It will be a race to see if increasing daylight hours will keep up with your sprouting tomatoes. Recommend as soon as they get another set of leaves, up-pot them and bury them up to the leaves. The stems will grow roots and they won't fall over.Also recommend Jobe's organic tomato and vegie fertilizer mixed into the transplant dirt and subsequent regular feedings. Tomatoes are such eager growers and you never know when you'll hit a jackpot. It's the random reinforcement factor. Call me and I'll share lessons learned from countless tomato seasons under the Alaska sun...or lack thereof.
I just picked up a bag of that Jobe's fertilizer at the garden store--it looked promising; glad to hear it's a winner. Just waiting for that first set of real leaves and then the tomatoes will get rehomed...they just look pretty pathetic and spindly right now.