Pruning involves the selective removal of parts of a young tomato plant to redirect its energy. This practice shifts focus from producing excessive foliage to developing larger, higher-quality fruit. Pruning also improves air circulation within the plant’s canopy, which helps prevent fungal and bacterial diseases. Managing growth early creates a healthier, more productive plant structure that is easier to manage and harvest.
Identifying the Right Time and Target Areas
A tomato plant is considered ready for its first pruning when it has established itself and reached a height of about 12 to 18 inches. This stage often coincides with the appearance of the first flower clusters, making it a good visual cue to begin the process. Starting early is beneficial because it prevents the plant from wasting energy on side shoots that will eventually be removed.
The primary target for removal is the “sucker,” a small shoot that emerges from the axil, or crotch, between the main stem and a leaf branch. If left to grow, a sucker develops into a secondary stem that competes for nutrients and sunlight. Also remove any lower leaves touching the soil, as this foliage provides a pathway for soil-borne diseases to splash onto the plant.
Suckers appear as tiny, new growths at a roughly 45-degree angle from the main stem, distinct from true leaf branches. Removing these growths focuses the plant’s resources toward the primary stem. Regular inspection every seven to ten days is helpful for catching suckers while they are still very small.
Essential Techniques for Removing Suckers
The physical act of removing a sucker should be done with care to minimize stress on the young plant. If the sucker is small—less than one or two inches long—it can often be removed simply by “pinching” it off with your thumb and forefinger. This method is quick and creates a tiny wound that heals rapidly.
For suckers thicker than a pencil, use clean, sharp pruning shears or snips. Cut the sucker off cleanly, close to the main stem, to prevent tearing the plant tissue and creating a larger wound. Sanitize cutting tools with rubbing alcohol or a bleach solution between plants to avoid spreading pathogens.
Pruning should ideally be done during a dry part of the day, preferably in the morning, which allows the wound to dry out quickly in the sun. A dry wound is less susceptible to infection from fungal spores and bacteria. Never prune when the foliage is wet, as this is the easiest way to spread disease throughout the garden.
How Pruning Differs by Tomato Type
The intensity of pruning depends entirely on the tomato’s growth habit, which is categorized as either determinate or indeterminate. Determinate varieties, often called “bush” types, grow to a fixed height and produce the majority of their fruit over a relatively short period. These plants are generally self-pruning and require minimal intervention.
For determinate tomatoes, you should only remove suckers that appear below the first flower cluster, along with any low-hanging or diseased foliage. Removing too many suckers from a determinate plant will significantly reduce your total harvest, as their fruit production occurs at the tips of these side shoots. The goal for these varieties is simply to improve air circulation at the base of the plant.
Indeterminate varieties, known as “vining” tomatoes, continue to grow and produce fruit until the first frost. These types benefit most from aggressive pruning to manage their height and sprawling nature. Gardeners remove most suckers to maintain a single or double main stem, which directs the plant’s energy into producing fewer, but larger, tomatoes with better fruit size and faster ripening.