You are currently intervening or wishing to intervene in a dense urban context to respond to issues of food security and improve livelihood conditions? This handbook is for you! Following the evaluation of all of its sack-gardening projects, SOLIDARITÉS INTERNATIONAL (SI) wished to formalise its experience through this technical handbook. NGOs, including SI, are increasingly led to intervene in contexts of high density (whether in camps or in slums): this handbook is thus set within this dynamic. It provides the keys for assessing the relevance of a sack-gardening project, as well as the tools for its implementation. Nonetheless, all methodologies and tools proposed in this handbook shall be further contextualised in case of a replication of this project.