The most widespread, internationally, organic substrate material for growing ornamental plants is peat. Peat however is imported in most countries and it is an expensive material. In addition, it is considered a non-renewable natural resource and its intensive extraction has negative environmental impacts. Therefore, even the partial replacement of peat in the substrate of ornamentals by other cheap and organic materials available in large quantities is required. In this study, the effect of green-waste compost (GWC) combined or not with fertilization on growth of Ficus benjamina was studied, in order to evaluate the possibility of replacing part of the peat of the substrate with this compost. Rooted cuttings were cultured for 10 months on peat-perlite (1:1 v/v, control substrate) and on three other substrates, where 25, 50 or 75% of peat (by volume) was replaced by GMC. Half of the plants in each substrate were fertilized weekly with a complete water soluble fertilizer (20:20:20). Plant growth was evaluated at the end of the experiment recording plant height, thickness of the main stem, number and length of lateral shoots, as well as dry weight of the above-ground and the root biomass. GMC promoted growth of the non-fertilized plants, but it could not replace fertilization, since only in two of the growth assessment parameters, that of the main stem thickness and the dry weight of the roots, the replacement of peat by GMC at 50 or 75% without fertilization induced similar values with the fertilized control. When fertilization was applied, the GWC successfully replaced peat at even 75% yielding quite satisfactory plant growth similar to that of the control.