Slab of potting compost for growing plants

Slab of potting compost for creating living walls or planted roofs characterized in that it comprises an inextensile sheet equipped with means for making it permeable to water and to air, an extensile fabric made up of fibres, spaced apart, a potting compost in which plants can be grown, in that the fabric is bonded to one face of the sheet, in that the spaces between the fibres are filled with the potting compost and in that a binder capable of encouraging the formation of clumps of compost, of a size larger than the spaces between the fibres, is mixed in with the compost.