Glad I saw this thread. For some reason I thought people kept them a long time. I was wondering what kind of light to keep a bonsai mother under but it seems easier just to replace every 2-3 months, or after 2-3 sets of clones have been taken off. I'll leave learning a new method of pruning and maintaining plants for another time.
I keep my mothers under pretty low light when they are not needed.. I only use somewhere between 30-50 watts per mother. I do this cause I don't want vigor when I don't need clones, But when I do need some I throw it under the 400 MH and watch her BUSH OUT!