A conveyor system (4, 5) moves vertical poles (2) in an agricultural facility between a growing area (20) and a workstation (W). Each pole carries plant growing containers (3) at multiple levels (H1-H9). An irrigation reservoir (30) may be mounted on each pole. Irrigation lines (31-33) from the reservoir may be individually metered (35) at each level to compensate for differing water pressure with height. Sensors (40) in the reservoir and at each level of the poles may provide a controller (36) with data input. The controller may impose different growing conditions in different areas of the facility, including vertically different grow areas (20A, 20B), and controls pole movements and locations selectively to provide a sequence of poles at the workstation ready to harvest on a demand schedule. The workstation may have multiple heights (W1, W2, W3) for tall poles that increase plant density per facility footprint.