September 24, 2022

Growing with LED lights: using LED grow lights for cultivating cannabis

LED grow lights represent a major leap in technology over traditional HID lights, and are gaining in popularity every year. Growing with led lights is a better experience for several reasons. These include convenience, light intensity, and efficiency. The main drawback has always been price, but that has been coming down every year as the technology matures.

Types of LED grow lights

There are three main types of grow lights. Each type of LED grow light has its pros and cons, so there isn’t a universal “best” type of grow light. Different LED grow lights are best for different situations, so pick the one that works for your custom setup.

Traditional panel

Traditional panel led grow lights are the original grow light type, and are also the most common and popular LED grow lights in use today. These panels tend to be fairly compact with small to medium wattage diodes (3-5 watts per LED). Traditional panels are often referred to as purple lights, as their red and blue LEDs together emit a purple grow.

Traditional panel LED grow lights are the least expensive out of all the grow light types. There are many inexpensive brands available that use cheap overseas manufacturers. Of course, cheaper products generally mean lower quality. An inexpensive LED panel can have many issues, ranging from lack of light output to cheap or faulty parts.

Many new “hybrid” LED grow light panels are starting to appear. These are similar to traditional panels, but use a mix of small and medium diodes rather than all medium diodes. These hybrid panels are attempting to be the best of both worlds by merging traditional and cob style lighting.

Cob style

COB is an acronym that stands for “Chip on Board” This style of led grow light uses larger single bulbs that are covered in individual LED chips, where every chip produces some light. Since these bulbs pack so many chips into a small area, they are able to produce very intense light.

COB boards tend to have a few large bulbs rather than a large amount of individual LEDs. These bulbs are spread out rather than packed closely together, and have lenses to direct their light downwards. COBS are a popular choice due to their light intensity and good light penetration into cannabis plant canopies.

The drawback to these is that they are pricier than other LED grow light types. Additionally, these light types are the most energy intensive light type as well.

Auto cobs

Auto COBs are a singular version of a COB board, where each bulb is sold as a stand alone individual light. These lights are then arranged together above a plant canopy, with enough spacing to cover the entire grow area.

It’s important to remember that auto COBs each have their own limited spectrum of light, whereas LED panels usually have a full spectrum of light. Individual auto COB bulbs will only have part of the spectrum such as blue light, green light, or red/infrared light. Growers will need to pick the bulb combinations that they need for the spectrum that they want to use.


Spread-style LED grow lights have numerous smaller wattage LEDs spread out over a large area. These board styles are gaining popularity due to the fact that they produce very good results with relatively low energy costs. The drawback to this type of LED grow light is that they are still very expensive. There are two main types of spread-style LED grow light solutions.

quantum board

Quantum boards are a rectangular panel or board that uses the spread-style design. These boards have many smaller LED diodes spread out over a larger area.

Spider LED

Spider LED grow lights use a slightly different design than a quantum board. They use long, skinny boards to hold their LEDs. These boards are attached perpendicular to a main board that travels the length of the grow area. These grow lights are well liked by those that have tried them, their main holdback is the price.

LEDs explained

What are LEDs

To understand why LED lights are so different from traditional bulbs, we need to know what LEDs are. LED stands for light emitting doide, where electricity passes through a microchip which then illuminates the light source. Each LED also has a small heat sink to absorb excess heat.

Standard incandescent bulbs pass current through a wire, which then emits heat and light. This method is more inefficient than LEDs, which leads higher energy costs due to heat waste.

LED grow light spectrum

Healthy plant growth requires that the plant absorb certain wavelength light from the light spectrum. The light types that plants require are generally red/infrared light and blue light. LED grow lights are very good at targeting blue light and red light with specialty LED chips. Each type of light has different benefits for growing cannabis plants.

Red light

Red light is a lower wavelength light. For plants, it boosts the production of flowers and fruit. This wavelength of light is most useful to growers during the flowering stage of a grow. Flowering plants benefit immensely from red wavelength light, which can help boost bud yields.

Blue light

Blue light is a shorter wavelength light that is critical for plant growth. It boosts the production of stems, roots, and other vegetative growth during the plant’s growth stages. This wavelength of light is most useful during the earlier stages of a grow, such as the seedling stage and vegetative stage.

Infrared light

Infrared light is even longer wavelength than red light. This light type is absorbed by the phytochromes in a plant. This type of light is used in plants to regulate their circadian cycles for things like seed germination and bud blooming. Adequate infrared light can help cannabis plants as they transition from the vegetative stage to the flowering stage.

LED grow light advantages

Grow lights have many advantages over traditional types of lights, and represent a big leap forward in terms of technology. There are several big benefits to using LED lights:

Energy efficient

LED grow lights are very energy efficient, as they are very good at turning their energy into light, rather than burning energy off as heat. In fact, LED grow lights can be up to 75% more efficient than traditional bulbs.

This benefit is not only helpful for the environment, but it also saves growers money over time. In fact, in the long run, it’s possible to offset the high initial costs of LED lights through energy savings.

Long lasting

LED grow lights last much longer than traditional grow lights. This not only leads to a reduction in general waste, but saves money on replacement parts and also the labor and inconvenience of replacing lights.

When traditional grow lights get old, they gradually lose light intensity over time. This means that even if the lights haven’t gone out, they may be underperforming. LED grow lights are much better at maintaining performance throughout their lifetime.

Less heat

As previously mentioned, LED grow lights are very good at converting energy to light rather than heat. Therefore, LED lights give off far less heat compared to traditional grow lights. The lack of heat can be a major selling point for growers who have to work under these grow lights.

Climate control is a very important part of maintaining a proper grow room. The biggest issue with climate control is too much heat, often generated by traditional grow lights. This heat has to be controlled through ventilation and air conditioning. Grow rooms with LED lights have easier climate control.

Due to their lower heat, LED grow lights can be placed closer to plants. Traditionally grow lights carry more risk of heat burn for plants. While LED lights still must be kept a proper distance from the plants, they can be kept in closer, which is especially useful for growing in small areas.

full spectrum lighting

LED lights are convenient because provide the full spectrum of light. They provide both the blue and red light that plants require in one LED panel. Other light sources, such as HID grow lights, require special blue light blubs for the vegetative stage of a plant’s growth. Then once the plants begin to bloom, they must switch out the bulbs to red light. LED grow light owners can keep the same lighting setup for the entire grow.


LED grow lights generally have everything that a cannabis grower needs right in the panel. All the grower needs to do is hang it and plug it in. For traditional grow lights, this isn’t always the case. For example, HID lights require many separate parts including blubs, reflectors, ballasts, and controllers.

LED lights have less moving parts and can be more convenient to set up. Additionally, less parts means that these panels can fit into smaller growing areas, which can be useful for cultivating cannabis in tiny spaces.

less need for watering

Cannabis plants need regular watering to keep their soil from completely drying out. Traditional grow lights run hot, which generates heat that dries soil faster. With cooler LED lights, watering needs are less frequent.

Proper LED grow light distance

To maximize your cannabis plant’s growth, grow lights should be kept an optimal distance from your cannabis plants. If the lights are too far away, they won’t provide your cannabis plant with enough light and energy to grow. If they are too close, it may lead to issues such as light or heat burn.

Although LED grow lights run much cooler than traditional grow lights, there is still a risk that you can give your cannabis plants light burn if they are kept too close. The risk of light burn is due to the higher light intensity of LEDs, and not necessarily from any excessive heat.

LED grow lights work well in confined spaces due to their compact nature and lack of heat. However, novice growers may take this too far and place their lights too close.

Optimal distances depend on the wattage and light intensity of your LED grow lights. Below is a rough guide for distancing your grow lights.

Optimal LED light distance by wattage

  • Sub 150W: Can be kept a little less than 1 foot away
  • 150-300W: Should be kept a little less than 2 feet away
  • 300W: Keep over 2 feet away.

Adjust as necessary

The above numbers are a rough guide on distancing your grow lights. Indoor growers should adjust their light distance over time based on the observed reaction of their cannabis plants. The rule of thumb for your grow room should be to get the lights as close as possible to the plants without them getting light burn.

LED grow lights vs other grow lights

While LED grow lights are a great option for anyone looking to set up a grow room, there are two other popular options available. Popular options include CLF (compact fluorescent) bulbs and HID lights. Both of these options have some benefits and drawbacks compared to LED lights. Growers will have to choose the best option for their individual setup.


CLF bulbs are the lowest cost option for growers. These bulbs are readily available, cheap, and work well for inexpensive or small grows.

CFL advantages

  • CFL lights are much cheaper than LED grow lights.
  • They are also fairly low heat like LEDs, although they do generate more heat overall.
  • CFLs are lower light intensity, so they can be placed very close to the plants they are growing with little risk. This is good for growing cannabis in small spaces.
  • Due to the factors above, they are a good option for beginner growers and also growers on a small budget.

CFL disadvantages

  • CFL bulbs don’t last as long a LED lights
  • These bulbs are less energy efficient than LED lights, which means lower light intensity for higher energy costs
  • CFL bulbs may need to be placed closer to the grow due to their lack of light intensity. This can be annoying for growers trying to light up a wide area with one panel.


HID lights are a very popular option for indoor growing. These lights produce a lot of wattage and are very cheap. Unfortunately, they also have several drawbacks compared to LED grow lights.

HID advantages

  • HID lighting setups are high wattage like LED grow lights
  • These lighting setups can be a good initial value because they are also relatively inexpensive.

HID disadvantages

  • HID lighting setups are high wattage but they generate a lot of heat. Therefore they often have require good distance from plants and cooling solutions for grow tents.
  • These lights aren’t as energy efficient as other options, so they cost more money to run.
  • HID lighting requires several pieces of equipment to make work, such as reflectors, ballasts, controllers, and other items. These can be cumbersome to set up and take up more space.
  • One HID grow light won’t have the complete light spectrum needed to grow plants to maturity. Instead, separate lights will be needed for the flowering stage and vegetative stage. Keeping and switching bulbs can be rather cumbersome and inconvenient.

LED grow light tips for the cannabis life cycle

The lighting needs of cannabis plants change over the course of their lifecycle. This includes phases in the seedling, vegetative stage, and flowering stage. Adjusting to the needs of your plant in each stage can help maximize your plant’s health and eventually your harvest yields.

Seedling stage

Seedlings are the first stage of growth when a cannabis plant sprouts from its seed. At this stage, the plants are small and fairly delicate. For seedlings, it’s important to avoid overexposing your plants to too much light. If our LED grow lights are strong, make sure to turn down the intensity a bit or keep the lights slightly further away for the plant than normal.

Seedlings in their initial stages need about 16 hours of light and 8 hours of darkness per day. This lighting schedule will ensure that the plant gets lots of light and will match the plants own circadian clock. The easiest way to keep a light schedule is with an inexpensive light timer, automating this will ensure a proper light schedule and save you maintenance time.

Some LED grow lights have a switch and separate mode for the vegetative stage and flowering stage. While LED grow lights already use full spectrum light for the most part, the switch will cause the light panel to emphasize blue or red light depending on the stage. For seedlings, this switch should be set to the vegetative stage.

Keep in mind that the adjustments to light intensity in this stage should be small. Over adjusting and reducing your light too much will cause your seedlings to grow lanky and skinny. Seedlings still need a lot of light as they are growing a lot. Observe your plant and make adjustments as necessary.

Vegetative stage

Plants in the vegetative stage require around 16 hours of light per day to grow big and dense. This stage is where the plant has its biggest growth spurt, gaining a lot of size by growing out its stems, branches, leaves, and root system.

Plants in this stage require lots of light to grow to their potential. In fact, good lighting is the number one thing that will lead to a big harvest. Make sure that your LED grow light is set to the vegetative stage (if your lights have such a switch or mode) to ensure that your plant is getting the right spectrum light.

Flowering stage

Most cannabis plant types rely on lighting cues from their environment to determine when they should begin flowering. To induce flowering in your plants, you will need to reduce the hours of lighting from 16 down to 12. Cannabis plants naturally flower in fall when the days get shorter. By reducing their light hours, your are mimicking their natural flowering environment.

Most growers will induce their flowering stage about 8 weeks into a grow cycle. Of course, this can vary by plant strain and also the growing method of choice. Some growers like to keep their plants and growing cycles short.

It’s important that your lighting environment gets no light pollution during the 12 hours of darkness per day. Any light that gets through to the plants can disrupt their circadian rhythm and revert them back to their vegetative stage. Indoor growers can use something like a grow tent to keep light out.

Plants in the flowering stage need the most light that they can get. In this stage, plants direct all energy from stem, root, and leaf growth to their bud growth. Lots of light during the flowering stage is the biggest thing that will ensure that you grow dense buds. Make sure to switch your LED lights to flowering mode your panel has such a switch.

LED grow light tips for autoflowers

Autoflowers are popular with beginner growers because they flower on their own and are fairly durable. If you own an autoflower plant, you don’t need to concern yourself with reducing the hours of light to induce blooming.

Keep the number of light hours high so that your plant gets all the energy that it needs to grow bigger buds and a larger yield. While autoflowers can grow on their own, they still benefit greatly from the light intensity given by a strong grow light.

Can you use regular LEDs as LED grow lights?

Some small growers are interested in using regular LEDs, such as LED bulbs or even things like LED screen readers, to grow their cannabis plants. So it is possible to use regular LEDs as LED grow lights? The answer to this is yes it’s possible, however there are some drawbacks to using this method.

Low light intensity

The first is that optimal plant growth requires high light intensity. One or two regular LED bulbs might not generate the intense light needed to grow your plants. So while regular LED bulbs generate light, and might technically be enough to support a plant, your bud yields will be very underwhelming.

Incorrect light spectrum

The second issue is that regular LED lights are generally “full spectrum”, meaning that they produce the full spectrum of light wavelengths which creates a white light. This white light is what consumers prefer for lighting their homes.

LED grow lights are occasionally referred to as “full spectrum” as well, but this refers to the spectrum needed for good plant growth. When growing plants indoors, cannabis growers need a combination of blue and red/infrared light. So even if a normal LED provides some blue light and red/infrared light, it may not be in the amounts required for strong plant growth.

LED colors

Most LED grow lights have a purple color to them. The reason for this is that LED grow lights are mainly designed to provide red and blue light for cultivating plants. The combinations of red and blue creates purple light.

Some growers find purple light to be uncomfortable to work under, and prefer something like white light. White light is full spectrum, meaning that it also includes green light wavelengths. This type of light can be easier on the eyes, but can be less optimized for plant growth than lights that focus on red and blue.

Concluding thoughts

LED grow lights are a great way to enhance your indoor grow setup. There are several options for LED grow lights such as traditional, spread-out, and COB styles. They have numerous benefits such as efficiency, power, lower heat, and convenience.

Their drawback is that they are an expensive option. There are other lighting solutions available as well with their own benefits and drawbacks.

LED grow lights can be use throughout a plant’s growth cycle to aid their growth and development.

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