A lighting system for growing of plants, comprising a lighting arrangement arranged in connection with the plants, which includes several electric lamps, and a cooling arrangement at least for cooling down light producing components of the lamps due to heat being generated by the same while producing light. The lighting system is arranged to be utilized in connection with a cooling arrangement, being separate with respect to the lamps of the lighting arrangement, and comprising a cooling structure, being mounted in connection with the plants. A lamp comprises a mechanical fastening frame, being coupled in a built-in manner in connection with its one or more electric components in order to attach the lamp externally against an outer surface of the cooling structure, for cooling down the lamp conductively through the cooling structure.