A container for propagating or growing plants is configured to receive a substrate for propagating plants and comprises a drain hole, an inclined side wall, and a plurality of ribs positioned on the side wall and extending into the container. At least two ribs are arranged close to and parallel to one another, defining a channel therebetween through which air may flow, in use, when the container contains a substrate. In a plant tray comprising an array of cells, at least one cell comprises a rim, arranged around the drain hole on the underside of the cell, in which a thickness of the rim is greater than a thickness of the side wall. A plant tray comprising an array of cells having octagonal cell openings comprises a plurality of vents arranged between the cells and configured to allow air to flow through the tray top. A plant tray comprising vents in the tray top comprises vent rims arranged around the circumferences of the vents, the vent rims being configured to project downwards from the tray top.
