Plant container irrigation apparatus (10) includes a master controller (12) for controlling irrigation of a plant container (14). The apparatus (10) includes an irrigation liquid transport arrangement (16) for transporting irrigation liquid (18) from an irrigation liquid supply (20) to, in use, the plant container (14). The transport arrangement (16) includes a flow controller (22) for controlling the flow of the irrigation liquid (18) to the plant container (14), the flow controller (22) being movable between a flow condition, in which the flow controller (22) permits the irrigation liquid (18) to flow to the plant container (14), and a non-flow condition, in which the flow controller (22) does not permit flow of the irrigation liquid (18) to the plant container (14). The apparatus (10) includes a run-off detector (24) which, in use, detects irrigation liquid run-off (26) from the plant container (14) and provides a run-off detection signal (28) to the master controller (12). The master controller (12) is arranged so that receipt of the run-off detection signal (28) causes the flow controller (22) to move from the flow condition to the non-flow condition.