A device and method for altering biochrome ratios in plant leaves is provided. The device and method generally include a a light source; and means of directing the light source to deliver an altering spectrum to a group of cells. The altering spectrum alters the biochrome content of a group of cells to produce a contrasting color that creates a desired pattern on a leaf. The device may include a first light source that emits a main growth spectrum, a second light source that emits an altering spectrum; and means of directing the first and second light source to a group of cells, wherein the altering spectrum alters the biochrome content of a group of cells to create a desired pattern on a leaf. Methods of altering the biochrome ratio in a group of cells on a leaf generally involve aligning a surface of a leaf with a light source, activating the light source to produce an altering spectrum, and directing the altering spectrum towards the leaf to create a pattern, wherein cells of the leaf exposed to the altering spectrum exhibit a desired pattern.