The Pathways and Efficacy of Horticultural Therapy in Promoting College Students' Mental Health: An Explanatory Sequential Mixed-methods Study.

College students receiving horticultural therapy showed significantly higher post-intervention scores in meaning in life, overall affect index, and life satisfaction compared to the control group.

• 112 college students were randomly assigned to an experimental group or control group
• Meaning in life post-intervention difference: p = 0.017
• Overall affect index post-intervention difference: p = 0.044
• Life satisfaction post-intervention difference: p = 0.046

Within the experimental group, post-intervention levels of meaning in life, affect balance, and positive affect were significantly higher than pre-intervention values.

• Meaning in life pre-to-post improvement: p = 0.02
• Affect balance pre-to-post improvement: p = 0.007
• Positive affect pre-to-post improvement: p = 0.019
• The experimental group participated in eight weekly HT sessions of 90 minutes each

Facial expression analysis revealed notable differences in the distribution of seven expressions between the experimental and control groups, with positive expressions increasing over time.

• Seven distinct facial expressions were analyzed using facial expression video analysis
• Positive expressions increased over time particularly during flower arranging and tea tasting activities
• Facial expression video analysis was used alongside standardized psychological scales to assess intervention effects

Qualitative grounded theory analysis identified a four-layer pathway model explaining how horticultural therapy improves mental health.

• The four-layer model follows the pathway: Environment → Cognition → Emotion → Behavior
• Environment layer explained 36% of the variance
• Cognition layer explained 32% of the variance
• Emotion layer explained 16% of the variance
• Behavior layer explained 15% of the variance
• Qualitative analysis used grounded theory with NVivo 12 software on textual data reflecting participants' authentic experiences

The study employed an explanatory sequential mixed-methods design combining quantitative intervention assessment with qualitative grounded theory analysis.

• Quantitative phase used standardized psychological scales and facial expression video analysis
• Qualitative phase collected textual data and analyzed it using grounded theory with NVivo 12
• HT activities included flower arrangement and herbal tea tasting
• Intervention consisted of eight weekly sessions of 90 minutes each