Abstract: The effect of conventional fertilization was compared with a vermicompost that was mixed with substrate for sweet basil (Ocimum basilicum L.) in a greenhouse experiment. The study was conducted in a completely randomized block design with 4 replications. Eight treatments were compared: a control treatment of a substrate mixture (T0: with no vermicompost added), five treatments with increasing percentages of vermicompost added to the substrate mixture (H1 to H5), and two treatments using two application rates of a chemical fertilizer (F1 and F2). Both fertilizer and vermicompost presented very low levels of heavy metals, which assured agronomical suitability. Vermicompost from SS-MSW (Source-Separated Municipal Solid Waste) and slaughterhouse sludge, presented significant value as soil conditioner and biofertilizer and produced increased levels of C and N (P<0.05). The phosphorus addition by vermicompost was high, with a decrease of zinc absorption by plants and potential contamination risk. Mixtures including more than 50% of the vermicompost and the highest rate of fertilizer showed statistically significant differences for dry weight, leaf length, plant survival and P-Zn antagonism (P<0.05).