Abigail, yes you need humidity but other things are far more important such as light, media, healthy roots and watering.
Low humidity during the heating season is just a fact of life growing plants indoors.
Misting is very over rated!! It has no real effect at all on successful plant growth. You can only do so much.
There are better ways to increase humidity other then misting. Dedicate a room as a 'plant room'. Close it off and put in a little humidifier. Grow under lights and use a little 'tent like enclosure'.
