Keep a High Intensity Discharge (HID) bulb about 30" - 36" above the top of your plants. This is an average distance...lower wattage bulbs may be placed closer, while higher wattage bulbs may need to be placed further away. Higher wattage bulbs provide more intense light for large growing areas. Lower wattage systems are used for smaller garden areas. Note: the height of the reflector / fixture above the plants will also affect coverage area. Average coverage area by wattage: W = AV [Watts equals Amperage (Amps) times Voltage] |