Are you talking about germinating the seeds, or growing the seedlings?
After I plant seeds in pots or 6-packs, I put them in trays,cover them with clear plastic covers or bags, and put them on top of my refrigerator to germinate. It's just a little warmer up there, and the plants like bottom heat. When the plants emerge, the seedling go down in the basement under flourescent lights-48" shop lite type fixtures one cool white bulb and one warm white bulb. When the bulbs wear out, I'll probably get full spectrum bulbs. The plants should be only a few inches below the lights to start- and either raise the lights or lower the plants as they grow. I use a plug in timer and leave the lights on 12 hours a day.