The fertilizing apparatus comprises a diffusion member having a porous member associated with it to retain fertilizer inside a compartment defined by the diffusion member. The diffusion member provides a diffusion pathway that is protected from gravitational water flow and rapid temperature fluctuation. The compartment is filled with fertilizer and inserted into growth media adjacent a plant's root system so that the diffusion pathway is substantially occupied by the plant growth media. A plurality of diffusion members, each member having a different length, may be used to establish diffusion times for specific fertilizer formulations. The fertilizing apparatus can be adapted for use with a closed, insulated pallet system for producing container-grown plants.