How Far Should LED Grow Lights Be From Plants? This is actually one of the most common questions when getting ready to hang grow lights. However, the hang height is only a minor factor when planning lighting for a commercial space. In fact, the distance in which your grow lights are to the plants will have very little effect on the lighting of the crops receive due to the overlapping of the light beams. Once again, go back to the water analogy, and think of water pouring from the ceiling. The higher the water is dropping from would have little effect on how much was hitting the plants. The difficulty in deciding on how high to hang a light has more to deal with when considering the aisles and walls.
Via: https://www.canadagrowsindoors.ca/grow-lights/how-to-properly-hang-your-led-growlights-for-optimal-results/