Depending on wht way you want to go with them, you could keep them in the window or where ever you have them under the natural sunlight. If you chose to keep going with the sunlight, just make sure your not freezing them out. You can buy a themometer at the dollar store or wal mart, pot likes the temp between 70 and 75 degrees celcius. If you find its too cold, move them to a different warmer location near a window or buy a small space heater and adjust your temp as needed. As well keeping them in the natural light may take them a bit longer to grow as you like. And it's hard to keep a proper light cycle, that being said what light cycle do you have them on now? Just whatever the sun decides to do? But if you decide that lights are the way to go, we are using CFL's and eventually a HPS. The bulbs can be boughten at wal mart or zellars. And for the fixtures we went to a thrift store and bought and took apart lamps.