What exactly are the suckers on tomato plants? I was told that if you pinch them off, your plant will concentrate on growing the fruit, instead of producing the suckers. When should I pinch them off? How do I determine which ones they are?
Pruning directs a tomato plant’s energy from producing foliage to the production of fruit. Pruning involves removing the lateral branches—also known as suckers. Suckers arise at the junction of the leaf and the stem.
Some of the advantages of pruning are larger fruit, earlier-maturing fruit, the ability to have closer plant spacing, easier pest control, and easier harvest. The disadvantages of pruning can include fewer fruits per plant and increased labor.
The primary factor in determining how severely to prune a plant is the plant type—indeterminate or determinate. An indeterminate plant keeps growing and producing fruit until it’s killed by frost or disease. When the branches of a determinate plant reach a certain length or age, they stop growing and producing fruit.
The indeterminate varieties are generally pruned down to one or two main stems. In the single-stem system, all of the lateral branches, or suckers, are removed. In the double-stem system, all but one of the suckers are removed. The sucker immediately below the first fruit cluster is allowed to grow and produce a second stem, which will also produce fruit. All suckers on the second stem are removed.
The suckers on determinate plants are normally removed as they would be in the double-stem system with indeterminate types. The sucker immediately below the first fruit cluster is left intact. Depending on the natural vigor of the variety, two or three suckers below this fruit cluster may be left intact.
If you are going to prune, wait until the suckers are large enough to handle easily (1 to 2 inches long). Simply pinch or snap off the suckers. Keep an eye on the lower branches of a tomato plant for further pruning. The lowest branches are prone to be the first infected by fungi or disease, as water splashed from the ground may carry spores to the lowest branches. When the branches and/or the leaves show signs of spotting or yellowing, the entire branch should be pruned and the material disposed of. Do not compost this material as the compost pile may not get hot enough to sterilize it.