Abstract Tannery sludge has been highlighted for substrate use in the propagation of seedlings, combining the solution of an environmental problem with its potential for agronomic use. However, when a new fertilizer component enters into the composition of a substrate, it remains to be seen whether other characteristics are affected. Thus, the objective of this work was to verify whether supplementary foliar fertilization is necessary when using a substrate with tannery sludge in the propagation of conilon coffee seedlings of the variety “Vitótria Incaper - 8142”. A 2×13 factorial arrangement was used, the first factor being the presence or absence of conventional leaf fertilization, and the second factor being the 13 coffee conilon Vitoria-Incaper 8142 genotypes arranged in a randomized complete block design with four replications. The genotypes V7 and V9 presented leaves of reduced size, leading to a smaller leaf area, which coincided with a lower accumulation of aerial and total dry matter mass. Higher flavonoid indexes were found in the genotypes V1, V2, V6, and V13, indicating a higher sensitivity of these materials to the components present in the tannery sludge. In general, fertilization provided better initial development as well as a better seedling quality index.