Asynchronous online extension classes, in which content is made available on demand, can reach a larger audience, offer more scheduling flexibility, and reduce the strain on limited time and financial resources for extension faculty and staff. In comparison with traditional extension programming (in-person presentations) or online synchronous programming (live webinars), asynchronous programs can require significant time and resources during the initial development stages, including advanced planning and dedicated contributors as well as ongoing information technology (IT) infrastructure and maintenance. The objective of this article is to summarize the development process and inputs needed to successfully develop an online asynchronous extension program based on the authors’ experience developing the Tennessee Master Nursery Producer Program (TMNP). The TMNP is a certificate program for nursery growers in Tennessee designed to improve growers’ long-term environmental, economic, and community sustainability. Developing the online TMNP required three key positions: project coordinator, e-learning specialist, and content developer which spent 473, 401, and 847 hours, respectively, during the development process. Detailed information on development time, requirements, and suggestions for other institutions wishing to develop similar programs is offered.