In Vietnam, urban agriculture still represents a substantial share of food supply and employment. Its contribution to the food needs of the entire population of Hanoi was estimated at 44 per cent in 2002 (Mai et al., 2004). In the same year, over 70 per cent of leafy vegetables originated within a 30 km production radius of the city (Moustier et al., 2004). Cu Chi district, a suburb of Ho Chi Minh City, is the major provider of leafy vegetables to this city (Cadilhon, 2005). About 30 per cent of the population around Hanoi Province and in the periurban districts of Ho Chi Minh City is engaged in agriculture (Hanoi Department of Agriculture and Rural Development, 2009; Dang, 2008).