I took in all my tropical plants that were growing outside about 2 weeks ago. Night time temps were just dropping too low. I have reduced the photoperiod inside my grow-shelf to 14 hrs. In another week I will drop it down to 12 hrs. I'll eventually have my light timers setup to the winter sunrise/sunset of the sun here.
You should give your tropical plants a decreased photoperiod. Afterall even in environments they naturally inhabit get less light during the winter months. Plants do react to the time differences. Tropical pings for instance do not truely go dormant. Their winters are drier, and less light. This triggers them to produce the winter succulent leaves. This is also one of the times these pings will flower.