A plant cultivation system (100, 2100, 3100, 4100), comprising: (a) a frame (102 2102, 3102, 4102) having a frame upstream end (102a, 2102a, 4102a) and a frame downstream end (102b, 2102b, 4102b) spaced horizontally apart from the frame upstream end; (b) a plurality of vertically stacked conveyor assemblies (104, 2104, 3104, 4104) mounted to the frame, each conveyor assembly including at least one conveyor (106, 2106, 3106, 4106) extending between the frame upstream end and the frame downstream end along a conveyor axis (108, 2108, 4108); (c) a plurality of plant cultivation trays (110, 1110, 2110, 3110, 4110) supported on each conveyor for translation along a respective conveyor axis toward the frame downstream end, each plant cultivation tray including: a tray body (112, 1112) having a tray top (114, 1114) and a tray bottom (115, 1115) vertically opposite the tray top; a plurality of plant cavities (116, 1116, 2116) in the tray body and open to the tray top, the plant cavities for holding plants; and at least one tray vent (166, 1166) passing vertically through the tray body, the tray vent open to the tray top and the tray bottom for passing air vertically through the tray body to facilitate delivery of air to the plants from below; and (d) an air delivery ductwork (190, 3190, 4190) for delivering air to the plants, the air delivery ductwork including a plurality of first ports (192, 3192) above each plant cultivation tray for discharging air from the air delivery ductwork downwardly to deliver air to the plants from above, and a plurality of second ports (194, 3194) below each plant cultivation tray for discharging air from the air delivery ductwork upwardly to deliver air to the plants from below via the tray vents. (a) a frame (102 2102, 3102, 4102) having a frame upstream end (102a, 2102a, 4102a) and a frame downstream end (102b, 2102b, 4102b) spaced horizontally apart from the frame upstream end; (b) a plurality of vertically stacked conveyor assemblies (104, 2104, 3104, 4104) mounted to the frame, each conveyor assembly including at least one conveyor (106, 2106, 3106, 4106) extending between the frame upstream end and the frame downstream end along a conveyor axis (108, 2108, 4108); (c) a plurality of plant cultivation trays (110, 1110, 2110, 3110, 4110) supported on each conveyor for translation along a respective conveyor axis toward the frame downstream end, each plant cultivation tray including: a tray body (112, 1112) having a tray top (114, 1114) and a tray bottom (115, 1115) vertically opposite the tray top; a plurality of plant cavities (116, 1116, 2116) in the tray body and open to the tray top, the plant cavities for holding plants; and at least one tray vent (166, 1166) passing vertically through the tray body, the tray vent open to the tray top and the tray bottom for passing air vertically through the tray body to facilitate delivery of air to the plants from below; and (d) an air delivery ductwork (190, 3190, 4190) for delivering air to the plants, the air delivery ductwork including a plurality of first ports (192, 3192) above each plant cultivation tray for discharging air from the air delivery ductwork downwardly to deliver air to the plants from above, and a plurality of second ports (194, 3194) below each plant cultivation tray for discharging air from the air delivery ductwork upwardly to deliver air to the plants from below via the tray vents.