While HPS lights should be placed between 2 and 6 feet (0.5-2 m) away from your crops, LED grow lights should be placed at least 12 to 18 inches (30 to 46 cm) away. However, the power of every light may vary significantly. Reading the instructions in case they suggest an alternative placement.
After you install the grow light, you should always pay attention to your plants. If your plants are coming too close to the light source as they get taller, you may need to move the light farther. Place your grow light farther away if you’re unsure.