This study conducted to investigate the role of the horticultural activities to create and manage the outdoor space of the school, are as follows: Most of the students have had experiences of horticultural activities cultivating vegetables, fruits, flowers, trees, etc., and took part in activities such as planting plants, growing plants, and harvesting plants. These activities were done through the house veranda, garden, or school classes. We found that much of the horticultural activities are done at school, home, and communities, as the students have quite a few experiences in external experiential events or allotment farms. Students had more than average amount of interest in horticultural activities. In particular, the more gardening activity the student experienced, the higher interest they had. About half of the students observe the plants at least once a month and know the names of 3.42 plants among the plants at school. The students in the school that had done the school forest project are aware of relatively many plants and show high observation frequency. Although the schools done horticultural activities in accordance with the curriculum, they usually consist of one-off activities such as planting and seeding in schools without gardens as the activities are done with pots inside the classrooms. The satisfaction with the external school environment was relatively high at schools that done the school forest project, and this was affected by flowers, trees, and resting area. In other words, students must have plenty of flowers and trees to be satisfied with the external school environment and should also have an appropriate outdoor resting area. It is important to provide opportunities to allow students to continue experiencing gardening activities at school and home, because they have a high abundance of experience and interest in horticultural activities. Therefore, the space for horticultural activities considering the school curriculum and preferences of students should be secured and a variety of flowers and trees should be planted in order to create the external environment of school.