Sweet potato plants grown using an aero-hydroponic system

Rooftop greening not only adds to the scenery, but also delivers a range of environmental benefits, including purifying air through absorbing CO2 and releasing oxygen. Vegetation can also help to mitigate temperature increase and heat island effects through plant transpiration, and reduce air conditioning power consumption through its insulating effect, keeping temperatures down over the whole building.

Aware of these benefits, the NTT Group is actively greening the rooftops of group company office buildings, data centers, telecommunications buildings and other facilities with a diversity of plants including sweet potato, bitter gourd, cucumber, morning glory, loofah, bell pepper, pansy, rape, azalea, Japanese zelkova and lawn grass.

For example, at its Urbannet Mita Building in Tokyo's Minato Ward, NTT Urban Development is growing sweet potatoes using an aero-hydroponic system ^*1, and bitter gourds, grapes and other plants as wall greenery using special bags of soil mixed with fertilizer. It also started beekeeping in fiscal 2011 to test the effectiveness of natural pollination by honeybees.

NTT West Kansai Regional Headquarters has also planted colorful flower beds at its five Kyoto buildings to match the surrounding scenery, and grows bitter gourds that it harvests to serve at social events etc.