Starting Weed Seeds With Led Lights

Learn how blue light for cannabis works to increase vegetative growth for healthier plants and better yields and gets up to 50% more terpenes at harvest! Grow lights are a great tool for making the growing process more efficient. Here are 10 things you should avoid doing when using LED Thinking about growing cannabis? Here’s why you should consider LED lights and how you can use them.

Blue Light for Cannabis Cultivation Grow Lights – Part 1

Thanks to advancements in LED technology, modern LED grow lights can create just about any light spectrum. And that has growers asking: what’s the best lighting spectrum for cannabis?

In this three-part blog series, we explore what researchers have to say about the lighting spectrum, and how plants are actually responding to individual wavebands of light — otherwise known as colors. This blog discusses blue light and shares a simple blue-light trick for big increases in terpenes.

Blue Light for Cannabis

When we talk about colors of light, we’re really referring to their wavelength; it’s the wavelength of a light source that makes it appear blue, or red or green. The visible light spectrum spans from violet/blue light which has short wavelengths (ranging from 400-500 nanometers) to red light, which has the longest visible wavelength of around 700 nanometers.

Because of its short, high frequency wavelength, blue light carries a lot of energy relative to other colors. In fact, if its wavelength was any shorter, it’d fall outside the visible light spectrum into the territory of powerful ultraviolet light.

How Blue Light Effects Cannabis

Blue light is critical for cannabis. If blue light levels are low, cannabis plants experience a shade-avoidance syndrome that causes them to stretch. That’s because, to the plants, a lack of blue light signals that they’re in the shade of other, taller foliage.

More specifically, it’s the green-to-blue ratio that signals shade. Greenlight penetrates into the canopy while blue light is mostly absorbed. So, when the green: blue ratio is high, the plants think they’re shaded. And that’s why it’s important to include blue whenever you’re providing plants with high-intensity broad-spectrum light that includes lots of green.

When cannabis isn’t getting enough blue light, it’ll compete for exposure by growing longer shoots and eventually exhibit leaf hyponasty (an upward curl of the leaf surface). That’s not a good thing — at least not in the opinion of indoor cultivators who want short, manageable plants. Without any blue light, plants get unruly, tall, and poorly adapted for flowering. Because they’re busy stretching for light, they fail to develop the root system that’ll support their nutrition when it’s time to bloom.

Blue light also regulates the opening and closing of stomata. Stomata are the tiny pores that allow gas exchange and CO2 intake. This gas exchange is critical for bringing in the CO2 needed for photosynthesis, and also for cooling the leaves through the release of moisture. For that reason, most sole-source lighting fixtures include at least some blue light. Even high-pressure sodium (HPS) lights, which are strongly red-dominant, have a little blue.

Which Grow Lights Have Blue Light?

During the vegetative growth phase — when plants are establishing the foliage that’ll drive photosynthesis over the course of their life cycles — indoor growers make sure to give their plants lots of blue light. In the past, that meant using metal halide (MH) lamps that were rich in blue wavebands. Now, growers can select an optimized LED spectrum or an LED fixture with tunable wavelengths. Spectrum tunability allows cultivators to increase — or decrease — the amount of blue light they’re providing their plants as the production cycle changes.

But when we look at horticultural lights, pure blue light won’t seem as bright as other colors. Our eyes are less sensitive to blue and more sensitive to mid-spectrum wavelengths like green. That’s why a light with lots of blue will seem less powerful than it actually is. If light were to produce only blue light, it’ll appear dimmer than a light-producing only green or amber light. Yet blue light matters to plants, even though we can’t see it that well.

Why Does Cannabis Love Blue Light?

It’s important to give your plants the blue light they need — especially in veg. With blue light — either from LED or MH lights — plants show robust lateral growth without extension. What’s more, plants grown with a spectrum that’s rich in blue have thicker, darker leaves than those grown without blue light, and that prepares them for a robust flowering period.

But why does blue light matter in the vegetative phase? And why does the reddish HPS spectrum work better for flowering? The answer comes from the natural seasons.

During the peak of summer, when plants are in veg, there’s a lot of blue light. As fall rolls around and it becomes time for reproductive growth, the light has a lot less blue light and more red. That’s because the blue light gets filtered out when the Earth tilts away from the sun and the light has to pass through more of the atmosphere. The atmosphere diffracts the blue, so there’s less for plants.

Grower Trick: Blue Light for Higher Cannabinoids

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Some growers have discovered a strange spectral trick to get higher terpene and cannabinoid levels. It goes against the natural seasonal light shift, but it can increase terpenes by a reported 50%.

At the end of flowering, in the final 3-7 days, growers return to a spectrum with lots of blue light. Sometimes, they switch bulbs from HPS back to MH (if their ballasts are compatible). Or — if they’re running tunable LEDs — they can simply change the settings on their controller.

It’s unclear why the change in the spectrum — which would be unnatural outdoors — produces more terpenes. Some growers think that it’s a stress response because blue light has more energy than other wavelengths. Other growers wonder if the plants “think” they’re back in the vegetative phase and they push more growth as a response. It’s as though the blue light sparks growth, except the growth, goes into the buds and overall terpene levels instead of foliage.

Either way, switching back to a bluish, vegetative-phase spectrum increases the quality of many varieties of cannabis. With more terpenes, the crop has a higher market value — and the grower has a higher reputation for producing a high-quality product.

If you’re interested in tunable LEDs or other LED spectrums that are custom-tailored to the needs of cannabis, check out Mitra — the only LED light in the market that has been created and perfected by cannabis growers. Or reach out to Heliospectra’s cannabis liaison, Ryan Wankle, a second-generation cannabis grower who can answer all your cultivation questions.

10 Mistakes to Avoid When Using LED Grow Lights

Grow lights are a great tool for making the growing process more efficient, but they can also be harmful to the plant if not used correctly. Here are 10 things you should avoid doing when using LED and other types of grow lights.

Source: Maximum Yield, May 31, 2019

For people who use cannabis derived products on a regular basis, it is very tempting to try growing the plant at home. The benefits are quite obvious: the cost is drastically lower and there aren’t any hassles related to the actual purchase of medical marijuana.
Many people all around the world grow cannabis at their homes, be it for recreational or medicinal purposes, and while some of them do quite well and manage to produce a good product, for others it doesn’t work so well – their plants wither quickly or produce insignificant yields.

These issues can be related to improper usage of lighting. (The same issues affect other types of plants as well.) Grow lights are a great tool for making the growing process more efficient, but they can also be harmful to the plant if not used correctly.

In this article, we’ll provide you with the 10 most common things you should pay attention to when using LED grow lights so you can grow healthy looking plants and avoid any unnecessary hassle. This information is extremely relevant to beginners.

Overheating the Plants
You will know the plant is taking too much heat if the leaves that are closest to the light start turning brownish. The first signs look like thin outlines on the outside of the leaves, so if you catch this quickly you will have a chance to avoid further damage. If some of the leaves start curling up, it might also be a sign that the plant is too close to the light. Good ventilation usually also helps with this issue.

Providing Insufficient Lighting
It is important to consider the scale of your operations. Think about how many plants you’re growing and how many LED lights you’ll need in order to illuminate them properly. You should also be aware of the luminosity of the lights you’re using. For example, a 200W LED light is said to be sufficient for a yield of about 100 grams. Make sure that you have enough lamps but still look for a good balance between providing sufficient lighting and not overdoing it.

Setting the Lamps at an Improper Distance
Overheating or insufficient lighting can result from having too many or not enough lights, but it can also result from placing the lights too close or too far from the plants. There is no universal rule for setting the distance but it’s recommended that LEDs are placed 12 to 18 inches away from the plants.

Using Inferior Products
Light is among the most vital factors to consider when growing plants because it triggers the photosynthesis process. If you’re using regular incandescent lights, you’re not very likely to grow strong and healthy plants. Therefore, for best results it is recommended that you use full spectrum LED grow lights. They are specifically designed for the purpose and have the feature to deliver light in the exact spectrum the plant needs.

Selecting the Wrong Light Spectrum
In order to grow efficiently, plants need different types of light for each growth stage. With full-spectrum LED lights this is easily achievable, but if you select the wrong setting, the plant will not develop well. You should also take into consideration the conditions in the room where you’re doing the growing. For example, plants benefit most from light in the blue spectrum when they’re in the vegetative stage of growth. That means that if you set the light to emit light in the red spectrum, you will only be hindering the plant’s growth.

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Using the Wrong Light Schedule
You should be careful not to leave the lights on all the time, or worse, the opposite – forget to turn them on. It might sound trivial but it’s quite easy to mess up the light schedule and even a minor change might have a negative impact the plant’s growth. Cannabis needs about 18-24 hours of light during the vegetative stage and 12 hours of light during the flowering stage.

Forgetting to Adjust the Lights
Many people forget to adjust the height of the lights as the plants grow bigger and end up with burnt leaves. Another important thing is to occasionally rotate the pots in order to prevent the plants from leaning towards the light too much.

Not Protecting and Maintaining the LED Lights
LED grow lights are your friend and an important investment, so you need to take proper care of them. They bring numerous benefits to the growing process and a little maintenance and preparation can save you a lot of trouble. It is recommended that you set up a power stabilizer and connect it to the lights in order to equalize the incoming voltage, thus protecting the chip inside the LEDs.

Overwatering When Switching from HIDs to LEDs
Regular HID lights produce a lot of heat and generate lots of infrared light. This dries out the plant and the soil and results in the need to water the plant more often. However, LED lights generate no infrared light and don’t emit nearly as much heat, so there is no need for abundant watering.

Not Considering the Other Factors
LED grow lights are a great aid when growing plants indoors but by themselves they cannot do much. In order to produce big and healthy yields there are a lot of factors that need to be considered – room temperature, airflow circulation, soil, nutrients, plant genetics, and many others things. Don’t just focus on a single part of the growing process. Instead, try to get an overall understanding of the whole chain and how everything is interconnected.

Grow lights are a vital piece of equipment that every aspiring grower should have. Although they are easy to use and set up, you should pay attention to this list of common mistakes and save yourself from headaches.

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.

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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.

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!