Posted: 06/06/2016 at 13:41
There are two types of tomato plants, cordon (indeterminate) and bush (determinate). Each variety belongs to one or other of those groups, e.g.. Gardeners' Delight is a cordon, Tumbler is a bush.
Cordon tomatoes are best grown upright,supported with canes. To keep them in trim, you pluck out side shoots as they develop. Bush tomatoes just creep or tumble on the ground or in baskets or beds, and don't need to be nipped out.
Later in the season, it makes sense to stop the. plants by nipping out the leading shoots, so that the plant doesn't waste energy producing fruit that will never ripen. Cordons should be stopped once about 4 or 5 trusses of fruit have appeared. I also stop my bush tomatoes in late summer or early autumn, otherwise they go on and on making marble-sized green tomatoes.
So you have to know which varieties you are growing, and whether they are cordon or bush types. If it's too late to identify them, you'll just have to do whatever seems easiest - you'll still get some tomatoes. If you know the names of the varieties, google them for details, to find out how best to grow them.