I thought I read that just putting the soil around them as they grew was not as beneficial as the transplanting. I think maybe it was the actual process of disturbing the roots that caused them to produce more roots. I'll have to research that again, but that is the main reason I have made plans to actually transplant mine a few times, maybe I need to review that and refresh my memory. It is a bad thing to make planting and growing decisions on faintly remembered "facts" I guess. I guess I also need to clarify "larger containers" they aren't all that large, they are just large compared to the small capacity of an egg carton crevice. Anyone here recall reading transplanting helps establish a better root system on tomatoes?