How to design a simple rooftop garden?

[remnant]

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.

 

[sixxup]

First you'll have to make sure that there are no leakages to the rooms below. You can use super glue to stick the polythene together. You'll also need an access route which is safe. You'll then have to connect water pipes hence making it easier for you to water your crops.

 

[marlingardener]

Fill a bag with soil, dampen it as if there was a plant in it, and weigh it. Then multiply the one bag's weight by the number of bags you plan to have. Will your roof support that weight?
If you are worried about drainage, set the bags in a long tubular basin (think a huge gutter) and drain the water off the roof to prevent damage.
Also, have you taken the temperature on the roof on a warm sunny day? Iron reflects heat, enough so that the direct heat and reflected heat could cook your plants.