The present invention relates to a green roof module (1) for use in a level or pitched green roof, comprising a bottom element (2) and a side element (3) extending upwards from the bottom element and surrounding the bottom element for cooperating with the bottom element to form an interior space, the interior space being capable of retaining a growing medium for plants to grow in, the bottom element and side element forming a substantially square-formed roof module having four corners, characterised in that the side element comprises a tearable dividing line (4) extending in a substantially horizontal direction around the side element for dividing the side element in a non-removable part (3a) and a removable part (3b), the non-removable part being closer to the bottom element than the removable part, the removable part being capable of being partially or completely detached from the non-removable part by tearing. Furthermore, the present invention relates to a building comprising a plurality of green roof modules according the present invention and to a method of installing a plurality of green roof modules according the present invention.
