Larry, I'm pretty sure that tomatoes don't have a "taproot." Carrots are a taproot. Tomatoes don't grow roots like a carrot. There's always a possibility that I'm mistaken about this, but I don't think so.
Anyway, I still really don't know about planting the tomatoes and then just adding dirt as they grow, as opposed to transplanting to a new pot with more dirt. I do know that when I transplant I plant the seedlings deeper than they were growing and roots form all along the submerged stem, and when I plant them out in the garden I also plant them deeper. Anything under the soil grows roots, and I don't think the stem needs to be injured in any way for that to occur. Those tomato stems just WANT to grow roots, in fact there are often "vestigial" roots that start forming along the stem even above ground.
I'm looking forward to trying this out ...
