Objective: The purpose of this study was to investigate the effects of STEAM-based gardening activities on children’s creativity and nature-friendly attitudes, and to provide basic data on such activities that can be used by early childhood education institutions. Methods: For this study, the program effect during 12 sessions was verified for 32 5-year-olds, with 15 in the experimental group (five males, ten females) and 17 in the comparative groups (eight males, nine females). For the collected data, covariance analysis (ANCOVA) was performed using SPSS 22.0. Results: First, an examination of the effect of STEAM-based gardening activities on children s creativity, showed that they had a positive effect on the total score of creativity. Additionally, it was found that fluency, originality, abstractness, elaboration of the title, and resistance to hasty termination, which are sub-factors of creativity, had a significant effect on the abstractness of the title and resistance to hasty termination. Second, as a result of examining the effects of STEAM-based gardening activities on nature-friendly attitudes, it was found that the total score of nature-friendly attitudes and sub-factors, nature-friendly attitudes, and attitudes toward environmental conservation, were significantly affected. Conclusions: Based on these results, the feasibility of STEAM-based gardening activities was confirmed, and implications for future field applications were derived. It can be seen that it is a meaningful educational tool to cultivate convergence talent.