College of Knowledge: Abiotic Disorders of Greenhouse Crops

Course Overview

This 4-hour class consists of pre-recorded lectures and is intended for greenhouse and ornamental plant growers interested in learning how insect pests, disease, nutrition, and the greenhouse environment and cultural practices affects plant growth thereby inducing or contributing to the onset of abiotic disorders of greenhouse crops. This course will guide you through the diagnostic process to learn what abiotic factors can cause plant problems causing top growth symptoms (on either foliage, stem or flower buds) or root symptoms.

Michigan State University Extension partnered with University of Kentucky Extension to prepare this course on physiological disorders. The course is instructed with Michigan State University’s online course learning management system, Desire-2-Learn by Heidi Lindberg, Greenhouse and Nursery Extension Educator with MSU Extension. Dr. W. Garrett Owen (University of Kentucky Extension) developed the content. Participants enrolled in this self-paced course will take a pre-test and a final exam to gauge their learning of the topics. Self-assessment quizzes will engage students with the material throughout the course. The course also provides links to additional resources on pertinent physiological disorders of greenhouse crop topics.

Course Content

The 4-hours of pre-recorded lecture and video demonstrations are divided into six units:

  • Unit 1: Introduction to Physiological Disorders of Greenhouse Crops
  • Unit 2: Foliage, Stem, and Flower Bud Symptoms
  • Unit 3: Root Symptoms
  • Unit 4: Substrate and Leaf Tissue Testing
  • Unit 5: Plant Development and Flower Initiation
  • Unit 6: Symptoms Related to Chemical Phytotoxicity and Herbicides

In the first unit we will cover an introduction to physiological disorders of greenhouse crops. In Unit 2, we will cover the physiological disorders that affect the upper growth, including the foliage, stem, and/or flower bud. In Unit 3, we will cover root symptoms that induce disorders in crops. Unit 4 covers methods of substrate and leaf tissue testing in order to help diagnose plant physiological disorders. Unit 5 discusses symptoms that affect plant development and flower initiation including light intensity, photoperiod, ethylene, and other environmental factors. The last unit will cover plant symptoms caused by chemical phytotoxicity and herbicide damage, which can be confused with physiological disorders in crops.

Cost: The cost is $129 per person.

Course offerings: This course is offered once a year in the winter months

    • Registration period: November
    • Course available to students: December-February

Win a $75 gift card: Individuals who paid for the course and completed the pre-test, final exam, and post-course evaluation will be entered into a drawing for a $75 gift card!

Financial Need Scholarships: There are three scholarships available for those that are interested in the course but do not currently have the financial means to take it. Greenhouse growers interested in the scholarship will be able to apply for it upon registering by writing a short paragraph about why you feel you should be awarded this scholarship and how you plan to use the information you learn in your business or professional endeavors. The applicants and winners will be kept confidential. The cost of the course will be $39.99 for scholarship winners. Scholarship winners will be notified after the enrollment period has passed.


Registration for the Winter 23-24 Courses is now closed. This course will be open for registration again on November 1, 2024. To be added to a waitlist to be notified when it opens, take thissurvey. 

Technical Assistance

If you have any technical problems, please contact the Michigan State University IT Service Desk from 7am-12am Monday through Friday and 10am-12am on Saturday/Sunday, any day that the University is open.

  • Phone: (517) 432-6200
  • Phone (toll free): 1 (844) 678-6200
  • Email Web Form

Frequently Asked Questions

What is my username/NETID?

Your username (or NET ID) is the email address you used to create your account during registration (you use the same email address/password for registering and for taking the course).

What URL do I go to for logging into the course?

Go to: You will see the Michigan State University at the top of the page. Login with the email address and password you set during the registration process.

I received a “not authenticated” response when trying to login – what do I do?

A “not authenticated” message is typically an issue with a password not being entered correctly.

I forgot my password – where can I reset it?

If you need to reset your password at any time go to and select the option for "Need help Signing in."