Seed screening comb for sowing machines (1) consisting of an accessory to be attached to all types of automatic sowing machines on the market, both flat and drum, in order to optimize efficiency and cost of the seeding operation in trays characterized in that it consists of a main body (2) and a sliding body (3) that moves with respect to the main body (2) by the action of a mechanism governed by a regulation wheel (6) the displacement being defined by a calibration vernier (14). Both the main body (2) and the sliding body (3) are provided with several blades (4) existing in the sliding body (3), as many blowers (5) as blades (4) fed by a blower tube (13) . The screening comb (1) has clamping means, in the form of domes (7), integral with the main body (2), with a locking wheel (9) for installation on a support bar attached to the screening machine . (Machine-translation by Google Translate, not legally binding)