This Old House looks at GreenGrid, a green roof system that they suggest can be done do-it-yourself. The GreenGrid system is based on a 2 foot by 2 foot plastic container with dimples on the bottom to provide drainage. The GreenGrid site doesn't particularly note that it is for DIYers, so we might point out a few things to worry about:
-it is heavy at 15 to 18 pounds per square foot- can your roof take it?
-how many drains or scuppers do you have? If the soil gets through the filter cloth and the drains get clogged, that can quickly increase the weight on the roof and cause structural failure.
This old house says "everyone loves an option that cuts out extra labor, materials, and middlemen" but sometimes it is nice to hire someone with experience and lots of liability insurance. ::This Old House and ::Green Grid Roofs