Objectives The purpose of this study was to verify the effects of garden activities on the eating habits, picky eating, and environmentally friendly attitudes of 4-year-old children. Methods Twelve children from A Daycare Center located in Gyeonggi Province were randomly assigned to the experimental group, and 12 children from B Daycare Center were randomly assigned to the comparison group. The experimental treatment was conducted three times a week for 13 weeks from April 15, 2024 to July 12, 2024.The experimental group experienced garden activities and conducted theme activities. Data processing was performed by comparing and analyzing the pre- and post-scores of the experimental and comparison groups using t-tests and using SPSSWIN 25.0. Results First, the experimental group that experienced gardening showed significant differences from the comparison group in both eating habits and sub-variables. Second, the experimental group that experienced gardening showed significant differences from the comparison group in all picky eating. Third, the experimental group that experienced gardening showed significant differences from the comparison group in both environmentally friendly attitudes and sub-variables. Conclusions It is significant that the effects of garden activities on children's eating habits, picky eating, and environmentally friendly attitudes have been verified, and it suggests that it can be applied to actual early childhood education settings to foster children's eating habits, picky eating, and environmentally friendly attitudes.