LEDs can cause cannabis leaves to look discoloured, even if nutrient levels are fine. This doesn't always mean that there is something wrong with your plants, but if you're noticing discoloured leaves in spots closest to the lights, it may be an indication that you're experiencing light burn. Most modern LED grow lights need to be kept at least 12-18" away from your plants to prevent light burn.You want your plants to get as much light as they can, so you generally want to keep your lights hung close to your plants, but just not too close. Keeping your lights 12-18" away will require adjustments as your plants grow. JUMP TO LED LIGHTING