Therapeutic Horticulture Practitioner (THP)

The American Horticultural Therapy Association is pleased to announce a new professional credential – The Therapeutic Horticulture Practitioner, THP.

The THP 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.
  • The participation is in the context of the goals and mission of the organization.

Application Process 

Please complete the online application, which allows you to upload supporting documentation, and pay the $100 application fee. All application materials must be submitted online.  

                                                 Submit Your Online Application                                     

Applications are evaluated by AHTA's Professional Registration Review Board. An applicant is required to complete the online AHTA professional registration application, provide official transcripts for verification of horticultural therapy coursework, and include a completed, signed Work Verification Form

Review the Policies and Procedures Therapeutic Horticulture Practitioner for full application details. 

Please note: If you are submitting courses from an educational institution that uses a quarter system as opposed to a semester system, a conversion table is available for your use. All AHTA professional registration course requirements are semester credits NOT quarter credits. If you have any questions, please contact the AHTA office. 

There are two ways to pay your application fee: 

  1. You may pay your application fee online at time of application.
  2. Mail a check to the AHTA office address listed below.

    AHTA Office
    2150 N 107th St, Ste 330
    Seattle, WA 98133 

Eligibility for the Therapeutic Horticulture Practitioner 

To be eligible for Therapeutic Horticulture Practitioner, an applicant is required to:

  1. Be a member of AHTA as an Associate Level One (1) or as an Associate Level Two (2)-year 2.
  2. Have completed all nine semester credits of horticultural therapy coursework. 
  3. Have a minimum of 500 hours of work experience in therapeutic horticulture and related services. Hours may be paid or unpaid and may include employment and/or volunteer service.
Professional Registration Policies and Procedures Therapeutic Horticulture Practitioner


Work Experience Hours

Work experience is defined as a combination of therapeutic horticulture service delivery, non-direct client services, and supporting horticulture responsibilities. Therapeutic horticulture service delivery is defined as direct client contact utilizing horticultural activities as the primary modality.

Of the 500 hours, a minimum of 60% must be in therapeutic horticulture service delivery, or 300 hours, and a minimum of 40% of the total hours, or 200 hours, may be client-related responsibilities and/or supporting horticulture services. 

Examples of the hours in each category include: 

  1. Direct client hours providing therapeutic horticulture services to clients in a group or one-to-one.
  2. Non-direct client services like client documentation, program planning and preparation for client activities and/or groups, and client or multi-disciplinary team meetings.
  3. Horticulture responsibilities like gardening, greenhouse and/or landscape maintenance, and pest management.

The online THP application, along with a work verification form completed by both the applicant and the supervisor, and transcripts documenting coursework is all that is required. Full details, information, and forms will be available on the AHTA website soon.

Applicants granted professional registration as a Therapeutic Horticulture Practitioner will be required to renew annually at the Professional level and must maintain their membership in good standing to use the professional designation THP.

Reclassification for the HTR, Registered Horticultural Therapist

An important professional option available to the Therapeutic Horticulture Practitioner is the ability to advance to Horticultural Therapist-Registered, HTR, under a reclassification option. 

The AHTA currently awards the professional designation Horticultural Therapist-Registered, HTR. The HTR requires coursework in plant science, human science, and horticultural therapy, in addition to a horticultural therapy internship or equivalent work experience. 

A THP may apply the 500 hours of work experience in therapeutic horticulture toward the required 1,500 hours internship-work experience option for the HTR. With an additional 1,000 hours of work experience, a THP will have the required hours.

When working toward future professional registration at the HTR level, therapeutic horticulture practitioners should review the AHTA Professional Registration Policy and Procedures for Horticultural Therapist-Registered for information about all the HTR requirements.