Most gesneriads grow and bloom very well under artificial lights. Fluorescent light setups are available at many department stores and nurseries or you can construct your own. Cool white lamps are adequate, but more expensive daylight types exist that better simulate natural light. Lights should be turned on for 12-16 hours per day. Lights should be hung an average of 8-16 inches above the plants.
Most gesneriads come from humid tropical areas.
To maintain this level during the dry winter heating season, place the pots on a tray filled with damp pebbles or use capillary matting. Also try draping plastic over the light fixtures and growing area to retain humidity. Use this strength every time you water your plants, but once a month use plain water to flush out accumulated salts. Periodically examine the root system by carefully removing the plant from its pot. If the root ball is very tight and overgrown, it's time to repot into the next size pot.