I dont let my temp go past 50. They can survive at lower for short amounts of time, but 50F is considered the safe cutoff point.
Alot of people replant there plants with an organic soil, or even use layers of sand, and hydroballs to help the water drain out. I personally do nothing the the plants other than spray them with hot water after I but them.(I constantly kill sheffleras from over watering though) I then Go to my backyard and pull up small foliage like grass, and clover, and shamrocks and such, and put that on top of the exposed soil. That makes them unable to eat the dirt. But most people just use river rocks to cover it. If they eat the dirt, they can become impacted and die. It happens when they shoot a feeder off it, and it happens. My outside collected vines and branches also just get a blast of hot water, and into the cage they go.