Aiming tThis study aims at evaluating the physical, chemical and biological characteristics of sewagesludge and its feasibility for use as a component of substrata to produce seedlings of native and exotictrees. The sewage sludge was previously stabilized through the process of composting with grassremnants. Before and after the composting, chemical analyses were carried out in order to quantifylevels of heavy metals, macro nutrients and micro nutrients in addition to microbiological analyses ofsewage sludge. The mixtures (Treatments) in the proportions vary from 0 to 100% of organic compostof sewage sludge (OCSS) in composition with carbonized rice husks (CRH) and were compared tocontrol treatments, which consisted of commercial substrates (PLANTMAX-EUCATEX) and cattle manure.Porosity, density, capacity of water retention and particles size of treatments were evaluated. Resultsof the physical characterization of substrates revealed that proportions ranging from 100 to 40% of thecompost showed better results for tree seedlings cultivation. The use of organic compost of sewagesludge (OCSS) to produce seedlings of forest essences is a viable alternative for waste reuse,aggregating not only economy and quality of inputs in the yields, but also environmental benefits.