It’s easy to be complacent during the mild days of autumn, but be assured that winter is on our doorstep. If you haven't already, it's time to bring those tender houseplants indoors.
   Nighttime temperatures are now dipping into the forties and our first expected frost is only a few weeks away. Many common houseplants are tropical species and need tropical conditions to survive. Reference books tell us that 50 degrees is an average minimum temperature for good culture. 
    Before bringing plants indoors, give the leaves a good shower, either in the bathtub or with a strong spray of the hose. This will dislodge any critters that may have made a home. A thorough watering will leach out excess fertilizer salts as well as many soil-dwelling insects. Be sure to clip off any dead or yellowing leaves and branches. Some plants may have overgrown their bounds and will require heavy pruning to fit them back into indoor spots. However, be careful not to over-prune flowering plants or you may cut off the next bloom cycle. 
    Other plants may also have become root bound, but fall is not the best time for major repotting. As the daylight hours decline, most plants will enter a period of rest and repotting disturbs this process. However, I will occasionally replace the top one-inch of soil with fresh, a process known as top-dressing. Also, begin to gradually reduce the amount of fertilizer you use. I do not fertilize houseplants at all during the months of December and January.
    Most plants will suffer a bit of shock when brought inside, so don’t be surprised if they sulk a bit at first. Just understand that you are moving them from ideal conditions of high humidity and perfect light to the virtual desert of most heated homes. Misting with a hand-held sprayer will never hurt but unless you do it 50 times per day, it won’t help either. Outdoor humidity levels are very difficult to replicate inside. One option is to run a humidifier, which may benefit people, too. Another is to use pebble trays. Set a large tray of small pebbles or aquarium gravel underneath your plants and keep it filled with water. The evaporation of the water can help raise the humidity levels around the plant.
    One common houseplant that can stay outside a little longer is the Christmas cactus…or as I call it, the Valentine cactus. Cold night temperatures are what trigger these plants to flower. I bring mine back inside after the first frost. And with any luck, I have flowers by February.