6 common mistakes when using LED growing lights

Before, most growers used HID lights for their growroom but good results. However, LED lights are slowly taking over all the growroom around the world. The LED revolution has become very populair in the last few years as the low electricity costs, long lifespan and perfect colour spectrums made growing more affordable and efficient. Many growers are taking advantage of these benefits producing amazing results.

Yet, starting with a LED grow isn’t that easy. Many people make mistakes with choosing the right light and how it’s being used! So let’s take a look at the most common mistakes with LED growing lights:

1. Choosing the wrong type of LED’s

The colour spectrum of a LED light is very important when it comes to growing cannabis. The right combination of blue, red and white lights will shine a bright purple colour that’s perfect for the growth of a plant. Most LED’s are being sold as “full spectrum” lights which means they can be used for the vegging and flowering phase of your plant.

Other models offer a switch so they can be adjusted to “veg mode” or “flower mode”. This means you can turn on certain coloured leds that are more suitable for the vegging phase (bluish light perfect for fast growth) or flowering (Purple/red light perfect for bud development). Before buying a LED, think about this. Do you want a simple “full spectrum” light, or one with a switch to focus on a certain phase?

2. Using low-quality LED’s

A big disadvantage for High quality LED’s (compared to other lights) is that they are quite expensive. Many people that want to be part of the LED revolution, don’t have the budget for a high quality, full spectrum light so they end up looking for cheaper LED growing lights.

The problem with this is that the market is full of low quality lights that are actually way to weak for cannabis plants. They are often manufactured in China or other countries overseas and they claim that they produce more light as they actually do resulting in failed yields and lot’s of frustration. Next to that they can cause a serious fire hazard if they don’t meet strict safety requirements.

We recommend to spend a little more on a proper LED light and really offer your plants what they need. Avoid chinese wholesale websites and visit a legit local growshop and aks of details/help. Another way to research the quality of a light is by looking up some grow reports on the internet, then you can compare their type of lights and the results they produce.

3. Setting up the lights on the wrong height

Many growers that are switching to LED are facing problems with the height of their LED panels. The main reason for this is that most growers are used to other lights like HID’s. These emit lots of heat and need to be installed high enough not to damage your plants. So it often happens that these growers are being too cautious and hang their LED panels too high to fully take advantage of all light intensity. LED lights won’t emit any heat it all, so don’t worry about burning your plants!

If you hang your LED’s too high, your plants will over-stretch to reach a higher light intensity.

On the other hand, there are growers that are aware of this and they want to hang their LED’s as close as possible. However this could also cause major problems to the plant. There are 2 reasons why: 

  • Every LED has it’s own colour. Multiple LED’s combined on a panel will provide a good colour spectrum to grow plants. If you hang that panel to close to your plants, it could happen that some  colours/LED’s are being blocked from reaching the plant. This results in a wrong colour spectrum and could stress out your plants.
  •  With powerfull LED panels, it’s possible that your plant get’s too much light it can handle. We call this “over-lighting”. This will result in lots of stress, burned leaves and bleaching of bud and leafs. Make sure to avoid this at any time!

But what is the right height?

Well it’s hard to give a specific answer to this as the optimal distance during both growing phases, really depends on your LED. All brands and types of LED’s can vary slightly from each other which could affect the distance from your plants. The first thing to find this out is by reading the manual of your light., sometimes they provide info about the height/distance of your LED’s.

If they don’t, check out the internet for grow-reports or other information about your specific type of light. If you still can’t find any info, try hangin them at +-40CM from the canopy* of your plants and see how that works out. During the flowering phase, you could even lower them a little more.

*Canopy: The upper most layer of branches/leafs (when talking about cannabis)

When adjusting or trying new heights, always keep a close look at the plants and how they react. Keep an eye out for dry, curled leafs or signs of bleaching!

4. Overwatering your plants

Another big problem that many LED growers face is overwatering their plants. Compared to HID’s (that most growers are used to), LED’s won’t emit that much heat. So the soil in a HID growroom will dry up way faster then soil in a LED growroom. This reduction of heat means that you don’t have to water your plants that often. Especially new users of LED should adjust their watering schedule to be optimal for a LED grow. Overwatering is very common and could lead to multiple pests and damaged (drowned) roots. Always check and feel if the soil is dry enough before watering, very important! 

5. Not giving your plants enough light/wrong info

A big and common issue with these cheaper “beginner” LED manufacturers is that they use multipe details, numbers and specs to intentionally confuse the buyer (for example: Wattage). At first, you might think these details matter and give you a honest description about the light. However when using LED’s, the wattage doesn’t say anything about the strength/amount of light your light is emitting. It only shows how much electricity is needed to produce the light.

When using LED you need to pay attention to Lumens instead of Watt’s

So even with a high wattage, your light might still be weak and have a poor spread. This means that lower parts of the plant won’t get enough light which is a bad sign! Don’t become a victim and always check out the reviews/experiences from other users before buying a vegetative and bloom phase specific light.

Problems with the amount of light mostly happens when growing multiple plants instead of one. Let’s say you buy a 300W single LED light panel. This could work great for +- 2 plants in a small tent but it won’t cover a bigger space with multiple plants. So always research what you need for your growing area and check if the seller/manufacturer’s recommendations are right. You could also check grow reports to see how much light other people need for a succesfull grow.

6. Providing the wrong light schedule

There are 2 type of cannabis plants available that each have a different reaction on the amount of light-hours it gets: Autoflower strains and Photoperiod strains. It’s up to you which one to choose but you need to keep some things in mind!

Autoflowers strains

An autoflower strain is relatively easy to grow compared to Photoperiod plants. You don’t have to do much about the light schedule because you can give them 18-24 hours of light from germination untill harvest. The unique feature they have is that they start their flower period automatically after a few weeks. This makes them very convenient in certain circumstances.

Want to learn more about autoflowers and their characteristics? 

Photoperiod strains

Photoperiod strains work in a different way. In the first phase (vegetative), they are grown under +-18 hours of light. This means their “nights” are relatively short (like summer nights). Once they reached the desired height, you need to put them in the flower phase manually. The only way to do this is by lowering the amount of light hours (creating shorter days and longer nights, like late summer days).

Cannabis plants notice this and think the summer is over and cold and wet days (Fall) are comming. They want to be riped and ready before that happens so it’s in their nature to start flowering as soon as the light hours decrease.

Experienced growers will know these details. However for beginners this is important information and something to think about before buying seeds!

Do you have more tips/tricks to help people with their LED light problems? Leave them in a comment below!


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