A roof garden is a garden on the roof of a building. Besides the decorative benefit, roof plantings may provide food, temperature control, hydrological benefits, architectural enhancement, habitats or corridors for wildlife, recreational opportunities, and in large scale it may even have ecological benefits. The practice of cultivating food on the rooftop of buildings is sometimes referred to as rooftop farming. Rooftop farming is usually done using green roof, hydroponics, aeroponics or air-dynaponics systems or container gardens.
In New York City between 1880 and Prohibition large rooftop gardens built included the Hotel Astor (New York City), the American Theater on Eighth Avenue, the garden atop Stanford White's 1890 Madison Square Garden, and the Paradise Roof Garden opened by Oscar Hammerstein I in 1900.
Available gardening areas in cities are often seriously lacking, which is likely the key impetus for many roof gardens. The garden may be on the roof of an autonomous building which takes care of its own water and waste. Hydroponics and other alternative methods can expand the possibilities of roof top gardening by reducing, for example, the need for soil or its tremendous weight. Plantings in containers are used extensively in roof top gardens. Planting in containers prevents added stress to the roof's waterproofing. One high-profile example of a building with a roof garden is Chicago City Hall.
For those who live in small apartments with little space, square foot gardening, or (when even less space is available) green walls (vertical gardening) can be a solution. These use much less space than traditional gardening. These also encourage environmentally responsible practices, eliminating tilling, reducing or eliminating pesticides, and weeding, and encouraging the recycling of wastes through composting.
Singapore is active in green urban development. "Roof gardens present possibilities for carrying the notions of nature and open space further in tall building development." When surveyed, 80% of Singapore residents voted for more roof gardens to be implemented in the city's plans. Recreational reasons, such as leisure and relaxation, beautifying the environment, and greenery and nature, received the most votes. Planting roof gardens on the tops of buildings is a way to make cities more efficient.
A roof garden can be distinguished from a green roof, although the two terms are often used interchangeably. The term roof garden is well suited to roof spaces that incorporate recreation, and entertaining and provide additional outdoor living space for the building's residents. It may include planters, plants, dining and lounging furniture, outdoor structures such as pergolas and sheds, and automated irrigation and lighting systems.
Although they may provide aesthetic and recreational benefits a green roof is not necessarily designed for this purpose. A green roof may not provide any recreational space and be constructed with an emphasis on improving the insulation or improving the overall energy efficiency and reducing the cooling and heating costs within a building.
Green roofs may be extensive or intensive. The terms are used to describe the type of planting required. The panels that comprise a green roof are generally no more than a few centimeters up to 30 cm (a few inches up to a foot) in depth, since weight is an important factor when covering an entire roof surface. The plants that go into a green roof are usually sedum or other shallow-rooted plants that will tolerate the hot, dry, windy conditions that prevail in most rooftop gardens. With a green roof, "the plants' layer can shield off as much as 87% of solar radiation while a bare roof receives 100% direct exposure".
The planters on a roof garden may be designed for a variety of functions and vary greatly in depth to satisfy aesthetic and recreational purposes. These planters can hold a range of ornamental plants: anything from trees, shrubs, vines, or an assortment of flowers. As aesthetics and recreation are the priority they may not provide the environmental and energy benefits of a green roof. 2b1af7f3a8