Tomato plants are vigorous growers that, when left unmanaged, can quickly develop into dense, sprawling bushes. This growth requires intervention to ensure the plant directs its energy toward producing a high-quality harvest. The practice of removing excess vegetative growth is known as pruning, a common maintenance task for gardeners. Understanding the specific structures that contribute to this growth is the first step in effective tomato plant management.
Identifying Tomato Suckers
A tomato sucker is a secondary shoot that emerges from an axillary bud, located in the “V” or crotch formed between the main stem and a leaf branch. This location differentiates a sucker from a standard leaf branch or the main leader stem. If not removed, the sucker rapidly develops into a full-sized branch with its own leaves, flowers, and fruit, often producing secondary suckers and leading to a complex and tangled plant structure. Gardeners can easily spot them by tracing a leaf branch back to the main stem and looking for the new shoot growing out of that junction. Removing these shoots while they are small, ideally between two and four inches long, prevents them from diverting too much energy from the primary growth.
Why Pruning is Beneficial
The primary reason for removing suckers is to manage the plant’s energy distribution, ensuring resources are directed efficiently toward fruit development. Suckers function as additional stems that compete for the plant’s photosynthates. By limiting the number of growing tips, the plant concentrates energy on the remaining fruit clusters, resulting in earlier ripening and larger individual tomatoes.
Pruning also improves air circulation within the plant canopy. Dense foliage traps moisture, creating an ideal microclimate for fungal and bacterial diseases. Removing excess suckers helps the remaining foliage dry quickly after rain or irrigation, preventing common issues like Early Blight and Septoria leaf spot. This thinning also allows better light penetration, encouraging fruit set and ripening.
Proper Removal Techniques
The method for removing a sucker depends on its size. When suckers are young and small—less than the diameter of a pencil—they can be easily pinched off using the thumb and forefinger. This technique breaks the tender stem cleanly at the axil and allows the wound to heal quickly with minimal stress. Pruning is best performed on a dry, sunny morning after dew has evaporated, allowing the small wounds to dry before evening moisture sets in and lowering the risk of disease transmission.
For suckers that have matured past the pencil stage, using a clean, sharp tool, such as pruning shears, is necessary to avoid tearing the main stem. If cutting is required, the tool should be disinfected between plants, especially if disease is present, using a solution of 70% isopropyl alcohol or a 10% bleach solution to prevent spreading pathogens.
Pruning requirements vary significantly by growth habit. Indeterminate (vining) tomato varieties require regular, ongoing sucker removal, while determinate (bush) varieties typically require little to no pruning, as removing their suckers can drastically reduce the final yield.
Starting New Plants from Suckers
Suckers removed from the tomato plant can be used for vegetative propagation, creating a genetic clone of the parent plant. The process is simple because tomato stems readily produce adventitious roots. A healthy, four to eight-inch sucker is the ideal size for this cloning process. The lower leaves should be stripped from the cutting, leaving only a few leaves at the top, and the stem can then be placed in a glass of water or planted directly into moist potting soil. This technique quickly generates additional plants without the six to eight-week wait required for seedlings.