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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!

    Make the Most of Your LEDs: 5 Tips for Cannabis LED Growing

    The growing prominence of LED grow lights in the cannabis community is undeniable. So we have put together a few tips for anyone wanting to give them a go.

    Contents:

    With LED technology rapidly advancing in recent years, more cannabis growers are now switching to LED for their indoor operations. Merely a novelty just a few years back, LED grow lights are now performing as well, if not better, than HID lamps, and have also become more affordable. Due to the many advantages of LEDs, from consuming less energy to being more robust and having a longer life span, they are now a great choice for indoor cultivators of different skill levels. If you grow cannabis with LEDs or plan to make the switch, here are some tips for you.

    WHAT TO LOOK FOR WHEN CHOOSING AN LED GROW LIGHT

    Before you go buying an LED grow light, it helps to know what’s available. Currently, there are three main types of LEDs that you can use to grow cannabis, each of which has its pros and cons. The type of LED light you should choose will depend on what exactly you’re looking for, and how much money you’re willing to spend.

    3 MAIN TYPES OF LED GROW LIGHTS

    • STANDARD (“PURPLE”) LED

    These standard LED light fixtures were the first type available for growing, and today, they’re still widely available. These lights contain a lot, sometimes hundreds, of small to medium wattage LEDs (3–5 watts per single LED) in a compact fixture. Cannabis growers sometimes refer to these as “purple” lights, as they often comprise a mix of red and blue LEDs that combine to emit a purple hue.

    The biggest advantage of these standard LED lights is their price point. Most are manufactured overseas, and you can find them aplenty on eBay and other places online. A disadvantage is that their quality is often lacking; they can be less than reliable, and their light output is often lower than other types of LEDs, leading to lower yields. To remedy this, we’re now seeing standard LEDs begin to include COB LED lights or UV LEDs in addition to the red and blue, which can help with yield and bud quality.

    These standard LED light fixtures were the first type available for growing, and today, they’re still widely available. These lights contain a lot, sometimes hundreds, of small to medium wattage LEDs (3–5 watts per single LED) in a compact fixture. Cannabis growers sometimes refer to these as “purple” lights, as they often comprise a mix of red and blue LEDs that combine to emit a purple hue. The biggest advantage of these standard LED lights is their price point. Most are manufactured overseas, and you can find them aplenty on eBay and other places online. A disadvantage is that their quality is often lacking; they can be less than reliable, and their light output is often lower than other types of LEDs, leading to lower yields. To remedy this, we’re now seeing standard LEDs begin to include COB LED lights or UV LEDs in addition to the red and blue, which can help with yield and bud quality.

    COB means “chip on board”. A COB LED is made of many hundreds of tiny LEDs on one single small chip, as opposed to differently coloured LEDs spread over the entire fixture (as is the case above). COBs are among the most efficient LEDs. They produce a very intense white light that is similar to the natural light spectrum of the sun. One advantage of COBs is that they have good penetration into the plant canopy due to their intensity, resulting in a final yield approaching that of quality HID lamps. They also have a light spectrum that is optimal for healthy growth, and are very energy-efficient.

    The drawback can be that a quality grow light with COB LEDs is quite expensive compared to cheaper purple lights. Some grow light manufacturers combine several COB LEDs into one fixture, often equipping them with lenses and reflectors. There are also lights available that are comprised of only one single COB. These single-COB fixtures can be a good choice for larger growing spaces, as you can space a number of them evenly for light distribution across the entire area. Most growers use COB LEDs with a light spectrum that works both for vegging and flowering, but you can also find those with a spectrum (“colour temperature”) tuned specifically to vegging or flowering.

    COB means “chip on board”. A COB LED is made of many hundreds of tiny LEDs on one single small chip, as opposed to differently coloured LEDs spread over the entire fixture (as is the case above). COBs are among the most efficient LEDs. They produce a very intense white light that is similar to the natural light spectrum of the sun. One advantage of COBs is that they have good penetration into the plant canopy due to their intensity, resulting in a final yield approaching that of quality HID lamps. They also have a light spectrum that is optimal for healthy growth, and are very energy-efficient. The drawback can be that a quality grow light with COB LEDs is quite expensive compared to cheaper purple lights. Some grow light manufacturers combine several COB LEDs into one fixture, often equipping them with lenses and reflectors. There are also lights available that are comprised of only one single COB. These single-COB fixtures can be a good choice for larger growing spaces, as you can space a number of them evenly for light distribution across the entire area. Most growers use COB LEDs with a light spectrum that works both for vegging and flowering, but you can also find those with a spectrum (“colour temperature”) tuned specifically to vegging or flowering.

    SPREAD-STYLE LED

    Spread-style LEDs are comprised of a large number of small LEDs that are spread out on a larger panel or board. There are also spider-style LEDs and rack-style LED lights, which are widely used in commercial greenhouses. The spider-style LED lights don’t use flat panels, but spider-like “arms” with LEDs instead.The main advantage of spread-style grow lights is that they are among the most energy-efficient LEDs, which means you can get the most light for the wattage you’re using. A disadvantage is that quality spread-style LEDs, such as the spider-style lights, can be extremely expensive.

    Spread-style LEDs are comprised of a large number of small LEDs that are spread out on a larger panel or board. There are also spider-style LEDs and rack-style LED lights, which are widely used in commercial greenhouses. The spider-style LED lights don’t use flat panels, but spider-like “arms” with LEDs instead. The main advantage of spread-style grow lights is that they are among the most energy-efficient LEDs, which means you can get the most light for the wattage you’re using. A disadvantage is that quality spread-style LEDs, such as the spider-style lights, can be extremely expensive.

    THE ADVANTAGES OF GROWING WITH LED LIGHTS

    We’ve already mentioned that LED lights have several advantages when compared to other types of grow lights, such as HID. Here is a full rundown of why you may want to choose LEDs for your next growing operation.

    1. LED LIGHTS ARE MORE ENERGY-EFFICIENT

    Compared to HID lights, LEDs are a lot more energy-efficient. They use less electricity, and will cost much less to operate in the long-run. Although high-end LED lights can sometimes cost a good chunk of money outright, the investment is almost always worth it as your savings over time will make up for the higher initial cost. Likewise, quality LED light fixtures will also have a longer life span compared to HID, the latter of which tends to lose performance over time and needs frequent replacement. A good LED light can last you many years with no maintenance needed.

    2. THEY RUN COOL

    LEDs produce a lot less heat compared to HID lights, which can be a big advantage as you won’t require extra cooling systems in your grow room or tent to keep temperatures optimal. This is especially advantageous if you grow in summer or happen to live in a warmer climate. The downside to this is that if you live somewhere cold, you may now need to consider a heater in the colder months. But as LEDs save you money over time, this can make up for the potential costs of running a heater.

    3. WITH LED, YOU CAN MOVE YOUR PLANTS CLOSER TO THE LIGHT

    LEDs produce less heat, which means less stress on your plants—so you can move your lights closer to your plants without any negative effects. Higher light intensity translates to higher yields!

    4. LED LIGHTS REDUCE YOUR WATERING SCHEDULE

    With less heat produced by lights, the soil in your pots will stay moist for longer, thus reducing the amount of times you need to water. If you’ve just switched from HID to LED and are used to your plants drinking quite a lot, you now need to be careful with your new watering schedule under LED, otherwise you might overwater your ladies.

    5. YOU NEED LESS NUTRIENTS

    When you water cannabis plants, you’ll normally do so with an infusion of nutrients. In addition to watering less, your plants will also need less nutes than they would before. In addition to some nice savings on nutrients, the less-frequent watering and feeding schedule will also decrease nutrient buildup, so there’s a lower risk of nutrient lockout and plant deficiencies.

    GROWING WITH LED: WHAT TO CONSIDER FOR EACH STAGE OF CULTIVATION

    As we touched on earlier, many types of LEDs have a fixed light spectrum that works for both the vegetative (growing) and flowering phases of cannabis. This way, you can just use the same light throughout your entire grow from seed until harvest.

    Although this is convenient for most, there are those who want to fine-tune their lights for best results and optimal efficiency in each growing phase. For this purpose, some commercial LED lights have a switch to activate a veg light spectrum or a flower light spectrum. Here are some more factors to consider throughout each stage of growth.

    A) LED LIGHTS AND SEEDLINGS

    As soon as your seeds have sprouted, your soon-to-be cannabis plant will need light to grow. Compared to more mature plants, however, your seedling is much more sensitive to intense light. Because of that, you should be careful when starting out with strong LEDs.

    If your LED has a dimming option, turn your light to a lower intensity. If this isn’t an option, consider moving your lights further up, away from the seedling. On the other hand, ensure that you do not move the lights too far up, as this could cause the seedling to grow spindly and lanky.

    Likewise, if your LED has a switch to activate either a vegging or flowering spectrum, set it to veg, where the light normally emits a “cooler” blueish light, which is optimal for this stage. Set your timer to 18 hours of light per day, with 6 hours of darkness.

    As your seedling grows taller, stronger, and approaches the most robust part of the vegetative growing stage, you can then gradually increase the light intensity.

    B) LED LIGHTS DURING VEGETATION

    Set your light to 18 hours per day and 6 hours of darkness. Some growers choose to grow with 20–24 hours of light to maximise vegetative growth.

    Monitor your plant’s development; if all goes well, it should grow healthy, strong, and bushy. If it grows lanky and spindly instead, this is likely because your plant is not getting enough light. Increase the intensity by lowering the light toward the plant canopy or turning up the intensity using the dimmer if your light has one.

    How long you want to veg your plant will normally depend on how much space you have available. You can technically let your plant grow under 18–24 hours of light as long as you want, but there will likely come a time when you want to switch to flowering, as the plant would otherwise simply grow too big. Know that some cannabis strains can stretch considerably (up to 2x or more) during early flowering. Take this into account upon deciding when to initiate the switch to bloom.

    C) LED LIGHTS FOR FLOWERING

    Photoperiodic cannabis starts to flower in late summer when the daylight hours naturally begin to diminish. Indoors, the grower is responsible for inducing bloom by setting the light schedule to 12 hours of light and 12 hours total darkness. If your LED light has a flowering switch, turn it to flowering mode.

    When you flower indoors on a 12-12 schedule, it is important that the 12 hours of darkness are not interrupted. So make sure that your tent or greenhouse doesn’t have any light coming in from outside. This would otherwise revert your flowering plant back to veg or potentially cause other issues such as hermaphroditism.

    If your LED has a dimmer, now is the time to turn your light to its maximum intensity, or lower your light to the recommended distance from your plants for the flowering stage. If you are not sure what this distance is, most grow light producers have recommendations available.

    Important: if you change anything with your lights, such as when you increase intensity and/or lower their position, make sure to do so gradually over several days, rather than in one go. Too sudden of a change can stress your plants too much.

    AUTOFLOWERS AND LED

    If you’re growing autoflowers rather than photoperiodic strains, you don’t need to bother with initiating flowering by switching your lights to 12 hours on/off. You can just leave your autoflowers at 18–24 hours of light per day up until harvest. Then again, if your LED light has a flowering switch, you should still use it once your autoflowering cannabis is in bloom. This will help increase yield.

    LED COMPARED TO HID GROW LIGHTS

    HID lights, such as MH/HPS grow lamps, are still widely used as they are cheaper than good LEDs, yet are still reliable for growing top-quality weed. Furthermore, grow tent kits often include HID lights, so many new growers start out with these, rather than LEDs. If you’re wondering now whether you should switch to LED, here are some more aspects to think about.

    WHAT IS YOUR BUDGET?

    Although you can get LED grow lights “for cheap” nowadays, many of these budget versions from overseas are not worth the money you’d save outright from avoiding high-quality fixtures. If you want quality LEDs, you will normally need to spend some good money to get a light that promises good yields and will last you a long time. So if you’re on a budget and don’t want to, or can’t, spend a lot, it makes sense to continue with HID for the time being, rather than settling for a cheap LED. HID lights will still do a splendid job supporting growth and flowering—in fact, they can still outshine a decent amount of LEDs when it comes to performance.

    HEAT PRODUCED BY HID LAMPS CAN BE A PRO OR CON

    As already mentioned, HID lamps produce a large amount of heat. So, if heat in your grow room is a concern, you definitely want to look into LEDs. This can save you additional money on exhaust and cooling systems. On the other hand, if you grow in a cold environment, you may just want to stick with your HIDs as they keep the grow room cosy for your plants without needing additional heating.

    WHICH LIGHT GROWS BETTER (AND MORE) BUDS?

    Are there any differences in bud quality and yield with LEDs compared to MH HID lights? Some growers say that MH lamps give better yields or “prettier buds” compared to LEDs. But there are also those who say that, although HID might give you better yields, LED lights make for a better taste and/or overall better quality of weed. Obviously, what is really “better” is open to interpretation.

    For additional information on how LEDs compare to other types of grow lights, you can also read our article on the pros and cons of different types of lights for cannabis.

    HOW TO AVOID PROBLEMS WHEN GROWING WITH LED

    Modern LED grow lights, for example COB lights, can emit light that is as intense as that from HID. If your plants are too close to your LEDs, this can lead to “light burn”, with discoloured or bleached leaves, nutrient deficiencies, and all sorts of growing troubles. Because of this, it is important to keep your LEDs the proper distance away from your cannabis plants.

    There is no “one size fits all” recommendation for the right distance for all types of LEDs, since this varies greatly by type. It depends on the amount of light your LED is emitting, whether your lamp also uses lenses or reflectors, and so on. The manufacturer of your lights should clue you in to the recommended lamp distance from the canopy, either on the instructions that come with your lights or on their website. As a general rule, however, most LEDs should be about 30–45cm away from the tops of your plants to support healthy and vigorous growth.

    Making the switch to LED grow lights can be as intimidating as it is exciting. Here are 5 tips all new LED growers should know.