Snoop Dream Bag Seed

Each LED is different and there is no standard distance like with other light sources (like HID, T5, etc). The answer you are looking for depends on what kind of diodes your model uses (1W, 3W, 5W, 10W) and how hard they are driven (how much actual power are passed through them). The best answer would be to look on the manufacturer recommended distance. But if you can't find it, I would start at 18 inches (45 cm) and see how your plant reacts, does it stretch? Get it closer, day 12 inches (30 cm); Does it show symptoms of heat stress? Try 24 inches (60 cm). What you can do also is try different distances with the back of your hand, if it is comfortable for you, it is ok for the plants and if it is too hot for the back of your hand, then it's too hot for your plants.