Hi Mother Raphaela, as I understand it, some of the carnivores go into a natural hibernation during winter. So even in a terrarium some will naturally be not actively growing. But there are some types that are not affected by the seasons.
I found this website..it seems their instructions are easy to follow. You may want to read through and see if it is something doable for you. :
http://www.stormthecastle.com/...
