All tomatoes are classified as either determinate or indeterminate

June 2, 2021

A sucker can be a lollipop, a bottom-dwelling fish, or even a human. A person who is easily deceived has been called a sucker since at least 1836.

If there is a sucker born every day, then your tomatoes are probably to blame. In the garden, a sucker is simply a new shoot or stem that, if left to grow, will compete with the main plant for food and water. 

Tomato suckers usually grow out of the spot where the stem and a branch of a tomato plant meet, a place called the axil. If you let suckers grow, they become another main stem much like an additional trunk on a tree. The new stem or sucker will go on to bloom, set fruit and yes, grow even more suckers.

All tomatoes are classified as either determinate or indeterminate, depending on their growth habit. Determinate tomato plants stop growing once they reach a few feet tall. 

Some of the more popular determinate tomatoes are so-called paste tomatoes, such as San Marzano and Early Roma. Oregon Spring is a round, early tomato that is even tolerant to some cold. The six- to seven-ounce Oregon Spring will be among the earliest tomatoes to ripen, and is ideal for cool northern or high-elevation gardens. Oregon Spring is also very resistant to verticillium wilt.

Determinate varieties of tomatoes do not need any pruning at all. They usually set their fruit after all branches are fully grown. They grow and ripen all at once. Once they set fruit they are done for the season. Since no new fruit will grow after pruning, you do not want to prune determinate tomatoes.

It is the indeterminate tomatoes that will need pruning. Most of the big, sprawling plants are indeterminate tomatoes. Everything from Big Boy hybrids to heirlooms such as Brandywine or Cherokee Purple are all indeterminate tomatoes.

These plants can get huge because they never stop growing. They also keep flowering and setting tomatoes right up until killed by frost.

When planting any tomatoes, remove the lower leaves and bury the stem several inches deep in the soil. Roots will grow from the buried stem, making your tomato plants stronger and more stable.

It is often advised to cut out or prune tomato suckers because the sucker growth can cut down on air movement and sunshine for the rest of the plant. This lack of circulation often leads to disease.

The tradeoff is that you might get more fruit if you let the suckers grow, although the tomatoes will often be smaller.

Staking tomatoes is hard enough, and if you add several new stems from suckers, your plant might be too big to lift off the ground.

It is probably best to cut out suckers for more manageable plants as well as healthier plants.

By opening up the plant to air and sunlight, the tomato leaves dry quicker after rain, so they are less susceptible to diseases that grow where moisture lingers.

A well-trimmed tomato plant makes it easier to find pests that can hide among abundant foliage. Best of all, pruning makes your tomatoes ripen faster.

Bear in mind that if you prune all of the suckers, your tomato plant will be more compact, and you will get fewer tomatoes. The tomatoes you do harvest will, however, be much bigger.

Always clean your pruners with an alcohol wipe before using and when going from one plant to another so you do not spread diseases. If your main stem is strong and healthy, you can safely leave a few suckers on each plant.

Prune the suckers from your tomato plants and you will get more vigorous growth, larger tomatoes and fewer diseases. And remember, it isn't just at the lollipop factory that a sucker is born every minute.

  • Paul Barbano writes about gardening from his home in Rehoboth Beach. Contact him by writing to P. O. Box 213, Lewes, DE 19958.

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