It is of course still winter. And we had proof of that this past week with temperatures down to -15°C (5°F). But my indoor tomato starters are doing just fine so far. I have a simple, low tech setup. Some trays by a south facing window, and an old desk lamp with a 60 watt bulb to give the young tomatoes just a bit more light to grow. So far, so good. With 50 starters growing in three trays, I probably will have more than I need this year.