The effects of petroleum mulches on the emergence and yield of tomatoes were studied at the Farmington Field Station, Greenville Field Station, North Logan, and the greenhouse. The mulches were applied as surface overlays above the seed or incorporating before plantin. Seedling emergence and yields were measured. Data recorded from trials conducted under cool weather conditions indicated that petroleum mulch overlays can be effective in increasing seedling emergence. The increased seedling emergence with petroleum mulch is due to increased soil temperature , less moisture loss from the surface, and a minimum of soil crust formation.