A wee bit (I'm sorry!) of nitrogen will not force a tree into excessive growth so Grandma, and the guy in The World's Fastest Indian would be right, but....... Watso has a case.
I'm semi-retired and found a patch of backyard that had been a banana grove for years (anyone who has had bananas in the yard knows that's where you toss lawn clippings etc) which was an oasis of "soil" in the heavy clay elsewhere. The tomatoes I planted grew like Jack's beanstalk and over-ran everything else I planted. I don't need many tomatoes in the house so just pruned them and persevered but a commercial grower would have ripped them out. Be careful with nitrogen on flowers too.
BTW Watso, a local gardening guru reckons you can cut tomatoes back and make them perennials. I'll try it.
