growing weed with led

Using LED Grow Lights: 6 Mistakes to Avoid?

Whether you are new to growing cannabis or just new to growing with LEDs, mistakes can happen! Find out what you should avoid in order to grow top-tier cannabis under LED lights!


Growing great cannabis is not really difficult—at least in theory. Get yourself some quality cannabis seeds, good soil, proper containers, and you’re already off to a good start. However, if there’s one factor that’s especially crucial to developing superb cannabis, it’s light—a lot of it. Indeed, cannabis plants require more light than most other plants, and they optimise performance if light exposure is significant and consistent. As such, you really don’t want to skimp when it comes to your grow lights.

In the past, weed cultivators largely used HID lights—with MH (metal halide) lights used for vegging and HPS (high pressure sodium) lights employed for flowering. HID lights are still viable, and they have a great track record amongst home and commercial growers alike. That said, LEDs are exponentially taking over grow rooms around the world. Why? Compared to HID, LEDs have some convincing advantages: They use (a lot) less electricity, allowing you to save money over time and reduce the footprint you leave on the environment. They also emit less heat, which can be a big advantage, especially in small grow setups. Lastly, LEDs have recently become more affordable as the tech has become widespread, allowing home growers an opportunity to benefit from this unique and powerful lighting system.

Yet, even the fanciest LED lights cannot prevent growers from making mistakes in their grow. Let’s delve into some common errors, slips, and faux pas to avoid when growing cannabis with LEDs.


This is probably the most common mistake that inexperienced growers make upon just starting out with LEDs. Since HID lights emit a lot of heat, out-of-the-loop growers might be overly cautious with their LEDs, placing them too far away; alternatively, those aware of the benefits of LEDs might get cocky and place the lights super close. If you hang your LEDs too far away, there’s a good chance your plants will over-stretch in an effort to reach closer to the light. If, on the other hand, you place your LEDs too close to your cannabis plants, this can stress the plants more than they can comfortably handle, causing burning and bleaching of the foliage and buds.

So, what is the ideal distance between your grow lights and your plant canopy? Unfortunately, there is no standard, since the best distance during the vegetative and bloom phases of your cannabis will depend on your specific LED. Each type can vary slightly, therefore affecting the final distance they should be from your plants. The first port of call is to check the manual you received with your LEDs for any information on recommended distance. If you can’t find it there, check out the manufacturer’s website. If, for whatever reason, you cannot find any information, you can keep your LEDs somewhere between 30–45cm from the canopy—around 45cm during veg, then a little closer when your plants are flowering.

When adjusting the height of your LEDs for peak performance, keep an eye out for any oddities. Dry, curled, brown, or bleached leaves signal too much light, calling for your LEDs to be raised higher.


Because good ol’ HID lights emit a lot more heat than LEDs, soil normally dries out quicker when utilising the former. Once growers make the switch, however, they often forget to take this into account. Given the significant reduction in heat, it’s likely your plants will need less frequent watering. So adjust your schedule accordingly when using LEDs, especially if you’re new to it. Overwatering is a common and sometimes serious error beginners make that paves the way for a host of pests and diseases to take hold. So this is really important to keep an eye out for. When in doubt, let your soil dry out—then you can water again.


Most LED grow lights you can find today are “full spectrum” lights, which is sort of a buzzword that means you can use them for vegging and flowering. But there are also models outfitted with a switch that allows you to change the light spectrum according to the phase. Moreover, some LEDs are made only for veg—emitting a bluish light that supports fast and vigorous growth—while others are made for bloom, giving off a reddish light to support bud development. So, before you get an LED light, make sure it’s the right type. For most growers, a full spectrum LED is likely what you’ll want.


If there’s one drawback to LED lights in comparison to HID, it’s that a quality LED is significantly more expensive outright . Not everyone has the cash upfront for a high-quality, full spectrum LED, so they look for ways to save money while still benefitting from the technology. The problem is, there are now tons of low-quality LEDs available on the internet to satisfy this very issue—and these manufacturers are not prioritising quality. These cheap LED lights are often manufactured overseas, and claim to provide more light than they’re actually capable of. Some of these lights are only able to grow one plant (if you’re lucky), and not much more. Low-quality LEDs can also be dangerous to operate if they’re made in a country that has less strict requirements on electrical safety.

Lastly, if you get a cheap LED from overseas and you run into trouble, you will likely have a hard time with warranties and returns. As almost nothing is as important as your lights when growing cannabis indoors, it’s simply not smart to cut corners here. By spending a bit more on a quality LED, you and your plants will be so much happier. Plus, high-quality LEDs are much less expensive to run than HIDs, so you’ll surely save some serious cash on your energy bill over time!


The issue with many of those cheap “beginner LEDs” is that some manufacturers intentionally confuse the grower with specs and numbers, such as wattage. This seems fine, except that, with LED lights, wattage doesn’t really say how much light the LED is emitting; it says how much energy is required to produce the light. Instead, we’re measuring in lumens—the amount of light actually emitted. So, regardless of how high the wattage is, the light could still have a poor spread and/or doesn’t penetrate the canopy well. In other words, don’t fall victim to misleading information, and consider the source of your product.

Providing your plants with enough light can become an issue if you want to grow more than one. 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. You can also look for reviews and user reports on grow forums if you want to know more about using a particular LED.


At most high-quality seed shops, you can get autoflowering cannabis seeds and feminized photoperiod cannabis seeds. Autoflowering strains are relatively easy to grow, especially when it comes to lighting: You can just keep them under an 18–24-hour daily light schedule from the moment you plant your seeds up until harvest. They flower automatically after a few weeks of growth, which makes them very convenient.

Feminized (photoperiod) strains, on the other hand, are typically grown under 18–24 hours of light in the vegetative stage, then under 12 hours of light and 12 hours of darkness to initiate and sustain flowering. This shouldn’t be a problem, as most growers will set their lights on a timer for this very purpose. Then again, for someone who’s just starting out, they might not feel confident tailoring different light cycles and spectrums, especially if their setup doesn’t utilise full spectrum lights. It’s certainly not impossible for beginner growers to swiftly get the hang of maintaining proper light schedules, but sometimes the new tech of LEDs can lead people to make silly mistakes. In that case, you may wonder why your plant is reaching gigantic heights, but won’t grow you any buds!


For more tips on growing with LEDs, check out our blog on how to make the most of your LEDs. Lastly, keep in mind that even the most advanced LED system doesn’t just magically grow good weed. So always be sure to provide your plants with the necessary water, nutrients, substrate, and all the other great things it needs. With patience, care, and some powerful LEDs, your plants will reward you with fat, resinous buds come harvest!

LED lights have become increasingly popular in the cannabis grow community. If you plan to grow weed under LED lights, avoid making these 6 common mistakes!

What you should know about growing weed with LED lights

When grown indoors, cannabis plants need a lot of light, which is the most important feature compared to other plants. “A lot” means: in order for a plant to exploit its full genetic potential, more light is needed than is available in many parts of the northern hemisphere. In the UK, for example, both the light intensity and the light duration are lower than in southern Spain or Morocco. That’s why cannabis plants thrive much better there. Indoor growers therefore often prefer growing weed with LED lights.

The advantages of LEDs in cannabis cultivation

The number of cannabis growers keeps increasing, the quality of plants has never been better than before, so the trend has turned away from HPS lights in favour of LEDs. So what are the advantages?

1. Saving money

First of all, the energy savings are enormous. If you use an LED grow lamp for the same purposes as an HPS lamp, you can save about 40 percent of the energy consumption with the LED light. LEDs also last much longer than other light sources. You can expect between 50,000 and 60,000 operating hours for an LED lamp, compared to 2,000 to 3,000 hours with an HPS light. This is because LED lights have no filament to glow.

For many years, LED grow lights resulted in the same yields as their high-pressure sodium counterparts but technology has considerably advanced in the last few years. The advantage of LEDs is that they operate at a much lower temperature, consuming less than half the electricity and giving more control over the plants. With LED lights, cannabis plants grown indoors will have a wonderful fragrance and exceptional flavour. The most efficient LED lights reduce power consumption by 60 percent.

2. Less space needed

LED grow lamps take up less space, shine faster, are more durable and more impact-resistant than HPS lamps. They also have much less heat generation, reducing the need to keep your grow room fresh, which significantly reduces the risk of fire. HPS grow lamps get very hot, but high-quality LED lamps still feel cool even after several hours of use.

3. Fewer reflectors needed

LED grow lamps focus the light with lenses so that fewer reflectors are needed as with NDL grow lamps, which scatter the light without focusing and therefore require external focusing. HPS lamps require approx. 100 to 150 watts more power than LED bulbs because power management is integrated into the LED lamps. HPS lamps require external ballasts which also require electricity and thus increase consumption.

4. No warming up time

In contrast to HPS lamps, which take a while to warm up before they light up completely, LED lamps switch on and off immediately. LED grow lamps can even be easily dimmed. LED lamps classified as Class 1 are considered safer plant light. This is also because they do not contain mercury like some other lamps, such as compact fluorescent lamps.

5. Deter pests and bacteria

LEDs also have the ability to deter pests and bacteria.

6. Disadvantages of LED lights

Although the light spectrum of new LED grow lamps is very well suited for the entire life cycle of a cannabis plant, certain NDL lamps are still somewhat better. However, this difference is no longer large and is therefore negligible for most growers. There are huge advantages to growing with LEDs over high-pressure HPS sodium bulbs, fluorescents and plasma lamps. LEDs work very well, use little electricity and produce healthier plants with great taste and aroma.

Of course there are also disadvantages associated with the use of LED. When using LED grow lamps, precise management is required. In addition, LED lamps have higher purchase costs. Apart from that, they are cheaper over a longer period.

Invest in LED lighting for growing cannabis

After selecting the marijuana seeds for your grow, lighting is the next important component of indoor growing. Investing in high-end G8 LED type lamps will pay dividends in the years to follow. You will be able to save money and enjoy impressive crops.

It’s not surprising that LED grow lights are predicted to become increasingly important to indoor weed growers.

Photosynthetic Photon Flux (PPF)

The PAR value describes the flux of photosynthetic photons, measured in micromoles (μmoles) per square metre per second. Photosynthesis is the natural process by which plants use light to synthesize food from carbon dioxide and water, leading to plant growth.
The number of photons of light sets the photosynthetic photon flux. Natural sunlight, for example, has a PAR value of 1200-1600 micromoles (μmoles) when the sun is directly overhead.

Efficient grow lights will have PAR values that range between 800 and 1600 μmol. Using lighting with higher PAR values ​​can be counterproductive and cause stunted plant growth. The G8LED 600 Watt Veg / Flower lamp has a PAR value of 1480μmoles

LEDs that use most of the light spectrum

As the use of LEDs is aimed at reducing energy consumption, it is beneficial to grow weed with an ultra efficient grow light that optimises photosynthesis.

The best quality LED grow lights utilise six to nine varying wavelengths of the light spectrum. If there are fewer than six wavelengths, the light will not be sufficient for robust and healthy growth.

If there are over nine wavelengths, the light is comparatively inefficient as it emits parts of the light spectrum that plants don’t require —this waste leads to lower yields and excess heat.

LEDs emit ultraviolet light, which traditional bulbs do not. LED lights that emit ultraviolet light have the extra benefit of encouraging the formation of resin and also help repel pests in the grow tent. Cultivating weed with a grow light that has UV diodes will increase your grow volume.

The advantages of growing weed with LED lights are huge. Curious why growers prefer LED? Check it out in this blog!