Sam Lawrence, who designed the verdant, eleventh-floor oasis for Jersey City glass tower 77 Hudson, explains how to create your own urban garden in the sky. First, find out how much weight the area can support, says Sam, a principal at HM White Site Architects. You should also consider the amount of wind and sun the garden will receive, what views you want to highlight and if you’d like to use a diverse range of plants to differentiante the layout.