Question
Have two containers with dahlias in them.  Today was the first snow of the year for us in Michigan.  Several days before this snow and the really cold temperatures - when it was around the 50s or so we brought them inside the house, container pots and all, because they were still blooming beautifully.  Can we continue to keep them growing in the their containers in the house?  We like to keep our house on the cool side, no higher than 65-68 degrees.  I assume they will go dormant by themselves and then we can store them in their containers in the cold frame later in November or in a cool part of the basement.  

Answer
When they are through blooming, let them begin to dry out. Put them in the cool basement, at about 45 to 50 degrees, and only give them enough water to keep the tuber from shriveling up. They don't need light when they are dormant. Cut the stems to six inches.
In the spring, give them some fresh soil, and gradually give more light, and water. When danger of frost has passed, they can go back out side, in a sunny location.