Herbology is the study of magical plants growing throughout the Wizarding world. Classes are most often held in one of the three greenhouses located on Hogwarts, and for the majority of the time they involve hands-on activity. Students are instructed in the cultivation of these plants as well as their benevolent and malevolent properties. Lessons in Herbology run from the first year all the way up to the seventh year. They are a requirement only up until the fifth year.

First year: Students are introduced to the art of cultivation. They are taught the basics of what most magical plants require for growth - be it sunlight, water or a dead frog every now and then. They are given seeds to plant in the greenhouses, and throughout the growing season they study and tend the projects.

Second year: Study continues on cultivation, including more complex and more dangerous plants - Mandrakes, for example. The focus of the lessons remains upon plants native to Western Europe.

Third year: Plants native to other regions of the world are studied, some are grown throughout the year. Students are now taught the finer points of growing plants - the beneficialities of pruning, fertilising and playing music to soothe a cranky conifer.

Fourth year: In addition to merely growing, students are taught to identify and treat common diseases, fungi and parasites that afflict magical herbs.

Fifth year: Diagnosis and treatment of ailments continues, alongside the culture of complicated and rare plants.

For the OWLs: For their exams, students must be able to demonstrate their knowledge of horticulture by listing the various properties of herbs, both benign and malignant. They will also be required to identify the various diseases infecting several plants, and they will be given projects earlier in the year to have prepared by the deadline.

Sixth year: Those students who continue to pursue the study of Herbology are granted space in one of Hogwarts' gardents to cultivate their own plants. More space is granted in the greenhouses, for those who choose to take up cultivating more exotic species.

Seventh year: Students are expected to conduct experiments in breeding or grafting species of plants, with the intent of attaining stronger, healthier specimens. They are also expected to maintain their own gardens.

For the NEWTs: For their NEWTs, students will have to have prepared - by the end of the year - five full-grown specimens. Through written examination, they must describe the properties of plants, their common afflictions and their native habitats.