Looking good, Mary!
I'd forgotten you have a basement. That would be a good place to put some grow lights instead of the garage.
How deep are your basjoo corms? If you go a foot, you shouldn't even have to do anything except mulch a bit. If you spend a couple bucks at Menard's (I think that's what you have up there) and get some Sonotubes (sp?), you can put them around the plants and fill with sawdust or leaves or something as an insulator too.