spider mites.I use safers insect soap& it gets what needs to be gone pretty well.
did you remove the paper wraps they stick those pots in?sometimes nursey stuff has critters travel.I try to remeber to keep away from ine a few days to be sure are clean.most times I'll soak my trades a bit in a bleach water solution to zap some of that.also living up north your air is dryer they will hold over to
spring better if in a cooler room in house.when I lived IndplsI use to keep them set by back slideing glass door,but were spoiled.I used a grouping of
plant lights& adjusted their angle all the time.I later would store them in their pots on their sides under deck against house under hay,would lay 2-3 of them mulch bags across with a few bricks and was removed out in May.I'm glad to NOT go through all that now.
you should check kings mums out& they have some now that will withstand your temps grown in ground
http://www.kingsmums.com/