A seed-planting unit (10) of a growth medium has the form of a cylindrica! body that is intended to accommodate a number of seeds (16), The unit (10) is arranged to be handled in a stack (20) formed from several such cylindrical bodies and is intended to be planted in ground (60) for the germination and growth of the seeds with the aid of a planting arrangement (30), which has a planting channel (32) for the accommodation of the stack (20) in a manner that allows sliding and the release of one unit (10) at a time into the ground during planting.
