Pruning Tomato Plants
For many of us, the thought of cutting off parts of a healthy plant is hard. Why would you want to do that? The answer is explained in this article about pruning tomato plants. Hint – pruning can protect your tomato plant from disease and produce more fruit – who doesn’t want more tomatoes? So, read on to learn more about why and how to prune your tomatoes for a successful crop.
Linda Stein, Dakota County Master Gardener
One of the hardest things I do in the garden - emotionally, not physically - is pruning. The thought of cutting off healthy parts of a plant seems somehow wrong. But, in fact, it is one of the steps you can take to promote greater vegetable production in many varieties of plants, particularly tomatoes.
Pruning is the process of selectively removing parts of a plant to promote healthy plant growth. Pruning can help increase fruit size and overall production. It can also help reduce the occurrence of diseases in the plant.
A primary focus of pruning in tomatoes is on suckers. Suckers are the growth that appears at the intersection of two branches. These suckers compete with the primary stem causing an overabundance of vegetative growth and resulting in reduced flowering, fruit set, and yield. If you are hesitant to cut that healthy looking stem and leaf, remind yourself that you are growing the plant for the fruit it will produce, not for the foliage.
Another reason to remove the suckers is that the removal of excess growth will promote air circulation in the plant allowing the plant to dry out more quickly after a rain or after watering. In addition, when I first plant my tomatoes, I prune some of the lower branches to reduces the risk of soil splatter that can bring diseases to the plant.
However, in general the best time to do major pruning depends on the type of tomato plant you are growing – determinate or indeterminate. Determinate tomatoes are those that grow to a predetermined height and produce all their fruit within a few weeks. These plants should be pruned when they get to be about 1 - 2 feet tall. Only prune those suckers that appear below the first fruit cluster. Research has shown that it doesn’t help to remove suckers above. Indeterminate tomatoes are those that continue to grow and produce over the course of the growing season. These plants should be pruned frequently along the full length of the plant.
As soon as either of these plant types set fruit, it is suggested that you thin lower foliage and suckers to improve airflow and reduce the severity of leaf spot diseases. Prune by pinching off the growth you wish to remove. If the piece is too thick to pinch, cut with a clean shear. In all cases, do not prune more than 1/3 of the plant.
Proper pruning as part of your gardening routine should help promote healthy plants with maximum yield. Here’s to a bumper crop of fresh tomatoes.
References:
How to Prune Tomatoes , Iowa State University, (YouTube)
Pruning Greenhouse Tomatoes for Optimum Yield, https://e-gro.org/pdf/E208.pdf
How to Properly Prune Your Tomatoes, LSU College of Agriculture, http://www.lsuagcenter.com/topics/lawn_garden/home_gardening/vegetables/home_garden_crops/pruningtomatoes
Pruning Tomato Plants, UNH Cooperative Extension, https://extension.unh.edu/resources/files/Resource000598_Rep620.pdf