Five media prepared from old peat (OP), white peat (WP) and municipal solid waste compost (MSWC) were used to determine optimum growing media for tomatoes (Lycopersicum esculentum Mill. cv "Atletico"). The mixtures of substrates used were: OP (65%) + WP (30%) + perlite (5%), OP (65%) + MSWC (30%) + perlite (5%), WP (65%) + OP (30%) + perlite (5%), WP (65%) + MSWC (30%) + perlite (5%), MSWC (65%) + WP (30%) + perlite (5%). Various seedling indices were measured in order to assess the quality of the nursery-produced plant. Nursery-produced tomato seedlings grown in WP (65%) + MSWC (30%) displayed quality indices similar to those recorded for conventional mixtures of old and white peat sphagnum, due to a correct balance between the compost nutrient supply and the porosity and aeration provided by white peat. (c) 2007 Elsevier Ltd. All rights reserved.