Sowing heart for a single-grain sowing machine comprising: a sowing disk rotatable in a rotational direction R, the sowing disk having at least two sowing hole series, arranged concentrically to the sowing disk, with sowing holes, a receiving area for receiving seed at the sowing holes and a dispensing area for dispensing seed, in front of the dispensing area, a wiping device is provided for singulating seed at the sowing holes during the operation of the sowing heart, which has a first wiping element for the first sowing hole series and a second wiping element for the second sowing hole series, whereby the wiping elements are coupled and are designed to be adjustable with respect to one another. In addition, the invention relates to a single-grain sowing machine with a considerable number of sowing aggregates, in each case with an above-mentioned sowing heart and a corresponding wiping device.