I bought a cute japanese maple in a low pot (not a true bonsai, but one that may have some potential) It was an impulse buy. We enjoyed it all summer. I know that these trees are not hardy in Edmonton. In the fall once it had dropped all it's leaves I put it in a shed, over a barrel of water then put foam pad around it, and topped with a garbage bag. Temperatures inside this have been -3 to +2 My idea is to keep it here long enough to satisfy it's chilling requirement, then to bring it out into our conservatory (brightly lit, but seldom over 14 C in winter.) My notion is that this would give it 'spring' it would break bud, and be an inside plant until it can go back out on the deck. How long does it need to be cold before bringing it in?