Above ~40*F, they will break dormancy. Sooo, you will also
need good light (and water), otherwise you will see a lot of
tender 'spidery' growth.
George (NJ).

If that happens and you do see leggy growth, wimpy leaves, etc., no big deal. Just prune that stuff off before placing your trees outside in the spring. Better off starting over, as if the trees are coming out of dormancy, than have to deal with the above. This happened to me this past season and the pruning did some of my trees a world of good!