Determinate tomatoes need no pruning other than removing all suckers below the first flower cluster because pruning won't affect their fruit size or plant vigor. If you do any pruning at all above the first flower cluster on determinate tomatoes, you'll only be throwing away potential fruit.

What happens if you don't prune indeterminate tomatoes?

Indeterminate types can be pruned simply by 'rolling' out any young shoots that develop between the leaves and the main stem. ... Also, unpruned tomatoes are much more prone to wind damage because the large shoots can snap-off and split the main stem, resulting in the destruction of the entire plant.

Do you pinch Determinate tomatoes?

Determinate tomatoes set the bulk of their crop at one time. ... Avoid pruning tomato determinate varieties or pinch back only suckers that appear below the first flower cluster, or you will reduce your yield. Indeterminates, on the Page 4 other hand, will continue to grow and set fruit until frost.