It's great to have one, it gives such a feeling of space," says Kiran Kapoor, talking about her terrace garden in Delhi's Greater Kailash II. A gardening enthusiast, Kapoor is among the many metropolis-dwellers who long to tend a green patch in their house where a cup of tea can be served in the morning sun, or a small barbecue under the night sky for friends.

The lack of ground space for a garden hasn't been a deterrent for garden lovers - in fact, ground level space isn't even the preferred choice nowadays, because a green patch at ground level has its share of disadvantages: the constant sound of traffic, the swirl of dust, and only occasional sunlight (as it is blocked out by the surrounding tall structures).

As single dwelling units turn into multiple-level dwellings even in areas not meant for apartments, the top floors in these and the penthouses in multi-storied units are the most prized.

To have a green patch on top that becomes an extension of the activity area of an apartment is what people look for - the open sky, no noise pollution, plenty of sunlight, lots of wind and a gazebo to sit under to enjoy the rains. Terrace gardens or terrace scaping are increasingly speckling urban skylines with green patches and great-looking rooftops.

But the urban skyline isn't the prettiest as rooftops sport water tanks, pipes, abandoned junk or perhaps laundry. "One needs to screen out the surroundings so that the sky becomes the focus, not the neighbour's water tank," says Nandita Parikh, a landscapist with Landscape Designs, recommending the use of jaalis, screens and planters.

But before that, a green patch is not possible until the roof that will support it is structured well and has been waterproofed without cutting corners. Till 6-7 years ago, the lack of good waterproofing made several gardners wary of attempting terrace gardens.

But nowadays builders themselves put in the basics of waterproofing, drainage and irrigation system, even filling in the earth. And Parikh will tell you that "having a terrace garden with a lawn is still a big thing".

Having a pergola, sit-out or a gazebo in stainless steel, glass and wood has become a must for sky gardens. Imported furniture that is weatherproof with a cane or wood look is also popular, apart from the usual wrought iron.

Vidur Bharadwaj, architect, Design and Development, suggests utilising as much waste material in an innovative way to do up the flooring, pavements and seating arrangements for the terrace gardens. The look for a terrace garden is along contemporary, sleek lines, similar to the trend for homes.

"The ethnic look is out," says Parikh, who also suggests dry gardens like the ones in Japan focussing on sculpted plants, figurines and pavements. Water features like cascading water walls that cost a couple of lakh rupees for 1'x 20', or bubblers for Rs 20,000-30,000 too are preferred.

Diffused or mood lighting is usually advised for terrace gardens as often a terrace garden is an extension of a living space. "Highly personal terrace gardens see water bodies, chimes and birdbaths, and gardens meant for gatherings have makeshift bars and pavilions," observes Minesh Parikh, a landscapist with Landscape Designs.

For plants, he suggests using them as sculptures apart from using a lot of evergreen foliage, palms and seasonal favourites. For a 200-300 square yard terrace garden Minesh estimates a cost of Rs 10 lakh (Rs 1 million) at the top end.

If terrace gardens are meant for smaller spaces, for larger terraces in huge projects Bharadwaj sees terrace-scaping or landscaping the terrace as the latest trend to make the usually ugly skyline look better.