Plant propagation tray assembly

A propagation tray assembly comprises a support tray and a plurality of seedling holder inserts 4 locatable in the support tray in side by side relationship, each insert comprising a row of cells 6, each cell having an open top and an open side to facilitate inspection and removal of the contents thereof when the respective insert is removed from the support tray, wherein the open sides of each cell in a first insert are closed by the adjacent insert when the inserts are located in the support tray in side by side relationship. The first 10, second 12 and third 14 walls maybe tapered towards a base wall 16 to allow the inserts to be stacked. The first walls of each insert may comprise a tapered first wall portion defining a rear wall on the cell and a substantially vertical second wall depending from an upper edge of the first wall portion.