The effects of environmental factors on seed germination and seedling emergence of Oriental mustard were studied in laboratory and field experiments. Seed germination was stimulated by light; however, some germination occurred in the dark. In light/dark, potassium nitrate at 0.02 M stimulated germination of 1-mo-old seed to a maximum level of 45% as compared with the control (18%). Oriental mustard germination was inhibited by high levels of salt and osmotic stress. Seed germination was greater than 50% over a pH range of 4 to 10. Seedling emergence of 4- to 5-mo-old seeds was highest when present on the soil surface (70%) but declined with depth, and no seedlings emerged from a soil depth of 10 mm. In the field, seedling emergence was greater under no-till than minimum tillage systems.