Is it true that if a tomato plant is let to grow too much that it produces less fruit? I would think that since it uses so much energy creating more leaves and branches that it would have less energy for the fruit. Is that the case?
Well, they do grow too many leaves & branches if left to their own devices. You control this by suckering - which is pinching off the smaller stem that shows up right where a true branch and the main stem are.