Ph.D. in Horticulture



The Ph.D. in Horticulture is granted for proven ability in research and scholarship. The student conducts research under the guidance of the major professor with input from the student’s doctoral committee. The doctoral committee consists of a minimum of five members of the graduate faculty, including at least two from the Department of Horticulture and a representative from the Graduate Council.


  • There is no rigid credit requirement; however the equivalent of at least three years of full-time graduate work beyond the bachelor’s degree (at least 108 graduate credits) is required.
  • The equivalent of one full-time academic year in regular non-blanket course work (at least 36 graduate credits).
  • A graduate student who holds an M.S. degree must file a study program with the graduate school by the end of one calendar year of enrollment as a Ph.D. student. This program is formulated and approved at a formal meeting of the student's doctoral committee prior to this date.
  • No more than 15 hours of blanket-numbered courses (e.g., 501, 507, etc.), other than thesis (Hort 503), may be included in the program.
  • The Department of Horticulture requires the following be included in a student’s Ph.D. study program:
    • HORT 507 (1 credit), Horticulture Seminar. The student presents a seminar at the regularly scheduled time of the department seminar (Tuesdays at 4:00 pm).
    • HORT 511 (2 credits), Research and Educational Perspectives in Horticulture, to be taken the first Fall term of enrollment (not required if the student earned these credits as an MS student).
    • A minimum of 6 credits of ENT/HORT 518, PBG/HORT 519, or HORT 520 (two credits per course).  At least one course should be related to the student's area of emphasis, but students are encouraged to enroll in other topic areas.
  • Successful completion of an oral preliminary examination. In Horticulture it is the prerogative of a major professor to require a written comprehensive examination as well.
  • Successful completion of a final oral examination, which includes a defense of the thesis.

Courses in the major, Horticulture, may be selected from those in Horticulture (i.e. with a Hort designation) as well as from those offered by many other departments and programs.


Learning Outcomes: 

Through successful participation and completion of a Doctoral degree in Horticulture students will gain an advanced understanding of horticulture and the interaction with related disciplines, and conduct original research that advances the field of horticulture. Students will be trained through disciplinary coursework and research experience to provide soil science expertise and will have the breadth of knowledge to be able to communicate with professionals from the broad range of specialties involved in horticultural systems management and research.


Graduates will have the ability to conduct original research that extends knowledge in the field of horticulture. This will be demonstrated through mastery and application of critical thinking in the design and conduct of original research, and application of standard and innovative theory and methods in both coursework and an individual thesis research project.

Outcome 2: KNOWLEDGE

Graduates will be able to demonstrate:

• In-depth disciplinary knowledge and capacity to apply that knowledge to horticultural systems issues at multiple scales and levels of biological organization.

• Skill in integrating horticultural systems concepts across multiple disciplines.

• Original and innovative contributions to the understanding of horticultural systems.

• The ability to employ technical knowledge and leadership skills to a horticulture research problem.

Learning outcomes specific to Horticulture students:

• Ability to perform basic analyses in horticulture.

• Ability to perform other basic tasks required of a professional horticultural researcher.

• Understand key linkages and interactions between horticulture and other biological and earth science processes.

• Ability to make original contributions to the understanding of horticultural systems.

These outcomes will be accomplished through successful completion of the coursework required for the degree and a dissertation research project.


Graduates will have the ability to communicate professionally and with the public about horticulture research and horticultural resources. They will gain skills and experience in communicating in both formal and informal venues with learners, practitioners and community members. This will be demonstrated through presentation of a thesis, a special non-thesis seminar and a teaching assignment.


Graduates will have a commitment to diversity and high ethical standards in scholarship, teaching and service. This will occur through participation and training in research methods courses, professional development courses, and seminars, workshops, or other activities focused on diversity and ethics. 


Graduates will demonstrate awareness of the broader implications of their research. These broader implications can include the linkages and relationships between the student’s research and aspects of broader society such social relationships—including issues relating to diversity equity and inclusion, economics, and environmental impacts. This will be demonstrated through exploration of these issues in the thesis, as part of the thesis seminar, or during the final exam.





Learn more: 

Degree: Horticulture

Level: Doctor of Philosophy (Ph.D.)

Department:Department of Horticulture

Class Location: Corvallis Campus

Contact Us: 

For more information or to review our admissions process, please contact:

Elaine Clark
Oregon State University
4017 ALS Building
Corvallis, OR 97331-3002
Phone: (541) 737-5477
Fax: (541) 737-3479

Degree Requirements - OSU Catalog

John Lambrinos
Director of Graduate Programs
4137 Ag Life Sciences Bldg
Corvallis, OR 97331-3002
Phone: (541) 737-3484


Graduate Program

How to Apply

M.S. in Horticulture

Accelerated Master's Platform in Horticulture

Financial Support

Graduate Courses

Graduate Courses AY 2023-2024

Graduate Student Handbook

Graduate Student Success

Graduate Certificate (Online)


Graduate News

Horticulture Graduate Council

Graduate School News