Looking at your profile, I'd say you're plenty of talented and experienced and don't really need a course like that. In my experience, courses are good for high concentration for beginners or when you need the undivided attention of an expert about something really specific and esoteric. If its something in the middle I'd recommend a trip to the library or poking around youtube.
"Gaining a basic idea of gardening" you say. I'd strike up a conversation with a little old lady at farmers market. They'll probably talk your ears off and melt your brain with all sorts of information.
