Great question, the same thing happens to me in New Jersey

Often discussed but I don't know if any of the previous discussion are still available via search or not. Search 'pinching', 'pruning tops', 'plants too tall', etc.

So just my opinion - no, since it defeats the whole purpose of growing indeterminate varieties that are just doing what comes naturally to them. Nothing says you have to stake them to 10-12' tall and very few folks do so with no problems. But if you want short plants, grow determinates or so-called semi-indeterminates. ;)

thus allowing more production into the lower 2/3rds of the plant

You are assuming that would happen - new growth and even production in the lower 2/3 of the plant but it really doesn't or only does so minimally as that isn't the nature of indeterminate vines. The circulation to those lower branches has already been sealed off from the plant circulatory system.

Some varieties will send up new growth from the root ball if severely pruned back to within 1-2 feet of the ground and if the weather allows. But unless you have an exceptionally long growing season - and you may in zone 9 (but not in NJ) it doesn't have time to bear fruit. So what production you would have had otherwise is lost (assuming weather even allows for pollination.)

Like I said - JMO.

Dave

I have pinched new growth back starting 5-6 weeks before frost. That is the latest any fruits can ripen from new flowers. The initial immature leaves grow out (adding a foot or so to the plant) leaving the rest of the nutrients to go to the fruit rather than new grow. I have not compared flavor or fruit size to non topped plants, but it made my garden less messy with over grown plants and reduced the problem of end of year green fruit.

I've only trimmed tomatoes that got too tall upstairs or too leggy this winter in the GH. But I do it early before they start blooming.

Mike

FWIW, I attended a talk by a professional organic gardener. She said that topping off indeterminant tomato plants late in the season stops them from growing and producing more flowers/fruit, and redirects the plant's energy to ripening the existing fruit. If you're at a point in the season where new fruit is not likely to ripen, it makes sense (to me) to top off the tomato plant to increase the likelihood that the fruit on the rest of the plant will ripen.

Of course this does stop the plant from growing so it's not something you would ever do early in the season.

" Of course this does stop the plant from growing so it's not something you would ever do early in the season "

Topping plants early in the season does not stop new growth. In fact it may get twice the amount of new growth from suckers.