pakistan,
Asia/Pacific Region 
hi this me Noor please send me tips of roof gardening that how can we safely planted plants on roof with damaging the roof.
20 Oct, 2012
Answers
You would have to use either pots / containers or raised bed filled with soil / compost.
Then you are faced with your roof construction!
Pots & Beds can get quite heavy particularly when wet, and most roofs are not designed for point loads such as produced by these containers!
So basically the strength of your roof could be your biggest problem!
What type of roof construction do you have?
20 Oct, 2012
Previous question
« Can you grow an Acer Platanoides Crimson successsfully in a container/pot ?
You have to have a reinforced roof, Noorjournalist - you must get a builder or preferably a surveyor to tell you whether or not your roof is sufficiently weight bearing for this purpose.
20 Oct, 2012