Abstract: A planting substrate in the form of a soil-like mixture for flower boxes (10) is characterized in that the planting substrate is available filled in a bag (12), the bag skin of which consists of a plastic foil which has poor transparency and is water-permeable from the outside, and the shape of the bag (12) is or can be adapted to the inner cross-section of the flower box (10) in such a manner that the bag (12) has room in the flower box (10) in terms of size.