Pruning is a foundational practice in successful tomato cultivation, directly impacting both the health of the plant and the quality of the harvest. Strategic removal of unwanted growth, specifically secondary shoots known as suckers, is a highly effective way to manage the plant’s form and energy expenditure. By controlling the overall plant structure, gardeners ensure that resources are directed toward developing robust stems and larger, better-flavored fruit. This focused approach maximizes the yield potential of the tomato season.
Identifying Suckers and Their Location
A tomato sucker is a vegetative shoot that develops in a specific location on the plant. It emerges from the axil, the point where a lateral leaf branch connects to the main, vertical stem. This growth point forms a “V” or crotch.
If left unchecked, the sucker grows into a secondary main stem, eventually producing its own flowers and fruit. While this results in more total fruit, numerous main stems create a dense, bushy structure. This energy drain often leads to smaller fruit size and late-season production from secondary stems.
The Rationale for Removing Tomato Suckers
The primary reason for removing suckers relates to the efficient allocation of the plant’s energy resources. Every developing sucker requires photosynthates, the sugars produced through photosynthesis, to fuel its growth. When a plant supports multiple stems, this energy is divided, reducing the resources available for the main stem and the fruit it is setting. Eliminating these competing growths redirects energy toward fewer, higher-quality tomatoes, resulting in larger size and improved flavor concentration.
A secondary benefit is improved air circulation within the plant canopy. Denser foliage traps moisture, creating an environment favorable for fungal pathogens, such as Early Blight or Septoria Leaf Spot. Creating an open structure reduces humidity and allows foliage to dry faster after rain or dew, which helps prevent common tomato diseases.
Step-by-Step Sucker Removal Techniques
The method for removing a sucker depends on its size, emphasizing the need for consistent, timely pruning. Small suckers, typically under two inches in length, are easily removed using the “pinching” method. By placing the thumb and forefinger at the base of the shoot, the gardener can snap it off cleanly and quickly.
Pruning should be done on a dry day, as the resulting open wound will heal faster and reduce the chance of pathogens entering the stem. For suckers exceeding four inches, pinching is not recommended because the tissue is tougher. Attempting to break it can tear the skin of the main stem, creating a large, ragged wound that is slow to heal and leaves the plant susceptible to disease.
Larger suckers require the use of sterilized pruning shears or sharp scissors for a precise cut. The tool should be wiped with a disinfectant, such as isopropyl alcohol, especially when moving between different plants, to prevent disease spread. The cut should be made cleanly and close to the main stem. A technique known as “Missouri Pruning” can be employed for very large suckers, where only the growing tip is removed, leaving the first leaf attached. This practice reduces shock to the plant and promotes faster healing of the wound.
Pruning Differences for Determinate and Indeterminate Varieties
The decision of how aggressively to prune depends on the tomato variety’s growth habit, which falls into two broad categories. Indeterminate tomato plants are vining types that continue to grow, flower, and set fruit continuously until frost. These varieties benefit from aggressive sucker removal, which manages their sprawling growth and focuses energy on a single or a few main stems.
Determinate varieties, often called “bush” tomatoes, grow to a predetermined height, typically setting all their fruit in a concentrated burst over a few weeks. These plants naturally limit their own growth and require minimal to no sucker removal. Removing suckers from a determinate plant can reduce the total yield and expose the developing fruit to sunscald, as their foliage is needed for protection. A general rule for all varieties is to remove any suckers or leaves below the first flower cluster, as this improves air circulation near the soil line and prevents soil-borne diseases from splashing onto the foliage.