A plant propagation tray includes a substantially rectangular tray having a perforated bottom formed with a plurality of substantially parallel spaced apart raised inverted V structures or ridges which extend across substantially the entire bottom of the tray from one side of the tray to an opposite parallel side of the tray. According to one embodiment, the tray is provided with side walls for use alone or in a flat. According to another embodiment, the tray is free of side walls and is used in conjunction with a flat, a greenhouse bench, or a container having side walls. The horizontal distance between the ridges is preferably substantially equal to the vertical height of the soil which will be placed on the tray and the vertical height of the ridges is preferably approximately 15-40% of the vertical height of the soil which will be placed on the tray. The trays can be made to accommodate many different sized plants. The trays can be inexpensively manufactured from vacuum-formed thermoplastic. The trays which are provided with side walls can be nested to conserve space during storage and shipping prior to use. Moreover, the trays without side walls may be easily overlapped to fit existing installations such as greenhouse benches.