QUESTION: Should I cut dead leaves off my tomato plant? I’m not sure if they are hurting the plant or keeping it from making more tomatoes.
ANSWER: Whether it is worthwhile to trim dead leaves off your tomato plant really depends on what type of tomato plant you are growing: determinate or indeterminate, also known as bush or vine tomatoes. Here’s the difference between determinate and indeterminate.
Determinate (or bush) tomato varieties will bloom out once and set fruit depending on how many flowers appear, so there is in essence a set number of tomatoes determinate plants will produce that cannot be changed by pruning, for the most part. With determinate varieties, you may wish to prune dead or yellowing foliage below the first set of flowers on the plant.
You can also remove this first level of “suckers,” which grow from the bend where a branch meets the main stem, as long as they’re below the first flower clusters. It is recommended to prune indeterminate tomato varieties more heavily, however, as these plants can set fruit more than once during the growing season, and pruning dead leaves or unproductive foliage away can help encourage indeterminate plants to focus on the development of fruit instead.
If you are growing an indeterminate (vine) type of tomato plant, begin pruning when the foliage underneath the first set of flowers on the plant begins to turn yellow. This usually happens when plants are 12 to 18 inches tall. In addition to dead or yellowing leaves, remove the “suckers” that grow from the crook where a branch meets the main stem of the plant as long as they grow below the first flower cluster.
Later in the season, you may choose to remove suckers growing higher up as well, but be careful not to remove leaves that shade fruits or suckers that have grown especially large, as they can leave damaging wounds. With indeterminate plants, some gardeners recommend also pruning to leave only four or five fruit-bearing branches so that the fruit your plants grow is as large and healthy as possible.