If you feel comfortable with the air temperature - your plants probably will too. Most houseplants enjoy the same temperatures we live in.
Relative humidity is another matter all together. In the winter, when central heating takes over, houseplants struggle because the air tends to be extremely dry. Indoor plants are tropical creatures and insist on adequate humidity levels.
Most indoor plants are happy with the same temperatures we live in.
It's easy to feel the temperature in a room by simply standing in it. Understanding temperatures from a plant's perspective isn't quite that simple however.
Temperatures in a typical room can vary a lot. Some spots get more sun than others. Other areas get more (or less) heat or air conditioning. Each of these small spaces in the room are called "micro-climates".
For example, temperature close to a window can be much different than the temperature in the room. When the weather outside drops below freezing in winter, the temperature in your windowsill could be in the 40's. On a hot summer's day the temperature that same window can soar to 120 degrees or more!
A good way to identify micro-climates is a "minimum/maximum" thermometer. It not only shows the current temperature and humidity, they also record the highest and lowest temperatures and humidity levels over time. We use them regularly.
Humidity is moisture in the air. Most indoor plants come from the tropics and they welcome humidity. The ideal humidity range for indoor plants is in the 40-70% range.
Providing adequate humidity can be a challenge in winter.
Humidity levels are closely tied to air temperature. To help maintain higher humidity during the winter, turn down the thermostat. Your plants will gladly trade cooler temperatures for the hot, dry air from the furnace. Don't worry about your plants getting cold - you'll be chilly long before your plants will.
In the summer, houseplants plants enjoy the natural, warm, humid air from outside. Air conditioners not only cool the air, they also remove moisture, which lowers the humidity. Plants hate cold drafts from air conditioning!
Grower Tip: Don't confuse humidity and water in the pot. Humidity is moisture in the air. Watering your plant more to compensate for dry air is a sure way to kill it.
1) Lower room temperatures. Cool air holds moisture better than warm air. As long as the root zone stays warm, air temperature can go as low as 60 degrees.
2) Put your plant(s) on Humidity Trays. Moisture in the air increases as water in the tray evaporates.
3) Invest in a humidifier.
Unfortunately, misting plants to increase humidity doesn't do much because the effects of misting are short lived. Unless you mist your plant every 30 minutes - around the clock - misting won't help.