A hollow upper deck panel for a plastic pallet has a solid top surface and is produced by forming a tubular hot plastic parison and directing the parison between blow mold sections to form upper and lower sheets for the deck panel. The lower sheet is blow molded by pressured air within the parison into a mold section to form spaced inverted U-shaped open ribs projecting upwardly and with top portions fused to the upper sheet. The upper sheet is blow molded by the air around retractable blades to form spaced closed double wall ribs projecting downwardly between the open ribs and have bottom portions fused to the lower sheet. The closed double wall ribs extend transversely to the open ribs and have end portions fused to the open ribs. The support structure for the upper deck panel defines spaces for receiving parallel spaced forks of a forklift truck.