An air cooled double ended high pressure sodium lamp fixture for growing plants in confined indoor spaces. The fixture seals the lamp and heat generated by the same to a reflector interior. Flow disruptors create turbulence in a cooling chamber thereby enhancing thermal transfer into a cooling air stream that flows over and around the reflector's exterior side thereby convectively cooling the lamp using the reflector as a heat sink. The lamp is effectively maintained at operational temperatures and the fixture housing is insulated from the hotter reflector by a gap of moving cooling air, allowing use of the double ended HPS lamp in confined indoor growing spaces.