On June 1, 2024, the American Horticultural Therapy Association (AHTA) began accepting applications for a new professional credential-therapeutic horticulture practitioner, THP. Since the establishment of THP there has been some confusion and misunderstanding surrounding the innovation of a new professional designation. This month’s blog will endeavor to explain, in detail, what the THP credential involves, how it differs from the HTR credential and what to expect if you are considering THP. At the end of this article, you will find an informational chart that will hopefully serve as a resource.
Defining Therapeutic Horticulture Practitioner
The THP credential is intended for practitioners who provide therapeutic horticulture services aligned with the AHTA definition:
- The engagement of a participant in active or passive horticultural-related activities.
- The participant has an identified disability, illness, or life circumstance requiring services.
- The activity is facilitated by a registered horticultural therapist or other professional with training in horticulture.
- Participation is in the context of the goals and mission of the organization.
The designation Therapeutic Horticulture Practitioner (THP) ensures that professional competencies have been achieved based on standardized academic requirements and professional training.
Who is eligible to apply for THP?
To apply for the credential, you must meet the AHTA’s requirements. You must be a current member of AHTA at Associate Level 1 or Associate Level 2-year 3. You must also have completed all 9 semester credits of HT course work from one of the accredited AHTA certificate programs. And you must have a minimum of 500 hours of work experience in therapeutic horticulture and related services. The hours may be paid or unpaid and include employment and/or volunteer services.
The 500 hours of work experience requirement has been one area of confusion. The AHTA defines work experience as “documented delivery of therapeutic horticulture service”. This is divided into two parts, direct client services and non-direct client services. Direct client service is direct client contact, utilizing horticultural activities as the primary modality. Non-Direct Client Services are the program support tasks which include documentation, session planning/preparation, client meetings and supporting horticulture (gardening) tasks.
The 500 hours also must meet a 60/40 rule. Sixty percent (300 hours) must be direct client service. Up to 40% (200 hours) can be non-direct client service. A detailed description of the 500 hours of work experience can be found in section II-B of the AHTA Professional Registration Policies and Procedures-THP.
A distinction between work experience for THP and the 480-hour HTR internship, is that no supervision by an HTR is required for the work experience hours. Other than that, the direct and non-direct client service requirements are largely the same for both credentials.
THP as a stage of progress toward HTR
The AHTA does provide a pathway for THP professionals to gain their HTR credential if desired. The process and requirements are described in the AHTA Professional Registration Policies and Procedures-THP, section I-C titled Eligibility to Reclassification for Horticultural Therapy Registered. To explain this briefly, if the THP wishes to acquire the HTR credential, reclassification offers some choice regarding the internship/work experience hours only. All academic requirements remain the same as the traditional path to registration.
“I was already working in TH, doing what I loved. Not everyone has the resources, interest, or access to become a registered horticultural therapist (HTR), the THP credential opens doors for talented practitioners to earn professional standing.” ~Megan Goulden, THP
The THP has an option to continue to work an additional 1,000 hours for a total of 1,500 hours in place of the internship requirement. At this point there appears to be no specific time frame for completing the additional hours. For the HTR internship a stipulation is in place that states, “Once an internship begins it must be completed within a minimum of three months and a maximum of two years totaling 480 hours”. It seems likely that the AHTA will soon establish a similar time frame for the additional work hour requirement.
Who might consider the THP credential?
Megan Goulden, THP, was working through an HTR internship when she learned about the THP credential. “I was excited when I heard about the opportunity to apply for AHTA’s new Therapeutic Horticulture Practitioner (THP) designation. It felt like it was the natural next step. The application process was straightforward, taking about four months.”
Goulden grew up playing outside in old fruit orchards, picking flowers and gardening with her father. After losing both her parents in her 30’s she was urged to create a memory garden. The process of creating and tending to a garden space provided purposeful activity that enabled Megan to work through her grief. It was a few years later that she learned about horticultural therapy and the science behind it. For the first time she understood the relationship between her sense of connection in the garden and her emotional well-being. She began classes at HTI and earned her certificate in 2017.
Megan has worked in the HT field since 2018 serving many different populations, adults with developmental disabilities, seniors aging in place, those with mental health challenges, and school-aged children. Despite more than 14 years working as a master gardener, having an HT certificate and completing hundreds of internship hours, she began to wonder when or if she would ever complete the HTR requirements. Choosing to apply for the THP credential seemed like the best option.
“While having my THP has not changed how I work, it has deepened my sense of responsibility to contribute to our growing field and strengthened my connection to the HT community. AHTA’s willingness to try new things, such as the THP credential, will strengthen the HT/TH presence in our communities. I am proud to be part of this passionate, creative, and caring profession.” It is likely that the THP credential process will continue to evolve in the coming years. As of this writing, February 2025, the following information chart details current requirements for both the HTR and THP credentials.
Horticultural Therapy Professional Registration for THP & HTR
| Certificate in Horticultural Therapy | Therapeutic Horticulture Practitioner | Registered Horticultural Therapist | |
| Credential | NO | YES-THP | YES-HTR |
| Completed Accredited Certificate Program | YES | YES | YES |
| Earn 9 College Credits in HT coursework | NO | YES | YES |
| AHTA Membership | Associate Level One or Associate Level Two | Associate Level One or Associate Level Two | |
| Complete a baccalaureate degree | NO | YES | |
| Work Experience | Complete a minimum of 500 hours in therapeutic horticulture and related services. Can be employment or volunteer hours | 480-hour Internship is required | |
| Additional Coursework in Human Science & Plant Science | NO | As needed to meet requirement: 12 College Credits-Human Science 12 College Credits-Plant Science | |
| Internship | *Internship must be supervised by an HTR. Several supervision options are available. | ||
| Apply to AHTA for credential | Not an option | YES | YES |
| Notes | CHT or HT-C are not credentials and should not be used. | *Complete information on work experience hours can be found on the AHTA website THP page. | *Complete information on internships can be found on the AHTA website Internship page |
