The invention provides a seed sowing coulter implement comprising a vertical cutting blade in the form of a rotatable disc disposed in the line of travel and having a peripheral cutting edge part arranged to penetrate and slit the ground as the implement is moved along, a pair of detachably mounted coulter tip part disposed adjacent one side of the blade for location and operation solely below ground level, means for determining the depth of cut of the blade and location of the coulter tip parts below ground level, and a seed duct member provided in juxtaposition with the blade and a support for the coulter tip parts and arranged to feed seeds from a supply source into a passage formed by the coulter tip parts at a point close to such part and behind the leading edges thereof.