A propagation tray for growing a plurality of plug plants in bounded transplantable growing media has two spaced apart aperture plates. The plug plants are held loosely in the apertures in a top plate while retained at the apertures in the bottom plate over air cells associated with and under the apertures in the bottom plate. The air cells provide a volume into which roots from the plug plant may grow, and the air cells have at least one port for drainage and/or ventilation and toward which roots are guided to be air pruned. The propagation tray maximizes air flow around the plug for air pruning of roots, while minimizing contact of the plug with the structures on the tray to reduce the formation of root defects.