Wow, transplant an adult tomato plant? My first guess is that the roots would spread almost as wide as the vines would if they were sprawling. In any event, I would expect the roots to spread 3-6 feet in every direction, and at least 2-3 feet down if the aerated layer of soil goes that deep. Maybe a plant only 3 feet tall would have a smaller root ball.
If the roots spread that far, wouldn't you need a backhoe to move it?
Would it survive losing half of its root ball? Or only drop all the fruit and flowers and start over from scratch?
Someone with experience transplanting adult tomatoes might know better, but my guess is that it would be an experiment to discovering whether an adult tomato can survive severe root pruning and still produce fruit in the same year.
