Gardening for Health Utilizing Traditions (GHUTS) is a new diabetes prevention intervention for urban American Indian and Alaska Native (AI/AN) adults receiving mental health treatment in Los Angeles County. The two main objectives of this study are to: 1) further our understanding of diabetes prevention and the role of gardening for urban AI/AN adults receiving mental health treatment and 2) finalize the development of GHUTS. To inform the feasibility of the intervention and to gain perspective, three focus groups were conducted among urban AI/AN adults receiving mental health treatment (n = 7), providers who serve urban AI/AN people (n = 7), and the GHUTS Community Advisory Board (n = 5). Three overarching conceptual themes emerged: 1) Diabetes is an important issue among urban AI/AN people receiving mental health treatment, 2) AI/AN traditional practices have an important role in diabetes prevention among urban AI/AN adults receiving mental health treatment, and 3) Gardening is beneficial for AI/AN people. Feedback on the GHUTS curriculum featured diabetes education, cultural elements, concerns specific to AI/AN people in Los Angeles County, cooking, physical exercise and diet, prayer and mindfulness, community sharing, and field trips. This study highlights the process of developing a community-grounded diabetes prevention intervention for urban AI/AN adults receiving mental health treatment.