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.
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, usually closer to 18"..
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.
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.
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.