Therapeutic Horticulture Practitioner (THP)
What is THP?
The Therapeutic Horticulture Practitioner (THP) registration recognizes professionals with education in horticultural therapy and practical work experience providing therapeutic horticulture services.
THP is Your Starting Point — THP is the entry-level professional registration in horticultural therapy. It’s perfect for those beginning their career or formalizing their experience.
Once you gain additional training and hours, you can upgrade to HTR (Horticultural Therapist-Registered).
THP vs. HTR
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Before Your Start
The application form does not save your progress. Please gather all required documents and set aside 30–45 minutes to complete your application session. Review the checklist below before beginning.
Am I Eligible?
Eligibility Checklist
You must complete ALL requirements to apply.
- Current AHTA Membership: You must be an Associate Level I or Associate Level II member in year 3 or beyond
- Horticultural Therapy Education: Completed coursework specifically in horticultural therapy
- Work Experience: 500 documented hours providing therapeutic horticulture services
Educational Requirements for THP
THP requires nine (9) semester credits of focused coursework in horticultural therapy.
Unlike HTR, you don't need extensive plant and human science education—the focus is on solid foundational knowledge in therapeutic horticulture practice.
How to Complete Your Horticultural Therapy Coursework
There are two ways to complete these course requirements. Either:
- AHTA Accredited Certificate Program — Complete a program recognized by AHTA
- Independent Study Courses — Academic coursework covering required HT content (not hands-on work experience)
Required Content Areas (HT coursework)
Your horticultural therapy coursework must cover these four core topic areas:
1) The Profession
• Definition & history of HT
• Program types (HT vs therapeutic horticulture)
• AHTA overview
• Code of Ethics & Standards of Practice
• Professional registration overview
2) Client Populations
• Psychological: Mental illness, substance use, ADHD
• Physical: Spinal injury, orthopedic, cerebral palsy
• Sensory: Vision, hearing, sensory processing
• Developmental: Intellectual disabilities, autism, Down syndrome
• Disease: Cancer, dementia, stroke
3) Program Tools & Techniques
• Client assessment & documentation
• Goals & objectives development
• Activities & modifications
• Plant material selection
• Adaptive tools & equipment
• Accessible indoor/outdoor spaces
• Therapeutic garden design
4) Program Management
• Short & long-term planning
• Program proposals
• Budgets & funding
• Multidisciplinary team collaboration
• Volunteer management
• Program promotion
• Research & evaluation methods
Important Notes About Topic Areas: These represent content areas, not specific course titles. A single course may cover multiple topic areas, or you may need several courses to cover all content.
Independent Study Requirements: If using independent study, coursework must be academic in nature and reflect the required content. Contact the office for pre approval of your independent study contents.
Work Experience: The 500 Hours
Your 500 hours of documented work experience are a critical component of THP eligibility. Here's what you need to know:
What Counts
• Planning HT programs
• Leading HT sessions with clients
• Adapting activities for participants
• Documenting client progress
• Evaluating program outcomes
• Supervising therapeutic activities
What Doesn't Count
• General gardening maintenance
• Landscape installation
• Teaching traditional horticulture classes
• Volunteer work without therapeutic focus
• Personal garden projects
• Unrelated work experience
Pro Tip: Document as You Go
Keep a detailed log of your hours throughout your work experience. Include dates, settings, populations served, and activities conducted. This makes completing your verification form much easier!
Who Can Sign My Verification Form?
Your supervisor or employer must sign your Verification of Work Experience form.
- This should be someone who can attest to your hours and the nature of your therapeutic horticulture work.
- They don’t need to be an HTR, but they should be familiar with your work.
Required Documents Checklist (HTR)
Gather these materials BEFORE starting your application:
- Official Transcripts — From all institutions where you completed horticultural therapy coursework (must be sent directly from the institution or in sealed envelope)
- Completed Online Application — AHTA professional registration application form
- Verification of Work Experience–THP Form — Must be completed and signed by your supervisor or employer, documenting dates and 500 hours of work
- Proof of Services Rendered — If applicable, additional documentation showing your therapeutic horticulture work
- Application Fee — $100 (online payment or check)
Document Format Requirements:
- All documents must be submitted online.
- Acceptable formats are clean scanned copies in JPEG or PDF format.
- It is your responsibility to verify all materials have been received.
- Applications will not be reviewed until ALL documents are received.
How to Apply: Step-by-Step
01
Verify Your Eligibility
Review the eligibility checklist above. Make sure you meet ALL requirements before proceeding. Confirm your AHTA membership is current and at the appropriate level (Associate Level I or II, year 3+).
02
Gather Your Documents
Collect all required materials BEFORE starting your application. Including:
• Order official transcripts from your institution(s)
• Complete and get your Verification of Work Experience–THP form signed
• Scan all documents in JPEG or PDF format
• Prepare proof of services if applicable
03
Complete the Online Application
Set aside 30–45 minutes in a quiet space. The form does not save, so you must complete it in one session. Have all documents ready to upload.
04
Pay Application Fee
Submit $100 payment
• Online at time of application (recommended)
• Mail check to: AHTA Office, 8635 W Sahara Ave #711, Las Vegas, NV 89117
05
Verify Submission
After submitting, verify that all your materials have been received. It’s your responsibility to ensure everything is complete. Contact AHTA if you have concerns about any documents.
06
Wait for Review
Your application will be evaluated by the AHTA Professional Registration Review Board. Expect results in 6 weeks from the date all materials are received.
Fees & Timeline
Application Fee
$100 (One-time payment)
Review Time
6 weeks (From complete submission)
Annual Renewal
Professional Membership required to maintain THP
Reinstatement Fee
$50 (If membership lapses 3+ months)
IMPORTANT: Maintaining Your Regstration
Once approved, you must maintain Professional-level AHTA membership annually to keep your HTR status. After 3 months of lapsed membership, you'll pay a $50 reinstatement fee. After 2 years of lapsed membership, you must reapply for registration.
THP Registration Resources
THP Frequently Asked Questions
What if my school uses quarters instead of semesters?
No problem! Use our quarter-to-semester conversion table to calculate your credits. All AHTA requirements are listed in semester credits.
Can I upgrade from THP to HTR later?
Absolutely! Many professionals start with THP and upgrade to HTR when they've completed additional requirements. The reclassification fee is $125 and requires 1,000 additional documented hours.
What counts as “work experience”?
Documented hours providing therapeutic horticulture services. Your supervisor must sign the Verification of Work Experience form confirming your dates and hours.
How do I maintain my registration?
Renew your Professional level AHTA membership annually. After 3 months lapsed, a reinstatement fee applies. After 2 years, you'll need to reapply.
What if my application is incomplete?
Your application won't be reviewed until all materials (especially transcripts) are received. You're responsible for verifying everything is submitted.
Ready to Apply?
Make sure you have all required documents ready before starting your application.
Need Help?
Ready to Advance? Upgrade to HTR
Many professionals start with THP and later upgrade to HTR (Horticultural Therapist-Registered) as they gain more experience and complete additional requirements.
THP to HTR: What You'll Need (Requirements / Details)
Additional Hours — 1,000 more hours (bringing your total to 1,500)
Expanded Education — Coursework in plant science and human science
Internship Option — Can complete approved internship instead of additional hours
Reclassification Fee — $125 application fee
Timeline — 6 weeks review process
Benefits of Upgrading to HTR:
• Enhanced professional recognition
• Demonstrates advanced competency
• May lead to increased career opportunities
• Shows commitment to professional development