In most cases, rooftop agriculture uses soilless cultivation (or hydroponics) of plants, as the yield and the quality of the soilless-grown crops are often higher than those grown in the agricultural soil. In soilless culture, the elements that are essential or beneficial for plant growth and development are supplied through: (i) the addition of organic and/or synthetic fertilisers to the substrate before and after crop plantation; (ii) the supply of a nutrient solution, which is prepared dissolving one or more soluble fertilisers in the raw water and thus is delivered with the irrigation system (fertigation). In this chapter, the basic aspects of the mineral nutrition of hydroponically-grown plants and the methods that could be used for a sustainable management of fertigation in rooftop soilless culture and to improve the organoleptic and nutritional quality of rooftop food crops are described.