A seed planting apparatus has a first disc is rotatably disposed about a first axis which is substantially perpendicular to a line of travel. A following trenching device has a second disc rotatably attached along a second axis transverse to the line of travel but not parallel to the first axis. A third disc is rotatably attached along a third axis which is transverse to the line of travel but not parallel to either the first axis or the second axis. At least one of the first, second and third discs has a first side has an outer periphery and a second side has an outer periphery. The second side is spaced from the first side and has a larger diameter than the first side. A transition surface between the outer periphery of the first side and the outer periphery of the second side being annular and concave.