How to Prune a Tomato Plant

Pruning for Better Fruit and Healthier Plants

Project Overview
  • Working Time: 15 - 30 mins
  • Total Time: 15 - 30 mins
  • Skill Level: Beginner
  • Estimated Cost: $0

Many gardeners prune tomato plants to improve the quality of the fruit, encourage better fruit production, speed up the ripening process, keep the plants from growing too large, and even manipulate the size of the plant's ripe fruit. However, plenty of gardeners do not prune tomato plants since it is not required, so you can experiment to see what works best for you.

How to Prune Tomato Plants

The Spruce / Adriana Sanchez

Read on to find out how to prune a tomato plant for a better harvest.

Why You Should Prune Tomato Plants

Pruning tomato plants helps direct the plant's energy towards producing fruit rather than producing more foliage. Removing suckers and yellowed leaves also encourages larger fruit, better airflow, fewer diseases, and for container-grown tomatoes, better size. Here's why.

Larger Fruit

Unpruned foliage eventually grows into new branches that form fruit but experienced growers advise pruning to produce larger fruit earlier in the season.

Better Airflow

When a tomato plant is pruned properly, all of the foliage receives adequate sunlight, and the plant can photosynthesize more efficiently, boosting growth and fruit production. When leaves are forced into shade, such as when bushy plants are on the ground, the amount of sugar they produce is reduced and growth is impeded. 

Fewer Diseases

If you have fungal issues in your garden, pruning can solve the problem of tomato plants lying on the ground or leaves coming into contact with the soil. Pruning the plants may discourage the development of soil-borne fungal diseases in the plant.

Tip

Instead of pruning, staking or caging your tomato plant will also keep the plants and leaves off the ground. Choose a cage that's large enough to support the majority of your plant's length.

Controlling Size

Pruning is a good way to control the size of tomato plants growing in containers. Otherwise, a vigorous tomato vine can outgrow its pot. Ideally, choose compact tomato varieties for planting in containers to minimize pruning.

Pruning Indeterminate vs. Determinate Tomatoes

Not all types of tomatoes need to be pruned. Learning whether you have determinate or indeterminate tomatoes can help you decide.

Determinate Tomatoes

Determinate tomatoes do not need pruning. Determinate tomatoes, often called bush tomatoes, are those varieties that grow to a fixed mature size, usually around 4 to 5 feet. These tomatoes typically ripen all of their fruit within a few weeks so pruning doesn't provide much benefit.

Indeterminate Tomatoes

If you're growing indeterminate tomatoes, which produce fruit regularly over the course of a season, pruning is encouraged. Indeterminate tomatoes continue to grow throughout the season, eventually becoming very large vines that could reach up to 20 feet in length. Pruning controls the vine's size and encourages larger tomatoes instead of more foliage and smaller tomatoes. Many of the most popular tomato varieties, including cherry tomatoes, heirloom tomatoes, and cultivars such as 'Big Boy,' 'Beefsteak,' and 'Brandywine', are indeterminate.

When to Prune Tomato Plants

There are early-season ripening, mid-season ripening, and late-season ripening tomatoes. Regardless of which type of tomato you have, the time to prune tomato plants is when you first see that the flowers are opening. The timing may be around June or July. Continue pruning once or twice more every two weeks until harvest time.

It's also best to prune in the early morning on a dry day so wounds can easily heal.

What You'll Need

Equipment / Tools

  • Small pruning shears
  • Stakes and twine (as needed)

Materials

  • Household disinfectant

Instructions

How to Prune Tomato Plants

  1. Locate the Suckers

    Look for the tomato suckers, which grow in the "V" space between the main stem and the branches on your tomato plant. If left unpruned, these suckers will eventually grow into full-sized branches, adding lots of foliage and, eventually, a few fruits. This will also result in a tomato plant that quickly outgrows its space in the garden.

    closeup of tomato suckers

    The Spruce / Michele Lee 

  2. Remove the Suckers

    • Suckers under 2 inches long can simply be pinched off with your fingers.
    • For larger suckers, use a pair of clean pruners, disinfecting them as you move from plant to plant to protect against spreading diseases.
    • Clip carefully to avoid tearing or nicking the tomato vine or nearby leaves. Make sure the cut is clean, without ragged edges or splits in the vine.
    • Whenever possible, remove the suckers when they are small. Removing large amounts of foliage at one time can stress the plant.
    closeup of someone pinching off a tomato sucker

    The Spruce / Michele Lee 

  3. Remove or Stake Long Branches

    Branches that are low-hanging and touching the ground should either be staked up or removed. Leaves touching the ground can be susceptible to bacteria, fungi, and viral infections that can spread through the rest of the plant.

    a piece of fabric used to stake tomatoes

    The Spruce / Autumn Wood

Common Tomato Pruning Mistakes to Avoid

Pruning tomato plants correctly helps promote vigorous growth and more fruit production. Here are some mistakes to avoid.

Pruning Wet Plants

If your tomatoes are wet from rain or sprinklers, wait until the foliage is dry before pruning. Clipping, pruning, or deadheading wet plants, fruit, or flowers encourages the spread of harmful bacteria or fungi.

Removing Too Many Leaves

Never prune away more than a third of the plant's foliage, especially during a hot, dry summer. Harsh, intense sunlight and heat may scald tomatoes. Prune around the plant but keep leaves that lightly shade the growing fruit.

Pruning With Dirty Tools

Clean your pruning shears after each use to avoid spreading bacteria and fungi between plants. Wipe your pruning scissors or shears with 70 percent isopropyl alcohol before pruning the next plant.

Not Removing Lower Leaves

In addition to suckers, remove the lowest leaves on your tomato plants. Lower, older leaves may have picked up fungal spores from the ground so removal is important. Also, remove any yellowing or unhealthy leaves from any location on the plant when pruning.

Letting Suckers Grow Before Pruning

Leaving suckers on the plant for too long can cause problems. The tomato plant wastes energy growing suckers, they can become heavy and weigh down the plant, reduce airflow, and turn into established offshoots that sap energy. For offshoots, use a method called Missouri pruning, which means you pinch off the offshoot right above the second set of leaves to keep the plant from going into shock.

The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Tomato Pruning. University of Wisconsin-Madison Extension.

  2. Pruning Tomato Plants. University of New Hampshire Extension.

  3. Pruning, Training, and Supporting Tomatoes. The Connecticut Agricultural Experiment Station.