Trimming tomato plants is a common practice among gardeners, though the necessity depends entirely on the specific variety being grown. Most home growers benefit from strategically removing certain parts of the plant to manage growth and improve fruit quality. This physical manipulation, often called pruning, is the removal of non-essential foliage or stems to redirect the plant’s energy and resources. Understanding the plant’s natural pattern of growth is the foundation for deciding whether, and how much, trimming is needed.
Understanding Tomato Growth Habits
Tomato plants grow in two primary ways: determinate and indeterminate. Determinate varieties, often called “bush” tomatoes, grow to a fixed height and size, usually between two and three feet. They produce the majority of their fruit simultaneously over a short period, and their growth stops once fruit sets on the terminal buds. Determinate tomatoes require very little pruning because trimming vegetative growth can significantly reduce the potential yield. Indeterminate varieties are vining plants that continue to grow, flower, and set fruit until the first frost. These plants can easily reach heights of six to twelve feet and require aggressive trimming and structural support to remain manageable.
The Specific Parts to Remove
The most targeted parts for removal on indeterminate plants are the side shoots known as suckers. A sucker is a small shoot that emerges from the axil, the V-shaped junction between the main stem and a leaf branch. If left alone, these suckers will mature into full, fruit-bearing stems, creating a dense, sprawling bush. Removing suckers redirects the plant’s energy into the existing main stem, leading to larger fruit.
If a sucker is small, less than half an inch long, it can be easily pinched off with your fingers. For larger suckers, which are thicker than a pencil, clean, sterilized pruning shears should be used to prevent damaging the plant or spreading disease.
Removal of lower foliage is also important, especially on the main stem below the first fruit cluster. These older leaves are often the first to yellow and are susceptible to fungal diseases because they are close to the soil. Soil-borne pathogens, such as blight, can splash onto these leaves during watering or rain. Removing the bottom leaves creates a clear stem base, reducing the risk of contamination and improving air circulation near the ground.
The Purpose of Strategic Trimming
Pruning is performed primarily to manage the plant’s resources and control the spread of disease. Removing dense foliage, especially from the interior, significantly improves air circulation. This reduces humidity within the plant’s canopy, allowing leaves to dry more quickly after rain or irrigation. A drier environment is less favorable for the development and spread of fungal issues like early blight.
The removal of suckers and excess leaves redirects the plant’s energy toward fruit development. By limiting new vegetative growth, the plant concentrates its resources on sizing up the tomatoes already set on the vine, resulting in higher quality fruit. This concentration of energy contributes to earlier and more uniform fruit maturation. Leaf removal also allows more sunlight to penetrate the canopy and reach developing fruit clusters, which helps speed up the final ripening process.