A green roof modular system includes at least four planter modules each including a planter including a bottom wall and a plurality of sidewalls that cooperate with the bottom wall to form an interior space, and a biodegradable insert including a plurality of sidewalls that cooperate with one another to form an interior space, wherein the insert is adapted to retain a plant matter in the interior space of the insert, the plurality of sidewalls of the insert extending above the plurality of sidewalls of the planter, and wherein the plurality of the sidewalls of the insert are adapted to retain a plant matter that extends above the plurality of sidewalls of the planter, such that one of the planter modules abuts each of the remaining three planter modules and substantially no gap exists between the abutting planter modules in plan view.
