Tomato plant care often involves managing small auxiliary shoots known as suckers, which emerge naturally as part of the plant’s growth cycle. If left to grow, these shoots have the potential to develop into new, fruit-producing stems. Deciding whether to remove these structures, a practice often called pruning or “suckering,” directly influences the plant’s overall shape, fruit production, and health. This management technique redirects the plant’s resources. Ultimately, the decision to remove a sucker depends on the specific tomato variety and the gardener’s harvest goals.
Defining and Locating Suckers
A tomato sucker is a vegetative shoot originating from the axillary bud, located in the “axil” of the plant. This axil is the precise point where a horizontal leaf stem connects to the main vertical stem. Suckers grow at an approximately 45-degree angle, distinguishing them from the main stem and the leaf branch.
When a sucker first appears, it is a small, tender shoot that can be easily pinched off. If left to mature, this shoot rapidly elongates, developing its own leaves, flowers, and eventually fruit. It effectively becomes a secondary main stem, often making it difficult to distinguish from the original stem later in the season.
The axillary bud is pre-programmed to produce a new branch, leading to rapid growth. In warm weather, a small sucker can grow into a substantial secondary stem within a week or two. Identifying these shoots early, when they are less than a half-inch long, is necessary for easy removal.
The Impact on Plant Growth
The primary reason for removing suckers is to manage the plant’s energy allocation. Each sucker competes with the existing fruit and the main stem for water and nutrients. Allowing numerous suckers to grow results in the plant prioritizing vegetative growth, diverting resources away from developing fruit. This diversion often results in smaller, less uniformly sized fruit and can delay the overall ripening time.
Increased foliage density from unpruned suckers compromises plant health by limiting airflow within the canopy. Poor air circulation creates a humid microclimate, ideal for fungal pathogens like early and late blight. Removing suckers thins the plant, allowing more light penetration and speeding up the drying of leaves after watering. A less dense canopy also simplifies pest inspection and harvesting.
Techniques for Removal
The decision to remove suckers depends fundamentally on the tomato variety, classified as either determinate or indeterminate. Determinate varieties grow to a set height and do not require sucker removal, as suckers contribute to the overall yield, and pruning can reduce the total fruit set. Indeterminate varieties continue to grow and produce fruit until frost, and these types primarily benefit from regular suckering to control their vigorous, vine-like growth.
Pruning Indeterminate Varieties
For indeterminate plants, the goal is to train the plant to one or two main stems, and all other suckers should be removed. When a sucker is small, typically under a half-inch, it can be removed by simply pinching it off with the thumb and forefinger. This method minimizes the wound to the plant. If a sucker has grown larger, exceeding the thickness of a pencil, use clean, sharp shears to make a precise cut close to the main stem.
Always use sanitized tools, wiping blades with rubbing alcohol between plants to prevent the spread of any latent diseases. The optimal time for removal is during the morning on a dry day. This allows small wounds to heal quickly and reduces the opportunity for pathogens to enter the plant. A general rule is to leave the sucker directly below the first flower cluster, as this sucker is typically the strongest and can grow as a secondary fruit-producing stem.
Using Suckers for Propagation
Instead of discarding removed shoots, suckers offer a straightforward method for cloning the parent plant, quickly producing genetically identical new plants. This technique, known as vegetative propagation, leverages the tomato plant’s ability to easily produce adventitious roots. A healthy sucker between four and six inches long and without flowers is an ideal cutting.
To root a sucker, strip away the lower leaves, leaving only the top two or three small leaves. The cutting can be placed in a jar of room-temperature water, submerging the lower third of the stem. Roots typically form within seven to fourteen days; changing the water helps maintain oxygen levels and prevent rot.
Alternatively, the sucker can be planted directly into moist, well-draining potting soil, burying the stem up to the remaining leaves. This method bypasses the water-rooting step, resulting in a quicker transition to soil growth. Propagating suckers can extend the harvesting season by providing late-season plants that produce new fruit until the first frost.