A light assembly (10) for installation in a greenhouse comprises a light unit (30) and at least one light fixture (20) mounted thereto. The light unit (30) comprises a light unit body comprising a light mounting structure (200), and a plurality of light sources mounted to the light unit body along a row. The light fixture (20) comprises a light fixture body comprising a light mounting structure (100) for mounting a light unit (30) thereto with thermal connection therebetween, a first passage (140) comprising an entry port (142) and an exit port (144) for a cooling fluid to circulate to dissipate heat conducted from the light unit (30) into the light fixture (20), a second passage (150) comprising an entry port (152) for receiving vaporizable compounds, and vaporization ports (160) fluidly connected to the second passage (150).
