDs have small to medium wattage diodes and the lamps tend to be more compact. Most LED grow lights available today are in this style. They are sort of halfway between a Quantum Board and a COB Style light, with a mix of features from both.

I’m also seeing lots of new “hybrid” LED grow lights appearing, that contain a mix of big and little LEDs, and unique form factors that mix and match between all the styles.

3.) COB Style

These grow lights use huge COB (Chip on Board) LED “bulbs”. Each COB is incredibly bright and intense because they contain multiple LED chips in a small area. COBs produce more intense light than other types of LEDs, and each COB uses a significant amount of electricity. Cree is most popular brand of COBs.

Instead of having dozens of small diodes, COB style LED grow lights typically only have a handful of huge COBs, each with strong lenses to direct the light down into the plant. These are rapidly gaining in popularity and are known for having deep penetration into the plant canopy.

AutoCOBs

It’s also common to see LED grow lights that only have one COB per lamp. These make it easy to spread out your light over a grow area, one lamp at a time. Sometimes known as “AutoCOBs”.

Some LED grow lights have a single COB LED. Multiple units can be spread out as needed.

Each COB has its own spectrum, so you can create a custom spectrum for your plants by combining multiple AutoCOBs together. They are very configurable if you have an unusually shaped grow space, or want to be able to accommodate different plants of different sizes at the same time.

Some COB LED grow lights can be plugged into regular light sockets

Now that you have a basic understanding of the different types of LEDs, lets talk about using them for growing cannabis.

LEDs are often compared to HPS grow lights and each type of grow light has pros and cons for cannabis growers. Here’s the quick summary to help you decide whether LEDs are a good fit for you, and you can also read more deeply into the differences between LED and HPS here.

Choose LED grow lights if…

You want to use the most cutting-edge indoor cannabis grow lights with a customized spectrum of light

You are willing to do some research to determine the best LED grow light for your space (this article will help guide you)

You have some extra money to spend on your initial setup (some of the best LED grow lights have a high initial cost)

Quality (potency, smell, trichome development) and ease of use are important to you

Which LED grow light brands can be trusted?

This is a very short list, and is not in any way meant to be comprehensive. There are hundreds if not thousands of brands of LED grow lights, and a lot of them are great, but I’m only listing brands that I personally know for certain will work well for growing cannabis. These LED grow lights have actually been tested and given the seal of approval by real cannabis growers.

Get breakdowns of their best models for growing cannabis:

ViparSpectra LED Grow Lights

In our growing forum, many members have experimented with different grow lights for growing cannabis. Over the last few months, it has become apparent that one of the most popular brands for LED grow lights is an emerging company known as “ViparSpectra.”

I hadn’t heard of them until relatively recently (it seemingly started becoming very popular around late 2016 or early 2017).

Since growers are getting such great results with these lights, and they come at surprisingly reasonable prices for LED grow lights, I knew I needed to highlight this company as our most recommended LED grow light!

Example of a Cannabis Cola Grown Under ViparSpectra LED Grow Lights from Seed to Harvest – Buds Are Dense, High Quality and Potent

I will be adding moe pictures of real cannabis plants growing under these lights soon, to help you know what to expect. Keep checking back!

Breakdown of Different ViparSpectra LED Models:

Here is a breakdown of their different models. This list doesn’t include all their models, just the ones that seem to be performing the best. We omitted a few that just don’t seem as good as the others for some reason (as one example, the pro version of the 1200W seems to be getting some bad reviews based on its light footprint, despite the fact that all the other models in the series perform very well).

Recommended ViparSpectra Models:

  • “450W” – 200W actual wattage
  • “450W” (pro series) – 210W actual wattage pic by Joe “Nunyabiz” Nunya, an avid LED grower who uses ViparSpectra LED

The following marijuana plants were grown under Vipar Spectra LED grow lights

Cola produced by ViparSpectra LEDs

    Price: $120

Grow Space: 2.5×2.5’ coverage at 24” (suitable for vegetative stage) and 2×2’ coverage at 18” (suitable for flowering stage)

Actual Power Consumption: 200W

How Far to Keep from Plants: 24″ is the recommended starting distance from the plants.

Average Yields: 3.5-4+ ounces – keep in mind that the strain (genetics) and any plant training you do makes a huge difference in your final yields

ViparSpectra PAR450 (Dimmable, Pro Series)

    Price: $180

Grow Space: 2.5×2.5’ coverage at 32” (suitable for vegetative stage) and 2×2’ coverage at 24” (suitable for flowering stage)

Actual Power Consumption: 202W

How Far to Keep from Plants: 32″ is the recommended starting distance from the plants.

Average Yields: 3.5-5+ ounces – keep in mind that the strain (genetics) and any plant training you do makes a huge difference in your final yields.

Examples of buds grown under the ViparSpectra PAR 450 by “M”

    Price: $230

Grow Space: 2.5×2.5’ coverage at 34” (suitable for vegetative stage) and 2×2’ coverage at 26” (suitable for flowering stage)

Actual Power Consumption: 274W

How Far to Keep from Plants: 34″ is the recommended starting distance from the plants.

Average Yields: 4.5-6+ ounces – keep in mind that the strain (genetics) and any plant training you do makes a huge difference in your final yields.

This cola was produced under a ViparSpectra PAR600 LED grow light

These marijuana plants were grown under a ViparSpectra 600

ViparSpectra PAR700 (Dimmable, Pro Series)

    Price: $300

Grow Space: 2.5×2.5’ coverage at 36” (suitable for vegetative stage) and 2×2’ coverage at 28” (suitable for flowering stage)

Actual Power Consumption: 328W

How Far to Keep from Plants: 36″ is the recommended starting distance from the plants.

Average Yields: 5.5-8+ ounces – keep in mind that the strain (genetics) and any plant training you do makes a huge difference in your final yields. Some growers are getting even better yields with this light, it seems to be performing very well in tests.

    Price: $340

Grow Space: 4.5×4.5’ coverage at 32” (suitable for vegetative stage) and 3.5×3.5’ coverage at 24” (suitable for flowering stage)

Actual Power Consumption: 520W

How Far to Keep from Plants: 32″ is the recommended starting distance from the plants.

Average Yields: 9-14+ ounces – keep in mind that the strain (genetics) and any plant training you do makes a huge difference in your final yields.

Horticulture Lighting Group (HLG) LED Grow Lights

HLG first coined the term “Quantum Board” for an LED grow light with the diodes spread out over a large area (on a board). The board style LED grow lights have become very popular almost as soon as they appeared on the scene. Growers are reporting results that may beat even other LED grow lights when it comes to the amount of yield for the electricity used. I was impressed when I tried one myself. It’s probably too early to call it the winner just yet, but it’s undeniable these are some of the best LED grow lights available today!

Breakdown of Most Popular HLG LED Models:

HLG 65 V2 Quantum Board (all versions work well from seed to harvest)

    Price: $99

Grow Space: 2′ x 2′

Actual Power Consumption: 65W

How Far to Keep from Plants: 10-12″ away

Average Yields: 2-3+ ounces – keep in mind that the strain (genetics) and any plant training you do will make a huge difference in your final yields.

Here’s a Pineapple Chunk plant I’m growing under the HLG 65 (4000k version) right now. Look how big the buds are at only week 5 of flowering!

HLG 100 V2 Quantum Board (3000k version recommended from seed to harvest)

    Price: $149

Grow Space: 2’x2′

Actual Power Consumption: 95W

How Far to Keep from Plants: 12-14″ away

Average Yields: 3.5-5+ ounces – keep in mind that the strain (genetics) and any plant training you do will make a huge difference in your final yields. This LED model has performed better than most others I’ve tried so far.

Here are some plants I grew under the HLG 100 (3000k version)

    Price: $450

Grow Space: Up to 4′ x 4′ in the vegetative stage. It’s listed to cover between 2.5′ x 2.5′ to 3′ x 3′ in the flowering stage, but the rectangular shape actually makes it perfect for a 2’x4′ grow tent.

Actual Power Consumption: 270W at full power, and can be dimmed down to 90W for younger plants

How Far to Keep from Plants: 20-28″ for the vegetative stage. 18-20″ away in the flowering stage.

Average Yields: 8-16+ ounces – keep in mind that the strain (genetics) and any plant training you do will make a huge difference in your final yields. This LED model has performed better than most others I’ve tried so far.

I grew these cannabis plants under an HLG 300 V2 R-Spec LED grow light (view the grow journal). The 300L is the same light but longer (where the “L” comes from) to improve light coverage and they also added a spiffy red border.

Cannabis plants grown by depthchargeseeds under an HLG 300 Quantum Board LED grow light (check out their Instagram profile!)

HLG 550 Quantum Board (R-Spec spectrum recommended)

Price: $850

Grow Space: Up to 6′ x 6′ in the vegetative stage. Between 4′ x 4′ to 4.5′ x 4.5′ in the flowering stage.

Actual Power Consumption: 500W at full power, and can be dimmed down to 200W for younger plants

How Far to Keep from Plants: 20-28″ for the vegetative stage. 18-20″ away in the flowering stage.

Average Yields: 10-20+ ounces – keep in mind that the strain (genetics) and any plant training you do makes a huge difference in your final yields

Example of cannabis plants grown under the HLG550 LED Grow Light

Cannabis plants grown by cannabichiro under a HLG 550 LED grow light (check out their Instagram profile for more!) Cannabis plant in DWC grown by rumplenuggrower under a HLG 550 LED grow light (check out their Instagram profile for more!)

Electric Sky LED grow lights (The Green Sunshine Company)

This company makes “Quantum Board” or “Spread Style” LED grow lights. Normally I only recommend products that can be found consistently on Amazon.com, and sometimes these ones are available there, but typically you need to order directly from their website. However, I still included them on this list because the results are impressive. This particular company goes above and beyond as far as customer service and gives you detailed instructions on how to use their LEDs to get the best yields and results. The company supports cannabis growers and will answer questions about plants. They are constantly testing their lights and the results show it. As a result, I highly recommend this company for anyone looking for a high-quality LED.

Our plants growing under two Electric Sky 300 LED grow lights

Breakdown of Different Electric Sky LED Models:

    Price: $420

Grow Space: Between 1.5’x3′ to 2’x4′ grow space

Actual Power Consumption: 180W

How Far to Keep from Plants: 12-18″ away from tops of plants

Average Yields: 3-7+ ounces – keep in mind that the strain (genetics) and any plant training you do makes a huge difference in your final yields

ES180 found on Amazon (sometimes) or order directly The Green Sunshine Company website

    Price: $700

Grow Space: Up to 3’x5′ in the vegetative stage, 2’x4′ in the flowering stage

Actual Power Consumption: 300W at full power, dimmable

How Far to Keep from Plants: 36” away in vegetative stage, 18″ away in flowering

Average Yields: 5-11+ ounces – keep in mind that the strain (genetics) and any plant training you do makes a huge difference in your final yields

ES300 found on Amazon (sometimes) or order directly The Green Sunshine Company website

Picture of ES300 when turned on (unique spectrum is efficient for plant growth)

Six plants in a 4’x4′ grow tent, grown under two ES300 lamps

Here are those same plants at week 6 of flowering under the ES300 LEDs

Advanced Platinum LED Grow Lights

A relatively new name on the scene, Advanced Platinum is selling professional LED grow lights for less money than many other LED lamps of the same quality. Despite the cheaper price tag, they have a wider light spectrum than most LEDs, which helps plants grow faster with fewer of the leaf problems and deficiencies than you see with LED models that only have red and blue diodes. They’re making a good name for themselves in the cannabis growing community because their LED models are getting really great results when it comes to both quality and yields.

This company is known for great customer service and a 5-year warranty on all their lights.

Breakdown of Different Advanced Platinum LED Models:

    Price: $370

Grow Space: 2’x2.5′ or 2.5’x3′

Actual Power Consumption: 93W in veg, 185W in flowering (this model has a separate vegetative and flowering mode)

How Far to Keep from Plants: 24-38″ is the standard starting distance for the vegetative stage. You can move it to 18-20″ away in the flowering stage, or possibly even a few inches closer for light-loving strains.

Average Yields: 3+ ounces – keep in mind that the strain (genetics) and any plant training you do makes a huge difference in your final yields

    Price: $540

Grow Space: 2’x3′ or 3’x3.5′

Actual Power Consumption: 137W in veg, 255W in flowering (this model has a separate vegetative and flowering mode)

How Far to Keep from Plants: 24-38″ is the standard starting distance for the vegetative stage. You can move it to 18-20″ away in the flowering stage, or possibly even a few inches closer for light-loving strains.

Average Yields: 4+ ounces – keep in mind that the strain (genetics) and any plant training you do makes a huge difference in your final yields

    Price: $660

Grow Space: 3’x4′ or 3’x5′

Actual Power Consumption: 184W in veg, 368W in flowering (this model has a separate vegetative and flowering mode)

How Far to Keep from Plants: 24-38″ is the standard starting distance for the vegetative stage. You can move it to 18-20″ away in the flowering stage, or possibly even a few inches closer for light-loving strains.

Average Yields: 6+ ounces – keep in mind that the strain (genetics) and any plant training you do makes a huge difference in your final yields

Kind LED Grow Lights

Kind LED panels have recently been becoming very popular on the cannabis growing scene and seem to be getting great results especially when it comes to yields. However, they are definitely pricey even for LEDs, so that is a big consideration!

Breakdown of Different Kind LED Models:

While Kind LEDs offer several additional models of LED grow lights, because of the price tag on these lamps I’m only listing the ones I’ve seen used by actual cannabis growers, though I’m sure the other ones are likely just as good. That being said, the following models have been proven to work really well for growing cannabis!

Grow Space: 2.5’x3.5’’

Actual Power Consumption: 270W

How Far to Keep from Plants: The manufacturers of this Kind LED grow light recommend that the lamp be kept at least 36″ from the tops of your plants for the best results. This model is very, very powerful and keeping it too close will give your plants light burn!

Average Yields: 4+ ounces – keep in mind that the strain (genetics) and any plant training you do makes a huge difference in your final yields

Cannabis plants grown under the L450 Kind LED grow light

    Price: $600

Grow Space: 3’x4′

Actual Power Consumption: 320W

How Far to Keep from Plants: The manufacturers of this Kind LED grow light recommend that the lamp be kept at least 36″ from the tops of your plants for the best results. This model is very, very powerful and keeping it too close will give your plants light burn!

Average Yields: 5+ ounces – keep in mind that the strain (genetics) and any plant training you do makes a huge difference in your final yields

Cannabis plants grown under the L600 Kind LED grow light

pics by the very talented LED grower Laughing Buddha!

Are there other LED grow lights that work for growing cannabis?

There are certainly more LED grow lights out there which will probably work great for growing marijuana! But so far these are the only ones I’ve seen getting good results after being extensively tested on real, live cannabis plants. If you’ve got an LED grow light and would like to share information and pics about your cannabis grow (including final yields!), we’d love to hear from you!

As more LED grow lights appear on the market, we are testing LEDs and looking for other cannabis LED testers so we can share our knowledge!

You might be interested in…

LEDs vs Other Popular Cannabis Grow Lights

LEDs vs CFLs

LEDs get better yields for the same amount of electricity than CFLs. This is because LEDs are more electrically efficient (produce more light for the same amount of electricity)

Unlike CFLs, LEDs don’t need to be adjusted almost daily

LEDs give off less heat than a CFL setup with the same amount of electricity, and LEDs also come with additional cooling options like heatsinks and sometimes even built-in fans, which pushes all the heat up and away from the plants, making it easier for growers to maintain comfortable temperatures.

  • LEDs need to be kept much further away from plants than CFLs, which means that CFLs are better suited to short grow spaces without a lot of available height. LED grow lights generally need to be kept 12-18+” away from the tops of plants, while CFLs can be kept just a few inches away.
  • LEDs vs MH/HPS

    I’ve seen many growers choose to mix LEDs with their HPS bulbs. In fact, combining MH/HPS with a quality LED panel may be a great way to improve the quality of your harvested buds. There are lots of growers who claim that LEDs increase potency and density, as well as bring out the natural smell/taste of your strain. On the flip side, some growers believe that HPS tends to produce “prettier” buds.

    If you’re most concerned with improving your yields/watt, skip the LEDs and get an HPS grow light for your flowering stage. Although LEDs are catching up and there are some really great LEDs out there that get comparable results, HPS still tends to give you bigger yields when it comes to how much electricity is being used.

    LEDs can get pretty pricey, though not all brands! In fact, some great brands are actually some of the cheapest!

    Several growers believe LEDs produce higher quality buds (more trichomes, higher potency, and bring out the natural taste and smell of buds). They also tend to bring out colors.

    LED grow lights come with built-in cooling systems and heat sinks which vent air up and away from plants. This can make it so that you can hang the LED grow light in your tent and not necessarily need an exhaust system to control the temperature

    LEDs are plug-and-play which means you can plug them directly into a wall without a ballast

    What’s the difference between buds grown under LED grow lights compared to buds grown under an HPS grow light? Do the buds look/taste/smell different?

    Although this is just one example, this is pretty typical of LED grow lights in that they tend to bring out colors. This Eldorado plant was bloomed under two light sources, an HPS on one side and an LED on the other. Nothing scientific, no partitions, so there was light overlap. At harvest the color difference was surprising (see below) and after curing 2 select pieces from each side of the plant, the aromas are slightly different as well.

    View video of this Eldorado plant by Endive
    (check out Endive’s website)

    LED grow lights are a great choice for growers who are dealing with hot HPS lights and want to change to something that’s going to run cooler. Although LED grow lights do produce heat, the smaller models might not bring up the temperature of your grow space.

    Even the more powerful models of LED grow lights that produce a lot of heat still have built-in cooling systems to help prevent the heat from beaming directly down onto your plants.

    How to Use LED Grow Lights for Growing Cannabis

    With LED grow lights, you will generally get better results with many smaller LED panels, as opposed to a few big LED panels. For example, you will often get better results with 2 x 125W LEDs (total 250W) than you would with a single LED model that produces 250W. This is because more panels often make it easier for you to spread the light to where it’s needed.

    When it comes to growing cannabis, LED models with 3W chipsets (each individual bulb is 3W) seem to get some of the best yields/watt of all LED models without a lot of worry about light-burning your plants.

    With LEDs, always look at the “actual power draw” or “actual power consumption” which is the amount of electricity the LED panel actually pulls from the wall. When comparing different LED grow lights, this is the closest you get to a side-by-side comparison.

    Generally, your goal with LED panels should be 50-60 watts per square foot of grow space to get the best results.

    The most important thing to remember about choosing LED grow lights….

    Do Your Research!

    How to Avoid Problems with LEDs

    The most important thing to learn about your new LED grow light is the proper distance to keep it from your growing cannabis plants. The recommended distance varies greatly from LED model to model, but getting it right will make a huge positive difference in your results! So many growers unintentionally hurt their plants by keeping their LED grow light too close.

    Best Way to Avoid Problems with LED grow lights: Keep them the right distance away!

    If kept too close, LEDs may cause cannabis leaves to look discolored similar to a nutrient deficiency, even if nutrient levels are fine.

    This is especially common in the flowering/budding phase, especially towards the end of flowering when the same leaves have been directly under the LED for months. Discolored leaves don’t necessarily mean you’ve done anything wrong, especially if the LED grow light is being kept far enough away, but if you’re noticing it particularly near the lights, it’s a good indication it might be light burn. Most modern LED grow lights need to be kept at least 12-18″ away to prevent light burn.

    These leaf symptoms are caused by light burn (grow light too close), not a nutrient deficiency

    In addition to discolored leaves, too much light can also “bleach” the tops of buds

    There’s no “set” distance LED lights should be from the tops of your plants, but a good rule of thumb is 12-18+ inches.

    Each model is different based on the size of its bulbs and the lenses used to reflect light down. It’s important to ask the manufacturer how far to keep LEDs from your plants. Smaller LEDs with 1W chips almost always need to be kept at least 12″ away. However, most LEDs with 3W chips or bigger need to be kept 18″ away or more to get the best results and prevent light burn. Check with the manufacturer to figure out the right distance for your particular model of LED grow light. How can there be too much light if the heat is under control?

    If just the tops of your plants are showing symptoms, chances are that your LED lights are too close.

    Notice how the leaves closest to the light have turned completely yellow, while the leaves further down from the light are still green and healthy

    This plant was green and healthy through the vegetative stage under an LED grow light, but the leaves started dying soon after flowering started. It ended up that the LED was too close.

    These plants seem apparently healthy, but the top leaves keep getting lighter and lighter because the LED grow light was too close. If you don’t realize it’s light burn, the symptoms are inexplicable!

    LED grow lights need to be used properly to get the results, but if you know what to expect they pay you back with built-in cooling that allows a grower to hang their lights directly over their plants without worrying about fans, ducting or ballasts. They are easy on the electricity bill and don’t cause a lot of heat problems.

    Additionally, buds grown under LEDs are known for producing colorful, sticky, strong and smelly buds! And isn’t producing quality buds the reason we do it all?

    Learn how much heat, electricity and yields to expect with LED grow lights, and learn which LED companies test their lights on real cannabis plants!

    Can you grow pot with LED lights?

    Q. Dear Umbra,

    Can marijuana be grown as effectively under LED lighting and proper climate control rather than energy-sucking heat lamps?

    Cory W.
    Ann Arbor, Mich.

    Heavens, it’s a big week for pot questions. Why just the other day I answered a query about whether it’s safe to use plastic soil beads in potted plants, and now this. Thanks for keeping the theme alive.

    Marijuana aficionados stereotypically feel a deep and abiding connection with the natural world, or so I hear. So stereotypically, I’d expect it would harsh their mell to know what a whopping energy footprint their buds have. Pot may look like an oh-so-natural herb, but until recently the illegal nature of it has meant not much grew outdoors, kissed by sunlight and light breezes. Instead, as you note, most crops have been raised indoors, under enormously energy-intensive and inefficient lamps. The good news is there are indeed ways the indoor-weed industry can clean up its act, and LED bulbs are a big part of that.

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    But before we get to the solution, a look at the problem. Typically, growing operations use glaringly bright high-pressure sodium, or HPS, lights (metal halide and fluorescents are sometimes involved, too). How bright are we talking? Try 1,000 watts and 500 times brighter than your average reading lights. HPS lights are useful because they produce the wavelengths plants need to grow, but they do so quite inefficiently, and lots of the energy they tap ends up lost as heat. That means growers need to crank up the AC to keep their greenhouses the proper climate, further adding to their energy bills — and on top of that, many ops also use dehumidifiers and/or ventilation systems, and burn fossil fuels to boost the building’s carbon dioxide levels (a shot of CO2 makes plants, including pot, grow like — well, weeds). All told, producing the average joint creates roughly three pounds of carbon emissions, according to a 2011 study from the Lawrence Berkeley National Laboratory — equivalent to driving a hybrid car 22 miles.

    Might not sound like much, but all this adds up to staggering electricity bills for growers big and small. That Berkeley Lab study reported that the legal indoor marijuana industry accounts for one percent of the country’s power consumption; some larger growers blaze through $1 million worth in electricity every month. In Denver, which is ahead of the curve with pot infrastructure thanks to its trailblazing legalization of the stuff back in 2012, the marijuana biz uses closer to 2 percent of the city’s electricity, and growing. As more and more states (24 and counting) legalize recreational or medicinal marijuana use, we can expect this usage to increase.

    Unless, that is, the industry starts greening up its game. And research suggests that’s entirely possible: The Berkeley Lab estimates that upgrading to more efficient equipment and improving practices could reduce related energy use by 75 percent. And just like in our fixtures at home, switching to LEDs can make a huge difference. To find out more about how, I turned to Neil Yorio, technology advisor for a cannabis consulting firm in Denver and vice president of agricultural lighting research at BIOS Lighting. That company sells LEDs, but before his stint there, Yorio spent more than 20 years at NASA studying how to best raise plants on long-term space missions. The guy knows grow bulbs.

    LEDs are more efficient than HPS bulbs generally, and as Yorio pointed out: “With HPS, light comes out of 360 degrees from the lamp. Half the light is going in the wrong direction, to the reflector hood, and that decreases efficiency. With LEDs, all the light is going the direction you want it to.” What’s more, you can also engineer LEDs to produce only the kinds of wavelengths that plants need for photosynthesis. Boom, no more “spending money buying watts from the electric company to create light that the plants don’t use,” Yorio said.

    And then there’s the heat effect. Because LEDs run so much cooler than HPS bulbs, growers don’t need to blast the AC quite as aggressively to keep their plants happy. All together, Yorio estimates, LED grow bulbs will get the job done for half the energy. And yes, the herb they produce is just as good — and often, yields are higher, said Yorio. Sometimes, the light spectrums emitted by LEDs let farms raise even more potent puffs.

    LEDs are beginning to catch on in the industry, which is great news for the power grid. But even with these bulbs in use, “indoor cannabis production is an energy hog,” Yorio said. “Anything we can do to reduce energy consumption of the grid is something we should be embracing.” Like what, you may ask? Here’s one idea: System-wide measures like demand response, where the electric plant would coordinate with growers to shift their bright hours to off-peak times, therefore reducing pressure on the grid. And of course, switching over to renewable energy sources such as wind and solar would be better still. These next-level practices aren’t off the ground in a major way yet, but here’s hoping the weed industry will press these changes soon. Say what you will about pot and motivation — a million dollars up in smoke every month on an energy bill seems pretty darn motivational to me.

    Reefer madly,
    Umbra

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    With recent reports emphasizing the energy-sucking nature of the weed industry, a reader from Michigan wonders if LEDs could save the day.