A lighting array for providing artificial light include a square or rectangular frame on which a plurality of chip on board (COB) units are mounted. Each COB units includes a light emitting diode (LED) element. The COB units are mounted in an arrangement of columns and rows, where there are an odd number of columns defined, and COB units on odd numbered columns do not share rows with COB units positioned on even numbered columns. The arrangement achieves a greater uniformity of light intensity over a given growing area compared to conventional lighting systems, at similar light output levels.
