Master Gardeners is a program that is ultimately supervised by USDA through the agricultural/technical universities in every state. Each county in the U.S. has a chapter (or access to a chapter) through its county extension agent.
To become a Master Gardener, you must complete a training class (starting in January each year) and devote 50 intern hours of volunteer service to various projects in the community. Fifty hours sounds like a lot, but we have all found that it goes very quickly and, even better, the more we volunteer, the more we learn about gardening techniques we can use for ourselves, so it's sort of like "free gardening school" once the training is completed. Some of the volunteer opportunities are actually part of the training class.
The training class is very extensive, and the teachers are experts/professionals in botany, biology, environmental science, land management, pest management, water conservation, organic practices, and plant care.
Tuition for the training class is approximately $150.00. Included with the training is a very comprehensive gardening manual, so if you think about it, the training costs about the same as your average college textbook. Many other materials are included at no extra cost
After the first year, if you choose to maintain your status as a Master Gardener, you will need to agree to devote twenty volunteer hours per year and complete eight hours of CE (continuing education) hours, which is easy to do because many workshops are provided.