The Gf had some 6500k lightbulbs for her plants. I put 3 of those over the tobacco.If the stems become elongated and leggy as though they are searching for light (it's a good sign they are) you will need to add supplemental lighting. Depending on the temps in your room, a propagation heat mat could also give them a boost by raising temp approximately 10F over ambient. My guess is that you should go ahead and look into lights. I don't use grow lights or bulbs but get by with 2' undercabinet fluorescent light fixtures that are prewired with an outlet plug. They were cheap when I bought them ten years ago, but I imagine all building materials have skyrocketed. If money is tight, you could watch for the plants to become leggy and then get lights or do something different.