I dont' think so. After a while you will let them cascae.
Youn can even manage to keep them under 4 feet without pruning. Tomato plant is not like a tree to keep growing up. If the branches
are not supported they will just cascade or even fall on the ground.

Agree. Stake or cage height doesn't determine or even limit the height of the plant. Once it reaches the top of its support it just drapes back down quite normally and does just fine. And 5-6' is the normal size for most typical tomato supports. No one expects to have to use a ladder to pick their tomatoes. ;)

There is no need whatsoever to pinch off the plant when it reaches the top of whatever support you use. All that would do is limit your production.

Dave

Thanks, Cyrus gardener and Dave. I'll leave them alone then, and if they get tall, just let them hang. I'll be using the much-maligned 'stake and flimsy wire cage' support system for this year. I am planning on re-doing my clematis supports with cattle panels (if I can find some). Once they are done, I'll look into some of the wonderful ideas for tomato supports I've read about on this forum.
Thanks again.
Judith

hmm, each area is different. Sounds like you are in a humid area. (never been to montreal) I say prune to keep excess humidity from rotting the fruits by allowing more air flow. True on the height, train it horizontal maybe. Enjoy and keep us informed.

Judith
Pruning the top will not shut down the production so long as the suckers have not been pruned. The suckers will continue to grow and produce and grow suckers of their own. These suckers are usually easier to train to grow horizontally. In 5b you will not have a mid summer slump, (this is when the plant grows it's fastest but isn't setting blossoms), or a real long season and 5 feet may be a sufficient height. In my zone I cut the tops at 7 feet around mid season and I prune all my suckers. The plants cease to produce new fruit but by this time my later set will be about half way up the trellis in anticipation of the drop in temperature. Keep in mind that tomatoes are a perennial native to Peru and grown in other climates as an annual, Therefore you will get more accurate information on growing methods in your own climate zone. I hope I have been of help.
~Ken~

Pruning the top will not shut down the production so long as the suckers have not been pruned.

True if using cages. Unfortunately when one is using stakes as Judith is, many of the suckers likely will have been pruned as that is the standard practice with stakes. It is difficult to effectively stake an indeterminate variety without aggressive pruning. If using determinate varieties then the question is moot. So removing the growing tip will reduce the plant's production.

Judith - rather than going with a single stake and one of the 3 ring cage things consider a 5 foot CRW cage or a stake tripod (3 stakes tied together at the top) for better support.

Dave

Judith

Here's a tripod construction, and if you aren't growing a gazillion tomatoes, it is definitely doable, just an expansion on the stake to make it more stable and attractive.

Thanks so much everyone for all your comments and help. I am pretty new at vegetable gardening, as you can probably tell LOL
Tedsfarm, yes, Montreal can be humid but last summer was not, just a lot of clouds, rainy and cool - wasn't a good year for tomatoes.
Ken, Dave and Anney - I was actually going to use a combination of supports - I have a few of those expandable tomato rings that are attached to a stake and into the ground, and 4 of the garden variety cheap tomato cages that I was going to secure to the ground with my son's old hockey sticks (so not really pruning to the stake, but rather growing to fill out the cage - the stake just keeps it from falling over). I am probably going to rig up something that is more solid next year, but my budget will only allow the clematis supports (cattle panels) this year. I have a LOT of clematis.....I am also not sure how the community garden thing will work out - next year I will have a better idea and will then feel more comfortable investing in those new, stronger supports.
Maybe I will make a few tripods with some of those old hockey sticks too, and then I can grow them along an adjoining stake (like in the photo) as suggested. As long as I don't prune the suckers too much (or at all?), I can tip them without losing a lot of production, right?
Judith