In this study, the effects of vermicompost on the morphological characteristics of 1+0 aged oriental beech (Fagus orientalis Lipsky.) in different planting densities were investigated. Seedlings were grown under eight different conditions, including four different planting densities with and without vermicompost. Robustness, volume, and quality indices were calculated using the morphological quality criteria, e.g., height, root collar diameter, and dry weight at the end of the growing season in 1+0 aged seedlings. An analysis of variance (ANOVA) was used to determine the effects of vermicompost application and planting density on the morphological characteristics of oriental beech. The Duncan test was used to categorize significant differences from the ANOVA, and a correlation analysis was used to determine the direction and significance of the relationships among the parameters. An increase in planting density negatively affected seedling development in both the treatment and control groups. The best development in the control group was found in seedlings planted at a 10-cm planting density, which had a height of 16.0 cm, root collar diameter of 4.98 mm, and a seedling dry weight of 1.683 g. At the same time, the group planted at the same density with vermicompost had a height of 18.5 cm, root collar diameter of 6.07 mm, and seedling dry weight of 2.030 g. Seedlings grown at the highest planting density and treated with vermicompost had better development performance than all groups without vermicompost, even at the lowest density. In addition, the decrease in seedling development associated with an increased planting density was lower than that observed in the vermicompost group. The results of this study indicate that the vermicompost treatment positively contributed to the seedling development of oriental beech and the propagation of morphologically high quality seedlings, even at high planting densities.