In the context of climate change, increasing water scarcity, and the growing accumulation of organic waste, the valorization of food waste into water-retaining soil amendments emerges as a promising innovation for sustainable agriculture. This chapter presents the results of an in-depth literature review and experimental studies on the transformation of food waste into materials capable of enhancing soil water retention capacity. Food waste extracts, processed through biotechnological methods (composting, fermentation, enzymatic treatment), have shown beneficial properties in terms of porosity, biodegradability, and nutrient contribution. These characteristics promote moisture retention in the root zone and improve crop productivity. The integration of such bio-based materials into agricultural practices also presents notable economic benefits, including reduced irrigation costs, the valorization of by-products, and the creation of new market opportunities. This chapter will address: • The physicochemical mechanisms of interaction between valorized waste and soil, • The observed water retention efficiency criteria, • The impacts on soil health and crop yield, • The scalability potential and the technical and economic barriers to be overcome.