There’s no “set” distance LED lights should be from the tops of your plants, but a good rule of thumb is 12-18+ inches.（30.44~45.67cm）
Each model is different based on the size of its bulbs and the lenses used to reflect light down. It’s important to ask the manufacturer how far to keep LEDs from your plants. Smaller LEDs with 1W chips almost always need to be kept at least 12″ away. However, most LEDs with 3W chips or bigger need to be kept 18″ away or more to get the best results and prevent light burn. Check with the manufacturer to figure out the right distance for your particular model of LED grow light
If just the tops of your plants are showing symptoms, chances are that your LED lights are too close.
