Kailan (Brassica oleracea var. alboglabra) is a leafy vegetable with high economic value whose productivity is strongly influenced by nutrient availability and growing media conditions. Eco-enzyme fertilizer has emerged as a promising environmentally friendly organic fertilizer that may enhance plant growth through the improvement of nutrient availability and biological activity in the growing medium. This study aimed to evaluate the effectiveness of different eco-enzyme fertilizer concentrations in improving the growth of kailan. The research was conducted at the experimental field in Titigalar Hamlet, Baturiti District, Tabanan Regency, Bali, Indonesia. The experiment was arranged in a randomized complete block design (RCBD) with one factor consisting of four eco-enzyme fertilizer concentrations: 0, 50, 100, and 150 mL L⁻¹ of water. Each treatment was replicated three times, resulting in 12 experimental units. The observed variables included plant height, number of leaves, leaf area, and leaf chlorophyll content. Data were analyzed using analysis of variance (ANOVA), followed by Tukey’s Honestly Significant Difference (HSD) test at the 5% significance level. The results showed that eco-enzyme fertilizer application had a highly significant effect on all observed growth parameters, including plant height, number of leaves, leaf area, and leaf chlorophyll content. Increasing eco-enzyme concentrations enhanced vegetative growth compared with the untreated control. The application of eco-enzyme at 100 mL L⁻¹ produced the most favorable vegetative growth, as indicated by superior plant height, leaf number, leaf area, and chlorophyll content. These findings demonstrate that eco-enzyme fertilizer is effective in promoting kailan growth and has considerable potential as an environmentally friendly organic fertilizer to support sustainable kailan cultivation.