The Horticulture Centre of the Pacific (HCP) hosts great Community Education workshops for everyone, from landscape professionals to hobbyist gardeners.
Oregon State University offers a Master Gardener short course series that you can take on demand and access at any time. While most courses are $45, they offer a free Introduction to Urban Agriculture Course
a season-long course that will give you the skills, support & inspiration to fill your kitchen (and your summer) with an abundance of just-picked, nutrient-crammed gourmet vegetables.
Established in 2003, Gaia College offers curriculum in organic land care. Thy have a large range of courses available for home gardeners, landscapers, small food growers, and municipalities and developers
Royal Roads University offers a range of online courses in ecological landscape design, growing food, organic master gardening, rainwater harvesting and management, etc.