Using LED grow lights to maximize cannabis yields (2023)

Selection; a wonderful freedom or a terrible burden? Choosing how to set up your cannabis grow involves many decisions, especially when it comes to lighting. Find out everything about LED lights, the different types, the best application and much more in our guide.

Lights are perhaps the most important piece of equipment for an indoor cannabis grow and can mean the difference between a massive yield from the best buds and a slightly below average yield.popcorn flowers. SoChoosing the right grow lightsis essential. But with so many out there, where do you start?

LEDs have come a long way in the last few years and could be on the way to becoming the best option for cannabis growers. However, there are a few things you should know about them before you go. LEDs are incredibly versatile, which is their greatest strength. But you can also come across LED lights that aren't good for your cannabis plants. So take a look at the following information before you buy LEDs to equip your cannabis grow.

What are LED grow lights and why should you use them?

Using LED grow lights to maximize cannabis yields (1)

LED stands for "Light Emitting Diode". It's an incredibly energy efficient type of lighting, capable of emitting very bright light at low temperatures for potentially years to come.

Because of the small size of each diode and the versatility of the technology, LEDs can serve many, many functions. From Christmas tree lights to street lights to full-spectrum grow lights, they become the obvious choice.

Some advantages of LED Grow Lights are:

  • cheap to run
  • great for running
  • Completelylight spectrum
  • Adjustable spectra: one light for the entire crop
  • Potentially promotes further trichome development
  • Saves water (due to less evaporation)
  • Due to the lack of heat, you can place them closer to the cannabis plants, increasing the exposure to light.

Some disadvantages of LEDs are:

  • Poor quality LEDs do not produce a suitable light spectrum for cannabis plants
  • It's hard to tell if a manufacturer is really doing well
  • The lack of heating can be a disadvantage in winter
  • Anecdotal evidence suggests that LEDs can stop autoflowering plants mid-flowering (more on that later).

However, given the recent developments in LED lighting, this is a very good choice if you're willing to do some research and invest in a good oneIndoor marijuana cultivation.

Which LED grow light should I buy?

Using LED grow lights to maximize cannabis yields (2)

Purchasing the right type of LED grow light will ensure that you are able to provide a sparkling runbuds covered in trichomes. You need to know the wattage and light spectrum to make an informed decision. Animals tend to respond to lumens: the brightness of light. Plants, on the other hand, respond to light frequency, so it's important to check the stats. A super bright light with the wrong frequency won't hurt you.

(Video) Maximize your Weed Yields with the same Grow Light | Lux & Par Meters

Different Types of LED Grow Lights

There are three main types of LED lights, each with their own advantages and disadvantages. If you are serious about your cannabis cultivation, higher quality models will produce significantly better results. And since LEDs last for years, if you want to keep growing in the future, invest in a good one now.

Violette Standard-LED

Using LED grow lights to maximize cannabis yields (3)

These are the original LED grow lights and come with a mix of red and blue diodes which together emit a purple light. Blue light helps the plant in the early stages of its life; the red in the latter. Some lights emit the same hue throughout the grow, while others have settings for bothvegetativejflowering stages.

This is the cheapest LED option, but it may also be the worst. Mass manufacturing affects reliability and it can be difficult to know if the light spectrum is within required frequencies.


Using LED grow lights to maximize cannabis yields (4)

COB lights are one of the highest quality LED options available and, unsurprisingly, one of the most expensive. COB stands for "Chip on Board" and consists of many very small LEDs that together emit a bright white light.

This intense light penetrates well into the canopy and provides your plants with a full spectrum of light. While some come with both veg and bloom settings, most only have one setting, which is enough for the entire grow.

These can be combined in large clusters, making them suitable for larger grow spaces.

Enhanced style LED

Using LED grow lights to maximize cannabis yields (5)

These use a large number of small LEDs arranged on a circuit board. They are extremely energy efficient and offer your plants a great light spectrum and light intensity. Commercial cannabis growers tend to use this option.

Variations such as spider styles are also available. These have long arms that go down so you can adapt them to your grow for optimal lighting.


Not surprisingly, these tend to be the most expensive option.

Related articleNeed side lighting for cannabis plants?

What size LED grow light do I need?

The size or power of the LED should be proportional to the size of your grow. For a one square meter crop, a light of around 400-600w would be ideal. As a general rule in the growing world, 1 watt of light typically equates to between 0.5 and 1 gram of cannabis at harvest time. This depends on a lot more than just light, but it's a good way to determine how many watts to use.

LED grow lights with a Veg/Bloom switch

As mentioned earlier, many LED lights have a switch to switch from the veg phase to the flowering phase. This changes the spectrum from blue (vegetable) to red (flower), reflecting the sun's frequency at different times of the year. It's not entirely clear if this is any better than a grow light that puts out full spectrum all the time, but it will likely draw less power by cutting out unnecessary frequencies. So when looking for cheap bills and cooler weather it's not a bad option!

How many LED grow lights do I need?

To figure this out, you need to think in terms of coverage. You want your entire canopy to receive a fairly equal light intensity. A good grow light is often sufficient. However, if you have a large room with lots of plants, a combination of fewer larger lights or more smaller lights might work better. It all depends on the room and your decor. For example if you will useSO GÖScrOGtraining techniques, you must adjust your LED settings accordingly.

Growing Marijuana With LED Grow Lights

Using LED grow lights to maximize cannabis yields (6)

Using LED lights to grow marijuana is fairly easy, especially with full spectrum or switched lights. That means you don't have to change your rig. However, there are some important factors to consider at every stage of the cannabis growing cycle.

LED grow lights and the seedling stage

In the seedling stage, cannabis plants are at their most vulnerable and require the most care. If you use LED lights, be careful not to expose themseedlingstoo much light If your LED has a dimming option, you should use it. If not, move the light away a little. That being said, you must follow the directions of the plant itself. If it shoots up and starts looking lanky, you're not giving it enough light and it isrenewal. If you don't, you risk falling.

If your grow light has a Veg/Bloom switch, set it to Veg mode so it receives a blue spectrum. That helpsroot development, which is crucial at this stage. Switch to a light cycle of 18/6 for this phase, or up to 24/0 for autoflowering plants.

LED Grow Lights und die vegetative Phase

The veg stage requires more or less the same setup as the seedling stage, except your plants can receive a higher light intensity. You still don't want to burn them! Look for discoloration and curling on the top leaves. When you see it, move the lights a little further. Aside from increasing the light intensity, keep the settings as before.

If she's still growing upright, tall, and skinny, that's a sign your cannabis plant wants more light. Although it naturally grows tall, most healthy plants also exhibit plenty of bushy outward growth. The exception to this rule are somesativa strains, which appear to stretch regardless of environmental conditions.

(Video) When To Increase Light For Max Yield, for Beginners with Mars Hydro

Related articleThe vegetative phase of cannabis cultivation

LED grow lights and the flowering phase.

For the flowering phase, switch to the flowering (red) option if you have it. In order to get a photoperiod cannabis plant to flower, you need to set it on a 12/12 light cycle, otherwise it will continue to vegetate. Again, beware of lights that burn and expand and keep the grow light onoptimal distance.

Can you grow autoflowering cannabis with LED grow lights?

If you can. In general, it seems to work just as well as it does with photoperiod plants. However, there are some anecdotal reports of autoflowering plants freezing under LED lights in the early flowering phase. However, if this is true then it seems quite uncommon and shouldn't put you off trying.

How far away should my LED grow lights be from my marijuana plants?

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To answer this, you need to know the strength of your lighting and the growth stage of your cannabis plants. Combining the information above with the manufacturer's instructions should help you figure it out.

A major advantage of LED lights is that they can be placed much closer to your marijuana plants without burning yourself. This helps maximize light exposure and possiblyincrease yields! Play and watch your plants. Basically, you want your lights to be as close to the canopy as possible without burning the plants. Beyond the seedling stage, you can afford to find out what that distance is as long as you act quickly.

Related articleThe optimal distance between grow lights and cannabis plants

Can LED grow lights burn cannabis plants?

Although the LEDs can be placed much closer, they can still burn your plants. The good news is that it should be slower, and as long as you're vigilant you should be able to fix any problems before they do any real damage to your cannabis plants. Thanks to their coolness, the top leaves will not be fried immediately if the LEDs are placed too close together.

Are LED grow lights as good as HPS?

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This is a long-term debate that cannot rest here. In general, however, we would say yes. Certainly an old favourite, HPS have been responsible for the best quality indoor cannabis for decades, making many indoor growers reluctant to give them up. But while they certainly produce large yields of quality weed, they're expensive to run, hot, and cumbersome.

LEDs, on the other hand, are cheap to run, consume no power, and stay cool. This makes them much better for home growing as they are smaller and don't need ventilation. The downside is that unlike the HPS market, the LED market is not yet standardized and it can be difficult to figure out what you are actually getting. With HPS, you know exactly what's in the box.

(Video) What YOU have to Look Out for in a LED Grow Light!

Those are the differences in terms of settings, but what about the results? HPS are incredibly intense and tend to produce the biggest yields in terms of quantity. LEDs are less powerful and can produce slightly lower yields, but many claim they produce higher quality bud.

What is it you want? quantity or quality?

Using LED grow lights to maximize cannabis yields (9)

max sergeant

Max has been writing for over a decade and in recent years has been involved in cannabis and psychedelics journalism. Writing for companies such as Zamnesia, Royal Queen Seeds, Cannaconnection, Gorilla Seeds, MushMagic and more, he has experience across a wide spectrum of the industry.

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How many cannabis plants can I grow with a 100W LED light? ›

For a cultivation area or a grow tent of 80 x 80, you will need LED systems from 100W to 200W depending on the manufacturer. Any LED system between these watts will be enough to fully grow up to 4 plants.

How do you get big buds with LED lights? ›

Bud size may be increased through the following recommendations:
  1. Use an LED grow light with a spectrum that is best utilized by your plants.
  2. Place the LED fixture the correct distance from the canopy during the flowering stage.
  3. Create a footprint to deliver near equal amounts of light to all parts of the canopy.
6 Jan 2017

How much LED light does cannabis need? ›

The Amount of Light Required To Grow Different Types of Indoor Plants
Type of PlantAverage PPFDHours of Light
Fruiting Vegetables (Tomatoes, Peppers, Eggplant)400 – 5008 ON / 16 OFF
Cannabis in Vegetative Stage300 – 60018 ON / 6 OFF
Cannabis in Flowering Stage900 – 1000+12 ON / 12 OFF
3 more rows
11 Apr 2022

Do LED lights increase yield? ›

However, new and advanced LED lights not only offer equal light intensity; they also come with nuanced benefits that give growers more control than ever over their output. These days, you can count on LED lights to produce around 1-1.5 grams/watt, while the average yield for HPS grow lights is . 5 grams/watt.

Can cannabis get too much LED light? ›

Too much light can harm cannabis plants, and a thoughtful grower needs to be strategic about the placement and strength of light sources in a greenhouse environment.

How far should a 1000 watt LED light be from plants? ›

Lower wattage LEDs of around 200 watts should sit between 12-20 inches from the top of the plant. Higher wattage LEDs of 1000 watts and above should sit between 36-46 inches from the top of the plant.

How do you get super dense nugs? ›

  1. 5 Tips to Grow Dense Nugs. Prune Your Plants. ...
  2. Feed Plants What They Need. Giving your plants the nutrients they need is vital through each stage of growth. ...
  3. Train Your Plants to Increase Yields. Training your plants is another easy way to increase your yields come harvest. ...
  4. Don't Harvest Too Early.
16 Mar 2018

How do you get super tight buds? ›

Increasing the amount of CO₂ in your grow room can help you grow bigger, denser buds. By doing so, you'll help plants photosynthesise faster and encourage them to take up more nutrients and water.

How do you get super fat buds? ›

To some degree, more light translates to fatter buds and higher yields (you'll need to pay attention to the distance between your grow light and plants or your plant may suffer from light burn). Increasing light intensity is the most effective way to fatten up buds.

How many plants can I grow with a 300W LED light? ›

For example, one single 300W LED light fixture may be fine for one or maybe two plants, but it may not be enough to cover a bigger space with multiple plants. So make sure to reference any recommendations from the vendor and/or LED manufacturer on how much light you will need for your growing space.

How many plants can a 1000W LED light grow? ›

As such, it could provide solid coverage for up to 4 plants. Yield Lab 1000W HPS+MH Cool Hood Reflector Grow Light Kit (Price: $239.95) — With a 1000w grow light, you'll get 130,000 lumens from an HPS bulb and 110,000 lumens from an MH bulb.

Do LED lights yield more than HPS? ›

LEDs have much higher efficacy than HPS lights. LEDs are much more efficient than HPS lamps, which allows them to use lesser watts to achieve the same or higher output. The VOLT Grow® 720W FL-1 light produces a higher light output than a standard 1000W HPS light while using 30% less power.

Do LEDs speed up flowering? ›

Faster flowering can result in significant savings and better profitability for plant breeders. Various conditions can affect the flowering speed, but the quality of the light spectrum is probably the most important.

What happens if you put too much power into an LED? ›

LED lights require a certain voltage, such as 24 or 12V. When they run at higher voltages, they become extremely hot. Extreme heat damages the LED lights or the soldering around them. Due to the heat damage LED lights start to dim, flicker, or may die entirely.

Can you leave LED grow lights on all the time? ›

A: In general, you should not leave grow lights on 24/7. Plants need a light-dark cycle to develop properly. It's believed that they truly do “rest” during periods of darkness, and probably use this time to move nutrients into their extremities while taking a break from growing.

How do you know if grow light is strong enough? ›

Your plants will tell you if your lights are strong enough; weak, leggy plants indicate a need for more light. Most lights should be hung only a few inches from the plants.

What color light is best for cannabis? ›

Red radiation (around 700nm) is considered most efficient at driving photosynthesis – especially in the flowering stage for biomass growth (important to Cannabis growers). Blue light is essential for both the vegetative and flowering stages of plant growth, but mainly for establishing vegetative and structural growth.

What happens when LED lights are too close to plants? ›

Moving the grow light closer will increase the light intensity which can maximize photosynthesis. However, if the grow lights are too close above plants, they can cause wider, more sprawling growth or can even damage the plant. Plants require different levels of light depending on each stage of growth.

What size grow tent for 1000 watt LED? ›

4' x 4' Grow Tent - Perfect for the footprint of a 1000w HID or LED grow light (4-6 plants)

Should I dim my LED grow lights? ›

When it comes to whether or not you should dim your grow lights, the answer should be “no.” Your grow lights are not like your typical household lights. Your plants depend on indoor grow lamps to be operating at 100 percent in order to get the full benefit of your bulb's light spectrum.

What is the best bud hardener? ›

General Hydroponic KoolBloom

Available as Liquid KoolBloom or Dry KoolBloom, this additive is widely regarded as the best bud hardener out there.

Why are buds fluffy and not dense? ›

These airy flowers are often the result of suboptimal growing conditions, a lack of light, or nutrient deficiency. Fluffy buds don't only look less appetising, but you'll need to use more of your harvest every time you roll a blunt or hit a bowl.

What causes airy nugs? ›

One of the causes of airy buds is too few nutrients. Waterlogged soil is also dense and doesn't have a lot of air pockets. Starving the roots of oxygen means the rest of the plant is not getting the support it needs to be strong and healthy. Over time this results in weaker stems, flowers, and loose buds.

Should I cut off big fan leaves? ›

Should you remove fan leaves? Yes, removing or pruning some fan leaves is a necessary step when cultivating cannabis healthy plants. When fan leaves become too large or abundant, they block the light and airflow to parts of the plant that can hinder trichome and cannabinoid production.

What week do buds swell the most? ›

Weeks 1-3 – Transition

Also known as the flowering stretch—you'll notice a sudden increase in growth over these three weeks. Your plant needs to be big and strong enough to support the buds that'll be growing over the next few weeks—it can double or even triple in size.

Does bigger pots mean bigger yield? ›

Pot size will have an effect on the final yield. Put simply, a bigger pot means a bigger potential harvest.

How can I speed up my flowering? ›

If plants have a short-day response, then shortening the days by totally excluding light from the plants for 12 hours per day will accelerate flowering.

How many plants can I grow with a 400w LED light? ›

Generally, grow lights that use 200-400w's can grow around 1-3 plants per light; lights that use 500-700w's can grow around 4-5 plants per light; and lights that use over 800w's of power can grow 6-8 plants per light.

How many plants can go under 600W LED? ›

Each 600W grow light covers roughly a 1.2m x 1.2m area. That's enough space for 1 - 4 plants.

What is the highest yielding grow light? ›

High-Intensity Discharge lights, or HID for short, has traditionally been the most commonly used type of grow light. This is because they produce the largest amount of useful light and usually result in the greatest yield. There are generally two types of HID light bulbs – HPS bulbs and MH bulbs.

How much does it cost to run a 1000w LED grow light? ›

You need to divide your wattage by 1,000 (1,000 kilowats in 1 watt). So, if we were to run a 1000 watt grow light 18 hours a day with the kWh rate we gave earlier, our formula would be: 1 x $0.1559 x 18 x 30 = $84.186/month. $120.00 on sale until 12/24/2022! $249.00 on sale until 12/24/2022!

How many watts do I need for 2 cannabis plants? ›

Recommended wattage assuming 2.0 sq ft/plant
# of PlantsSquare FeetWattage from Wall
1260 to 80 watts
24120 to 140 watts
48240 to 300 watts
612360 to 400 watts
2 more rows
8 Sept 2014

How many grow lights do I need for 2 plants? ›

How many plants per LED grow light?
Grow Room SizeSquare FeetRecommended # of Plants in Veg
1' x 1'1Up to 2
2' x 2'4Up to 4
3' x 3'9Up to 9
2' x 4'8Up to 8
6 more rows
5 Mar 2021

How big of a grow light do I need for 4 plants? ›

A good rule-of-thumb for LED grow lights is 32 watts of actual wattage per square foot of growing space for flowering medical or other large flowering plants.

How far should a 100 watt LED light be from plants? ›

LED grow light distance chart
LED grow lights WattageDistance from Plants
250- 400watts16 to 30 inches away from your plants
450- 550 watts20 to 30 inches away from your plants
600- 800 watts28 to 42 inches away from your plants
900- 100 watts36 to 46 inches away from your plants
4 more rows

Does more wattage mean more yield? ›

If you're using an HPS light, you should remember that more watts don't necessarily lead to higher yields. Plants can only utilize that extra light if they are also supplied with extra carbon dioxide.

What is the average yield for indoor cannabis? ›

Many factors affect how big a plant gets, but generally speaking, if you are growing a healthy plant, you can expect these yields from one weed plant: Outdoor plant: ½ pound of buds, or about 224g. Indoor plant: ¼ pound of buds, or about 112g.

What is a good cannabis yield per square foot? ›

But really the 30 to 35 (grams) is the low bar, and if growers can achieve 50 or even 70 grams per square foot, then they're really in the ballpark. That's when you become productive and really lucrative. Q: What are some key considerations for creating optimal environmental conditions to boost yields?

Can you overuse a grow light? ›

Plants can't gorge on artificial sunlight forever.

Do you leave grow lights on 24 7? ›

A: In general, you should not leave grow lights on 24/7. Plants need a light-dark cycle to develop properly. It's believed that they truly do “rest” during periods of darkness, and probably use this time to move nutrients into their extremities while taking a break from growing.

How many plants can I grow with a 1000w LED light? ›

This HPS and MH grow light kit will provide the necessary lumens to up to 6 plants in a 5x5 grow tent through the vegging and flowering stages. The power of this 1000w light is perfect for providing the coverage and depth to reach all of your plants.

How many plants can a 600w LED grow? ›

Now, it's also important to understand that most LED grow lights will usually only be able to cover around 1- 6 plants.

How high should I hang my LED grow light? ›

Hanging Lights Too High

VOLT Grow® LED grow lights are designed to be mounted between 6-12 inches from the canopy for maximum yields. This close proximity is possible because they produce substantially less heat than their HPS counterparts.


1. Indoor LED Grow Lighting & Maximizing Yield: A LED | TALK by DAZOR
(Dazor Grow Lights)
2. Best Grow Lighting for Cannabis with Dr Bruce Bugbee | Far red ePAR
3. How Far Should LED Grow Lights Be From Plants? - FAQ
(California LightWorks)
4. Customer Feedback | Led Grow Light Max Yield
(Plentiever LED Grow Light)
5. TRUTH ABOUT MICRO GROWING IN SMALL SPACES! ... How to maximise yield?
(The iCanTHC Channel)
6. Cannabis Grow Lighting Myths and FAQs with Dr. Bruce Bugbee
(Apogee Instruments Inc.)


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