Tomato Type

• Tomatoes fall into two main types -- determinate and indeterminate. Determinate plants generally grow in a bush formation, or stop at a certain height and width. These tomatoes usually don't require pruning. Cutting off stems may prevent blossom growth and the plant only has a limited number of fruiting stems. However, indeterminate, or vine, varieties will often grow continually and can tolerate pruning. Pruning indeterminate tomatoes may help shape the plant and focus energy on several main stems. In particular, pruning on indeterminate varieties usually involves cutting out suckers -- stems that appear between the main stems and the central trunk.
  
  

Tomato Size

• A pruned tomato plant has fewer stems, therefore fewer tomatoes will grow. That means that the energy the plant gains from soil, water and sunlight can go into making larger tomatoes, rather than lots of tomatoes. According to Helene Dillard at Cornell University, a well-pruned plant could produce tomatoes 1 to 2 oz. larger than ones allowed to grow without any pruning. The trade-off is between a large amount of fruit or a larger size for each tomato.
  
  

Pruning Benefits

• Pruning can help keep your tomato plants healthy. For example, pruning lower stems keeps fruit and leaves off the ground, preventing mold and rot. Pruning off stems that tangle or impede the growth of other healthy stems prevents problems when the fruit grows. Snipping off the suckers keeps your plant neater and easier to train along trellises or twine. Plants grown indoors or in a small space may benefit from pruning to keep the size manageable.
  
  

Drawbacks

• Overpruning puts stress on a tomato plant. In turn, this reduces the plant's resilience, increasing the risk of conditions such as blossom end rot. Similarly, leaf roll can affect heavily pruned tomato plants. This condition causes the tomato leaves to pull up at the sides and start to wilt. Pruning too many leaves from a fruiting plant can expose tomatoes to strong sunlight. This can cause sun scald -- a form of discoloration and damage to the fruit skin.