I've had my pencil cactus on the patio all summer and it's doing great. The nights are dipping into the mid 30's now and 60's in daytime. How should I treat my plant? I brought it in last night; should I put it back out this morning? It's still rather cool and won't warm up for a few hours, but I won't be home to put it out later.
Once overnight temperatures start dropping into the 40's F, it is time to bring it in. If the plant is small enough and you are home to bring it indoors and outdoors, that is fine for some plants, but most plants do not like too much environmental change. You would be better off simply bringing it indoors for the winter, and then outdoors in the spring when the overnight temperatures are in the 50's F.