In my area, almost nobody has converted their roof into a garden despite the aesthetic potential of the initiative. In addition, one can grow vegetables there. My idea of a rooftop garden is a number of polythene bags or sacks with a wide mouth which are then filled with rich soil and then placed on the roof. But these would require holes for drainage which can ruin a corrugated iron roof. Any alternative ideas or designs are welcome, those which can work on a corrugated iron roof.