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Doctor of Philosophy (PhD)

Once obtained, the PhD degree represents the ability of the recipient to conduct original research and scholarly work at the highest level without supervision. As stated in the NCSU Graduate Catalog, “The degree is not granted simply upon completion of a stated amount of course work, but rather upon demonstration by the student of comprehensive knowledge and high attainment in scholarship in a specialized field of study. The student must demonstrate this ability by writing a dissertation reporting the results of an original investigation and by passing a series of comprehensive examinations in the field of specialization and related areas of knowledge.”

To be admitted to the PhD program, you must have a BS and MS degrees from accredited institution(s). Occasionally, the department will admit a qualifying student directly into the PhD program after completing their BS degrees. These students must have obtained three or more years of professional experience in a related area of horticultural science after completion of their BS degree and high GPA/GRE scores.

The following links are vital information to the Doctor of Philosophy program.


Bachelor of Science / Master of Science courses

  • Horticultural Science or Landscape Horticulture courses (in your area of interest)
  • Background courses: advanced math, statistics, general and organic chemistry, and physics
  • Biology courses: plant biology, botany, plant physiology, plant pathology, entomology, soils, genetics/genomics/biotechnology, and biochemistry

Basic requirements

  • GPA of 3.0 or better for the BS and MS degree programs
  • For non- native English speakers, minimum TOEFL scores of 80 or better
  • A GPA of 3.0 must be maintained for all graduate course work during the degree program.
  • All degree requirements must be completed within ten calendar years, beginning with the date the student takes courses carrying graduate credit applicable to their degree program. Students must be continuously enrolled for the duration of their program.


  • Advisory committee of at least four graduate faculty members, and at least one member of the advisory committee must be from a different department. That member could represent the minor field, if declared. A Representative of the Graduate School will also be appointed by the Graduate School to serve on the committee.
  • HS 601 Professional Presentation Skill
  • Students are encouraged, but not required to take the Horticultural Science core courses
  • As soon as possible after the appointment (or after completion of 18 credit hours of course work), the committee must meet with the student and prepare a Plan of Graduate Work, which must be approved by the DGP and the Graduate School. In addition to the proposed course work, the subject of the student’s dissertation must appear on the plan.
  • Doctoral degrees at North Carolina State University require a minimum of 72 graduate credit hours beyond the Bachelor’s degree.
  • For a student who has a Master’s degree from a university other than NC State, a maximum of 18 hours of relevant graduate credit from the Master’s degree may be applied toward this minimum, upon the recommendation of the student’s Graduate Advisory Committee. Therefore, the minimum credit-hour requirement, in this case, is 54 credit hours.
  • If a student completes a Master’s degree at NC State and continues for a doctoral degree without a break in time, up to 36 credit hours taken while in Master’s status may be used to meet minimum requirements for the doctoral degree. Students cannot take 400-level courses or lower as part of the credit-hour requirement.
  • A graduate course that was completed while enrolled in PBS status at NC State University may be considered for transfer to a doctoral program provided that it is a 500- or 700-level course and that the grade is B or better.
  • All coursework scheduled in the graduate degree classification must be completed prior to graduation.
  • Qualifying Written Examinations in the major and minor fields are scheduled no earlier than the end of the second year of graduate study and no later than one semester before the final oral examination.
  • When all written examinations have been completed satisfactorily, the preliminary Oral Examination is scheduled for admission to candidacy. If student is awarded a graduate assistantship, she/he must complete the preliminary oral exam prior to the start of the eleventh (11th) semester
  • All PhD students are expected to give two formal departmental seminars. The first will be early in their graduate program (usually the beginning of the third semester) and will focus on a review of the literature, proposed research, and research progress made to date. The second will be scheduled in conjunction with their Final Oral Examination.

Additional Requirements


The Doctor of Philosophy per semester graduate tuition and fee rates for North Carolina residents, starting Fall, 2023 is $5,850.13 for 9+ credit hours of coursework. Online courses and the MHS-DE degree option may be subject to different rates. Visit NC State’s Tuition and Fees page for detailed information about graduate tuition and fees.

Financial aid eligibility is determined by the Financial Aid Office. We encourage you to contact your financial aid counselor in the Office of Scholarships and Financial Aid. Criteria for funding are based on academic merit, demonstrated financial need, and enrollment in multiple courses per semester. For additional information, please visit NC State’s Student Services Center website, or call (919) 515-2421. NC State also offers a monthly payment plan.

Students pursuing this degree may be eligible for teaching assistantship funding. PhD students on Graduate Assistantships provided through the Graduate Student Support Plan (GSSP) will receive a stipend, tuition, and health insurance for a specified number of semesters. University fees are not covered by the GSSP, but some faculty advisors may have external funding to cover these costs.

Director of Graduate Programs

Dr. Gina Fernandez
Professor and Director of Graduate Programs
John D. and Nell R. Leazar Distinguished Professor
Department of Horticultural Science
260 Kilgore Hall, Campus Box 7609
Raleigh, NC  27695-7609

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