A distribution box for a single-seeder including a disc including radial grooves that are regularly spaced apart and open on a periphery of the disc, the disc being rotatably mounted on a horizontal axis and separating a seed reservoir from a suction device such that seeds are picked up from the reservoir by the disc via air flow by negative pressure and are held over at least part of their angular travel until they are expelled from a discharge opening. Each groove includes a suction hole smaller than a size of the seeds to be distributed, the suction hole emerging on a channel with a width smaller than the diameter of the suction hole, the channel being open up to the periphery of the disc. A single-seeder can include at least one distribution box.