This study was conducted on a sample of 360 students of biotechnical education aged 15 to 18 with the aim of testing the effectiveness of experiential instruction in a school garden in comparison with traditional instruction in a classroom. The results show that experiential instruction yielded significantly better achievement scores than traditional teaching. The experiential instruction group scored higher in both cognitive domains included in the test, i.e. knowing and applying. Students’ knowledge in a post-test was influenced by gender, grade and the educational program that students were enrolled in.