2 Answers

While heating the plant room put a pot of water on or near the heat source. I have a wood burning metal stove. I put a pot of water on that and during the course of a day a gallon of water bois or evaporates from the pot. I like to keep my humidity about 25% and I have an accurate meter near my chair so I can see when the room dries out. Below 20% and the room is less comfortable and above 28% the room feels muggy. Maintaining a comfort zone pushes my plants to thrive and I feel comfortable too. Without a wood stove you can use an electric hot plate to boil water. But it is likely you will want to keep the heat up in your plant room as well as the humidity. There are automatic controllers designed for this purpose if you prefer not to get all hands on with the comfort zone management.  These usually cost about $100.00 USD at:                      http://www.google.com/search?q=heat+humidity+controller+prices&btnG=Search#q=h    

I would like to know how you increase the humidity to plants when they are inside during the winter,  Can I sit them in heated rocks.  Buy a humidifer of what