Abstract: The invention is directed to an LED lighting system for use in promoting biological growth. In one embodiment, the lighting system includes a plurality of “N” bar-like LED modules. Each of the LED modules is of the same length and the length is determined by the number of same-length LED circuit boards supported in an end-to-end manner by the LED module. The lighting system also includes a pair of bar-like end modules adapted to rigidly engage no more than “N” LED modules to realize a module structure in which the LED modules and the end modules respectively form the rungs and rails of a ladder-like structure. The lighting system is readily scalable in the length of the of the LED modules, as determined by the number of LED circuit boards supported, and in the number of LED modules supported by the pair of end modules.