Basement dormancy?

I live in Chicago. For the dormancy period can I keep my young vft's in a non-heated basement? It doesn't get as cold as the frig but it's all concrete. Also how will I know when the vft's are going into dormancy?
I think that's what I may end up doing, but then again, I haven't done it before either.

It may not work either. The only window in my basement where it could get moderate light is pretty close to the boiler.

Anyone else know?