This work aimed to evaluate the influence of the substrate composition on the emergence, vigor, and growth of Tabernaemontana catharinensis seedlings in a greenhouse. Seeds were placed to germinate by testing the following substrates: pure Mecplant and combined with fine texture vermiculite (V) or charcoal rice husk (CRH) in different proportions. Variables of emergence percentage, emergence speed index, height, collection diameter, root length, leaf area, dry mass (shoot, root, and total), Dickson quality index, and photosynthetic pigment contents were evaluated. Germinated plants on pure Mecplant substrate presented lower emergence values and morphophysiological parameters. This commercial substrate associated with vermiculite at 1:1 and 1:3 proportions provided higher seed vigor and higher seedling growth, proving to be more adequate for the seedling formation of the species. The formulated substrates did not show a significant influence on the photosynthetic pigment contents.