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How to Grow Cannabis Using LED Lights

It used to be that lighting was one of the most expensive aspects of growing marijuana. A good set of HID or CFS lights could set you back a couple hundred with all the required equipment. Now, thanks to LED lights , cannabis grow lights are much more affordable, making growing cannabis at home much more attainable.

Growing Cannabis Using LED Lights

Related: 4 Best Grow Tents for Growing Marijuana

Different Types of Cannabis Grow Lights

The main types of cannabis grow lights are HID, or high-intensity discharge, CFL or compact fluorescent lights, and of course, LED or light-emitting diode lights. HID lights were the most commonly used cannabis grow lights when indoor growing first became popular in the 1990s. This was because they produced just the right number of lumens to grow cannabis indoors.

Though they work exceptionally well, HID lights are not without issues. For instance, a good setup is very expensive. If your plants don’t produce to your liking, you could find yourself out a few hundred dollars with no way to make your money back.

Those who could not afford a good set of HID lights would resort to CFLs, which, while not as effective during the flowering phase , managed to get the job done most of the time. Often times, these were the only options for growers with smaller operations, or those growing a couple plants for personal use. CFLs have gained some popularity over the years, but they would never be as popular as HID lights, which are trusted by growers all over the world. That is until LED lights entered the picture.

Why Use LED Lights?

There are many reasons to use LED lights when growing cannabis.


For many, the main reason is that they are relatively inexpensive when compared to the much pricier HID setup. This is especially true if you are growing a smaller number of plants. Our grow lights at A Pot for Pot are specifically designed for growing a small number of marijuana plants and is priced well under $200 – proof that high-quality lighting doesn’t need to be expensive.

This was not always the case. When LEDs were first gaining momentum among growers, the technology was still fairly new and had not entirely been perfected. Think about how expensive and inconvenient cutting-edge technology like smartphones were when they first came out, and it often wasn’t worth it. For example, many agree that the first-generation iPhone was not the greatest. However, today’s smartphones are much more affordable, and they are everywhere.

Energy Savings and Privacy

Another thing to consider is how much money LED cannabis grow lights will save you on your energy bill. HID lights are good at what they do, but the amount of energy they use will cause your energy bills to skyrocket. This not only hurts your pocketbook, but it can also draw unwanted attention in your direction either by a landlord, a nosy neighbor, and/or the police. When people had to keep their marijuana growing activities under wraps, spiking electricity bills often gave them away. While cannabis is legal in more areas now, this does not necessarily mean that you want the whole neighborhood knowing what you are up to.

Reduced Water Usage

Not only are LED lights more energy-efficient , but you’ll also save on water usage as well. As you are now aware, HID lights use a lot of energy, which in turn produces more heat. This dramatically increases the temperature of the grow room, causing your plants to consume more water. Cannabis is already quite the water hog when compared to other plants and growing even just a small amount of plants uses a lot of water. Any way to reduce water consumption is great for the environment, not to mention great for your utility bill.


Finally, LED lights last longer than HID or CFL bulbs, ensuring many years of good use before they need to be replaced. Traditional cannabis grow lights last for only 20 thousand hours. In contrast, LED bulbs last more than twice as long, for up to 50 thousand, or sometimes even 100 thousand hours. That’s five times the life of HID lights!

Convinced? Check out A Light for Pot to start growing cannabis with LED lights.

Start Growing with LED Lights

Cost is not the only reason to make the switch to LED lights . Experienced growers know that seedlings and plants in the vegetative stage benefit more from blue light, while flowering plants need red light to thrive. Before LEDs, growers would have to purchase two different types of lights: metal halide for the vegetative or blue light stage, and high-pressure sodium bulbs for the final flowering stage.

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With LED cannabis grow lights, this is not the case. Different color LED bulbs give a grower the ability to manipulate the color spectrum, thus allowing you to use the same light setup for both phases of growth. This not only eliminates the need to purchase two different types of lighting setups, but you’re also guaranteed the best results in your plants!

The benefits of using LED cannabis grow lights are many. The next big question is how to grow marijuana using only LED lights. A good rule of thumb is one light per every 1.5 square feet. This generally will yield you up to 6 ounces per plant, which ends up covering what you spend on the light and will definitely end up saving you money in the long run. If you are growing only 1-2 plants, our single 75 watts LED light supplies plenty of light for your plants.

Even if you’d like to grow more than a few plants, you don’t have to go for the more expensive HID lights. Simply add to your setup with either a few larger LED bulbs or several of the smaller ones. If you opt to go for the latter option, make sure that your plants and your lights are spaced out correctly, as you want to make sure that each plant gets adequate amounts of light. Using too few lights can cause stretching, whereas using too many lights leaves you at the risk of light burn, as well as energy overconsumption.

If you are willing to step up the quantity of your grow, that is, really take it to the next level, you should be prepared to spend a little bit more cash. A large scale 350-400 watt LED operation that will outdo the average 600 watts HID lighting system is not going to come cheap. However, a larger LED light setup will still be more cost-effective than an HID setup of the same size.

Related: Smell-Proofing Your Indoor Marijuana Grow Room

Drawbacks to LED Lights

If there is one drawback of using LED grow lights, it is that your plants’ grow time will be slower than if you were using HID lights. Again, this is because HIDs emit more energy than LEDs, leading to faster flowering.

You should also be aware that while LEDs don’t put out as much energy, your plants are still susceptible to light burn. So, like any other lights, make sure that you are keeping your lights a proper distance from your plants and keep plants dry when under direct light.

With LEDs, you don’t have to place your plants as far away as you would with HIDs. Keep lights below 300 watts about 30-70cm away, or just around 12-27 inches. Lights above 300 watts should be kept at 70-80cm away, while gradually decreasing space when flowering. Larger wattage like 450 should be close to 80 cm or 31 inches.

Be careful when making any changes to your light setup. Decreasing the space between plant and light too quickly might have detrimental effects. Keep an eye on your plants and take it slow!

Grow Light Distance Chart: How far should my Grow Light be from my Marijuana Plants?

How far you hang your grow light from your marijuana plants depends on the power, wattage, and size of your grow light. You should always find out the wattage and the distance specified for the grow light before using it using a grow light distance chart (see below!). This way, you can ensure you get the maximum yield and potency from your plants.

In most cases, the grow light manufacturer will specify the distance grow chart on the packages, so read your directions carefully! If you already threw away the packaging, a quick google search will save the day — simply search for your light manufacturer + light wattage .

If you still doubt the distance to hang your LED grow lights, choose a distance based on the info below and watch them daily for signs of bleaching, then back the lights off or change the light’s proximity to the plants when you notice any.

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Here is a simple LED Grow light distance chart to help you

Grow Light Closest Sunlight Furthest
150W 8″ (20cm) 10″ (25cm) 12″ (30cm)
250W 10″ (25cm) 12″ (30cm) 14″ (35cm)
400W 12″ (30cm) 14″ (35cm) 19″ (48cm)
600W 14″ (35cm) 16″ (41cm) 25″ (64cm)
1000W 16″ (41cm) 22″ (55cm) 31″ (79cm)

How far should grow lights be from a marijuana seedling?

You should always regulate the heat and light intensity of marijuana seedlings. Place your marijuana seedlings 6-12 inches away from the grow light. You can double the distance of the grow light as your plants mature and grow more leaves.

What happens if I place my grow lights too close to my cannabis plants?

When you place the grow light closer to your cannabis plants, they are likely to bleach. The plant leaf will burn if they are placed too close to the heat of the bulbs. They can also start drying soon after the flowering stage, and this affects your yield and potency. Thus, it may not be the best quality for various uses of cannabis plants. Always use the indoor grow lights as recommended by lighting experts.

Can you leave grow lights on 24 hours a day?

No, you should not leave the grow light on for 24 hours a day. Knowing how much daily light integral (DLI) your marijuana plants require is an essential step in ensuring you have a healthy grow op. Marijuana plant seedlings need some dark cycle to mature well. In general, plants also ‘rest’ in the dark period and use this time to take a break from growing and extracting nutrients from the soil and extremities. Therefore, you should give your marijuana seedlings at least 12 hours of light and switch off the lights for the rest of the day.

Which is the best light colour for plant growth?

Plants need light to achieve different growth goals. For vegetative growth, marijuana plants will require blue light. Blue light combined with red helps the plants to flower. If you are cultivating your flowering plants indoors, you should expose them to fluorescent bulb lights.

You can add or remove some grow lights depending on the stage of plant growth. Although blue and red are the most important colours for plant peaking, other colours are also useful to the plant. Sunlight is a combination of several colours, that is why plants exposed to sunlight grow healthy at different stages.

Will any LED light work as a grow light for indoor plants?

Yes, LED lights can work as a light for indoor plants. Most people prefer using LED lights because they are energy efficient. They also emit a lower amount of heat and white light, which means you can use them as grow lights. White light contains a mix of colours which is great for plant growth.

The only downside of cheap LED lights is that they can easily damage, cause burns to plants when you don’t position them well. Also, there is a lack of standard specs from various LED manufacturers.

Can you use regular bulbs as grow lights for plants?

Grow lights are more expensive than regular bulbs. Yes, you can use regular bulbs as grow lights in some cases. Generally, you should use regular grow bulbs for an indoor plant . However, if your plants are not getting enough light, you can change to grow light for the best results. Regular bulbs are most likely not the best thus it would be ideal if you can manage to buy the recommended grow lights.

How do you know if your plants are not getting enough light?

You can tell if your marijuana plants are not getting enough light by checking a few factors:

  • The plant will be taller with weak stems as it strives to get closer to the light.
  • The leaves will be a bit light in colour because they will be lacking chlorophyll, which is a key component of photosynthesis.
  • The plant will form new broad leaves, and the plant’s inner part will turn yellow.

If you are growing marijuana indoors , consider bringing the light source closer to your plant.

How far apart should grow lights be from each other?

You should always space your grow lights 4 inches apart. However, the distance from each bulb will vary depending on the size of the bulb and the grow light wattage. You can also change the distance to the plant as the canopy changes.

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What should I consider when shopping for grow lights?

When shopping for grow lights, you should know where you plan to use the lights, how many seedlings you are planning to grow, and what kind of lights you need. For normal plant growth, you may need a traditional fluorescent bulb or energy-efficient LED lights.

Are our house lights good for plants?

It is highly unlikely that your house lights will be good for your cannabis plants. If you no longer use halogen or incandescent bulbs, it is unlikely that the light in your house will be enough for the plants. The light in your house is not designed to provide the spectra that marijuana plants require for growth and development.

How much is an indoor grow light?

How much you pay for a normal grow light depends on the brand you want and wattage. A 24-Watts LED T5 tube costs $25, and a 54-Watt HID T5HO fluorescent tube may cost up to $5.20. You are likely to spend more if you are buying grow lights for vegetative and flowering phases. For instance, it costs up to $1,524 for a 630- Watts LED grow light used when marijuana plants are in the flowering stage.

Which are the best grow lights for marijuana plants?

The best grow lights for marijuana plants are HID, fluorescent bulbs, and LED. Fluorescent bulbs are the best for small grows and compact plants. Quantum-board LED lights are energy-efficient and therefore save you on electricity costs (see quantum boards by MARS).

Know you know how far your LED grow lights should be from your marijuana plants

You should place your grow lights at least 12 inches away from the plants. If you want your indoor cannabis plants to grow healthy , place the grow lights within the recommended distance and choose the right LED, HID, and fluorescent bulb for the task.

Not every bulb you buy can be used as a grow light. Therefore, you should find out if the bulb is rated as grow light before buying it. Place the lights at least 4 inches apart, keep watching the leaves, and adjust the proximity to the plant as they mature. Now you know what it takes to use the best LED grow light for marijuana plants.

1. How far from plants should a grow light be?

LEDs should be between 12 and 30 inches from the ground. Be mindful that the height of the lights may need to be different than the height of the growing plants, and it might change depending on the wattage of your lights, the plant variety, and the ambient light level.

2. Should I leave a grow light on 24 hours?

In general, it’s best to not leave lights on 24/7. Plants need darkness to develop properly. It’s believed that they really do rest during periods of darkness, and probably use this time to relax and move nutrients to their position in order to grow.

3. Can plants get too much artificial light?

Indoor plants typically require an hour to 12 hours of artificial fluorescent light to flower properly. If the light is too bright, plants will grow spindly and if they have too much light they will dry up and wilt.

4. Can LED lights burn plants?

LED lights are not harmful to plants. LED stands for light emitting diodes, which is a type of semiconductor that produces white light. The only potential way that plants could be harmed by the use of LED lights would be if they were in the direct line of sight with an intense beam and it was strong enough to burn them.

5. How many plants can a 1000W LED light grow?

As such, it can cover up to four plants with a 1000w grow light. Yield Lab 1000W HPS+MH Cool Hood Reflector Grow Light Kit (Price: $239.95) — With a 1000w grow light, you will receive a total lumen measurement of 130,000 from an HPS bulb and 110,000 from an MH bulb. So you are able to cover up to six plants with a light like this.