Can anyone offer suggestions how the out of season blooming of plants is induced. When you see horticultural exhibitions it is pretty clear that those exhibitors have ways to manipulate the timing to ensure that their plants are at optimum for the show. So, what do they do ?, is it temperature, light, chemical or what ?.

I hasten to add that I have no intention of participating in a show, just very curious by nature.

No doubt there are various tricks specific to a given type of plant, but there must be other methods of a more general nature.
I know that there are times when every gardener sees something coming into bloom that should not, but how does that relate to deliberate manipulation, can we learn anything from what seems to happen spontaneously, or can the methods used by exhibitors help explain those odd exceptions to routine.

Tim.