How is expanding plants on a roof considered "green"?

Some recent developing plants Tip on Aquaponic:
Query by furthermore_82: How is developing plants on a roof thought of "green"?
At my local university, they just finished constructing the campus' first "green" building. It has all the common items with solar panels for heating, rainwater collection bin, and so on. However, the creating attributes plants developing on the roof. How is this regarded as "green"? What objective does that serve?


Greatest answer:
Answer by roadhazzardsEffectively

Make Aquaponics System