Solis are engineered growing mediums for extensive and intensive green roofs. The composition of the medium will vary according to the needs of each project. Growing media particles can range from very fine to coarse. Particles that are too large may not retain enough water and/or nutrients to sustain plant life; particles that are too fine may clog filter fabrics and drainage layers or become compacted, either of which will inhibit drainage and damage the long-term health of plants.