© 2020, Sociedad Chilena de la Ciencia del Suelo.Cordyline is one of the most important indoor pot plants and has a high request in the global market. As a bio-stimulant, chitosan could be used to enhance the plant growth and productivity, despite the variation in growth analysis and phenotypic plasticity of several plant species in response to chitosan supplement. Cordyline seedlings were foliar sprayed with five concentrations of oligo-chitosan (0, 25, 50, 75, and 100 mg L−1) for 4 months. Oligo-chitosan induced rapid growth of cordyline seedlings, in terms of larger specific leaf weight (SLW) and higher relative growth rate (RGRA), as well as improving the efficiency of plant photosynthesis (high net assimilation rate (NAR) or low specific leaf area (SLA)). Root growth rate (RGRR) has also increased by 89.13% with the application of 50 mg L−1 oligo-chitosan, which reflected on higher plant biomass (BM) in comparison to the control. Consequently, root biomass (RM) showed the greatest plasticity index (PPI) that enhanced growth, productivity, and quality as well as the marketability of cordyline seedlings. Foliar spray of 50 mg L−1 oligo-chitosan improved plant growth, root development, and plasticity index, resulted in increased quality and marketability of cordyline seedlings.