Heated greenhouse tables serve two main purpose on the small market garden veggie farm. First, it offers a place with a fairly constant temperature to ensure high germination rates. Not too unlike the Sweat Box Germination Chamber (http://farmhack.net/tools/sweat-box-germination-chamber), However, this tool allows us to continue growing the seedlings under optimal conditions until they get a bit stronger. Secondly, we can get some onion plants out to the greenhouse to free up room in our seedling room. We start onions and greenhouse tomatoes under lights in the basement, then move them out to the greenhouse when we are ready to start heating the greenhouse/nursery.