Gardens in the Sky
Rooftop gardens were once a rarity in large cities, but a growing number of office buildings now grow vegetables above their top floor. The plants shade the roof, which keeps the floors below noticeably cooler in summer, and staff have somewhere quiet to take a break. Wet soil is extremely heavy, however, so older roofs usually have to be strengthened before any planting can begin, and that can make a garden far more expensive than planned. Even so, several city councils now offer grants towards the cost.