Pj,
keeping VFT's indoors in a terrarium is very problamatic when it comes to dormancy..
because the plant gets none of the natural "cues" that its time to begin going dormant, like plants grown outdoors get..
In August and September, the amount of daylight begins to shorten, and temps begin to fall..
this "tells" plants that autumn is coming, and its time to begin preparing for dormancy..
the plants begin to slow down, and begin to enter dormancy on their own gradually over several weeks/months...
by October, the plants are usually fully dormant, and can just stay outside if your climate allows that, or they can go in the fridge if your winter climate is too warm or too cold..
your VFT, being in a terrarium, has no clue that it was supposed to enter dormancy several months ago, because it got no natural light or temperature cues..
so it isnt "ready" to go dormant..
you have two options, risk shocking the plant by putting straight in the fridge..it might die.
or..just let it continue growing through the winter and do nothing about dormancy..
it will die eventually.
neither option is ideal..if you put it in the fridge it *might* die..its a shock to put a plant into dormancy when it isnt ready for it.
but..if you do nothing, it WILL die eventually if it gets no dormancy..but it could still last another year or two..
so..the fridge dormancy has maybe a 50/50 chance of success..but if it works your plant will be better for it, and can live indefinately..
doing nothing, giving no dormancy, has a 100% chance of death..but slowly over time.
this is why im against growing CPs that require dormancy indoors, in terrariums..it simply doesent work when its time for dormancy..growing the plants outdoors is FAR better..
here is the way I do Fridge dormancy:
Fridge Method
Scot