October 23, 2006	Monday	Ramazan 29, 1427

ROOF gardens began in Europe a long time back and have now become a latest trend in gardening. Not only are terrace gardens beautiful and unique, they are also efficient in many ways. The trend is becoming popular in Pakistan too, and has caught the attention of many households. Roof gardens also have many advantages.

One advantage of the roof garden is its secrecy. No more kids, vermin, and strangers tromping through your flowerbeds as these are concealed privacy to the outdoor habitat.

It can add economic value to the property due to its aesthetic appeal which catches the attention of people passing through the place.

Terrace gardens absorb a lot of energy by being on top of a structure. They provide natural noise and thermal heat insulation, thereby cutting down on utility bills.

Since the foliage itself needs water and sun, they actually retain twice as much rainfall and sun which results in less water runoff, and flooding. In bigger cities this decreases the excess heat caused by urban heat islands. Terrace gardens actually cool places off to a certain degree.

Space creation: Making gardens on roof tops leave the backyard space for other projects. In a mega city, terrace gardens are the only choice to grow plants away from noise and air pollution.

Not only do these gardens add peace and tranquillity but also improve the natural environment by providing wildlife habitats space for feeding and breeding. These gardens can also provide a beautiful ecological setting for native plants, herbal gardening, rolling exotic grasses, and much more.

Due to extra foliage these gardens re-oxygenate air and retain harmful toxins, allowing people in the house and neighbourhood to reap natural benefits. There is less particulate load in the air (and less asthma) because of terrace gardens which turn dust into soil. City gets quieter as such gardens absorb noise and carbon dioxide from the air.

For developing a terrace garden, the following things should be taken into considerations:

* The selected roof should be strong enough to carry the weight of a garden.

* Water should not accumulate anywhere on a terrace. It should be sloppy with an effective drainage system.

* The most important aspect is water proofing of the terrace. It has to be exceptionally good to prevent the leakage of water for a very long time.

This is started like any other garden. It should have proper balance of lawn, shrubs, ground covers and small trees, if possible. If possible a water-body, rock garden, gazebo and some artefacts can be incorporated into the garden.

First a layer of bricks bat (totally burnt bricks) of approximately 2”x4” is spread evenly on the terrace. The brick bats are used to facilitate the drainage of water. Only the totally burnt bricks should be used because pieces of normal bricks get reduced to mud after some years and defy the very purpose of facilitating the drainage.

The growing medium should be such that it does not add undue weight to the building. Soil rite or peat moss should be light and excellent medium for terrace garden. Certain kinds of manure and growing media are available that can be mixed with silt and used as a subsequent of peat moss which is a bit expansive. The mixture of silt, manure and peat moss is spread to the desired level.

Lastly water bodies, rockeries or sculptures are installed. Plants which do not have a tap root system are then selected. Fibre-rooted plants should be preferred as those with tap root system have the potential of growing through the terrace and endangering the life of the building.

Suitable plants for terrace garden are Nanthra and Iresine as ground cover or border plant, it also adds colour to the landscape. For rockery or to fill a corner, spider plant, black grass, or some medium-sized ornamental grasses can be used.

Annual flowers are an integral part of any landscape, some place should be left to enjoy the seasonal beauty or hanging boxes can be used for this purpose if space permits. In large plants, ficus are excellent for topiary work but it should be in container, and care should be taken that roots are contained, and may not run out of the container and damage the roof or other plants.