A vertically disposed HID lamp fixture for growing plants, which includes a housing having an interior, an exterior, a top hole, and a lower lip defining a light opening towards the plants, further including an inlet duct and outlet duct for the forced air cooling embodiment, a socket tower having an upper flange and a lower flange, the upper flange affixed around the perimeter of the top hole securing the socket tower to the housing, a reflector having an aperture, the lower flange affixed around the perimeter of the aperture suspends the reflector within the housing such that an isolation chamber is formed between the exterior side of the reflector and the interior of the housing, a HID lamp removably engages within said socket tower longitudinally extending substantially downward and through said aperture vertically disposed above said light opening sealed by a compressively held glass sheet.