My plants go into the fridge in the late fall. late October or early November.
whenever the nighttime temps begin to seriously fall below freezing. (32F, zero C)
They stay in the fridge all of November, December, January,
and they usually come back out in Mid February..Valentines Day. 3 and 1/2 months dormancy.
but..Mid-February is still the dead of winter here! still far too cold outside.
So they sit indoors in front of a bright window to slowly come out of dormancy.
then, by April or May, they can go back outside for the season..
they remain outside ALL Summer, and then into Autumn..
I keep them outdoors all through August, September and into October, as days and nights
gradually fall into the 60's, 50's, 40's.. (15..10...5C)
I wont even consider bringing them inside unless its going to fall below freezing
or if there is a heavy frost forecast for overnight.
This way, nature creates a natural dormancy for me!
I dont have to do a thing about "making them go dormant"..
they go dormant naturally through all of late summer and into autumn..
then, by the time they are ready for the fridge,
they are already fully "asleep" and are ready to continue that sleep in the fridge..
Please note that the fridge does not cause
it simply maintains
the dormancy that was already started naturally by keeping the plants outdoors all season..the plants need to be already dormant
before they go in the fridge.