The present invention relates to a seeding heart for a single-grain seeder, comprising - a seed disc (9) which can rotate in a direction of rotation (R) and has a plurality of seed holes (15) that are distributed concentrically to the seed disc (9) along at least one seed hole circle, and - at least one stirring shaft (18, 18') for moving the seed material, arranged in a receiving section (31) for receiving the seed material at the seed holes of the seed disc (9), characterized in that the stirring shaft (18, 18') has a modular exchangeable design. The invention further relates to a seeding heart and a single-grain seeder.
