If there is one thing the community yearns for, it is more green open space in our urban jungle. People crave to get closer to nature, and most children want to get down and dirty in the great outdoors when given the chance. However, visiting country parks is not always possible during weekdays. An undoubted success in greening the city has been the community gardening programme, launched four years ago by the Leisure and Cultural Services Department. About 20,000 people have now taken part from just 400 in the beginning. It has branched out with 18 gardens - one for each district. The plots under the programme take up a total of 19,000-plus square metres on vacant government land. Members are allotted a small plot, taught the rudiments of gardening and encouraged to grow whatever plants and vegetables they want or are feasible. Unlike those one-off tree-planting days, members have their plots for four months. The gardens are in the heart of each district, so families can easily visit them. Gardening offers an invaluable opportunity to pull children away from television and computer games, teach them about plants and vegetables, and allow them to watch them grow. It draws families closer together, and it is a great way to relieve stress for city dwellers. Given its popularity, it is now time for the department to expand the programme and consider new ideas. Where possible, it should allot more land and introduce more people to community gardening. It should also encourage building owners and property developers to take part by offering classes so residents could tend to their own private plots. This would help further beautify their neighbourhoods. But there is no reason to confine gardening to ground level. In cities across North America and Europe, there is a movement towards greening the rooftops of private and public buildings. The concrete surfaces of buildings absorb and give off heat. This significantly increases the cooling bills and contributes to rising urban air temperatures. Growing vegetation and cultivating gardens on roofs has a remarkable cooling effect. These ideas are worth exploring for an already excellent programme in Hong Kong.