6 Simple Pruning Tips for Increasing Your Tomato Harvest

Make way for a bumper crop of fruit with a little tomato plant pruning.

Tomato plants have a natural tendency to produces lots of leaves and relatively fewer fruits. However, it's easy to balance leaf and fruit production by doing a little tomato plant pruning. Not only will trimming off excess foliage lead to more tomatoes per plant, but the fruit that is produced will be larger and higher quality. It only takes a few minutes per plant to prune away unneeded growth. By reducing the overabundance of leaves, your tomato plants can focus more energy on growing colorful, flavor-rich fruit. Use these 6 simple tips to guide your tomato plant pruning efforts.

person pruning tomato plant
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1. Prune all your tomato plants.

Tomatoes are grouped by growth habit. A tomato variety is classified as either determinate or indeterminate. Determinate tomatoes grow to about 4 or 5 feet tall, stop growing, and begin producing fruit. All fruit on a determinate tomato plant ripens within about 4 to 6 weeks. Indeterminate tomatoes, on the other hand, don't stop growing at a defined height. They continue to put on new foliage, flowers, and fruit for months, until they're killed by frost.

By nature, indeterminate tomato plants produce more foliage than determinate tomato plants. For this reason, indeterminate tomatoes benefit most from pruning to remove excess foliage, but pruning boosts the production of determinate tomatoes too. The pruning time for determinate tomatoes is simply shorter than indeterminate varieties that produce new leaves and fruit for several months.

If you're not sure if the tomato varieties you're growing are determinate or indeterminate, a quick Internet search of the name should clarify things. Common indeterminate varieties that especially benefit from pruning include 'Sungold,' 'Sweet 100,' 'Juliet,' 'Big Boy,' 'Early Girl,' 'Big Beef,' 'Jet Star,' 'Brandywine,' and 'Cherokee Purple.'

2. Start pruning after flowers appear.

Tomato plants begin to produce suckers, or extra stems with foliage you don't need, after the first flower buds appear and open. This generally happens a couple of months after placing young transplants in the garden. Tomato plants typically begin flowering in June or July.

Prune plants in the morning, after any dew or overnight rain has dried off the foliage. This will help avoid spreading plant diseases. Aim to prune plants when the suckers are between 2 and 4 inches long. Determinate tomato plants (those that reach 4 feet tall or so and stop growing) only need to be pruned once. Indeterminate tomatoes can be pruned every couple of weeks as they continue to produce new leaves.

3. Remove suckers.

In general, tomato plants produce main stems and main leaf branches. Fruit develops on the main leaf branches. Suckers grow in the intersection between the main stem and main leaf branches. They're easy to spot once you know what you're looking for.

Remove suckers by pinching them off with your thumb and forefinger or use a pair of clean, sharp pruners. Aim to remove most suckers you see. Both an art and a science, tomato plant pruning is specific to the variety and the growing conditions in your garden. When in doubt, leave a sucker and watch the outcome over the course of the season. Then next year, make modifications to your technique based on your observations.

4. Remove lower leaves.

Prune plants to remove leaves on the lower 6 to 12 inches of the main stem. Removing these leaves helps prevent disease-causing bacteria and fungi in the soil from getting splashed up onto the plant whenever it rains or you water.

5. Thin out fruit on slicing tomatoes.

Tomato varieties that produce slicing fruit, such as 'Celebrity,' 'Jet Star,' and 'Brandywine,' will produce larger fruit if the plant's fruit clusters are reduced to one or two tomatoes. Simply snip out developing fruit, leaving the largest one or two tomatoes in the cluster. This type of fruit pruning is called thinning. If bigger tomatoes are your goal, thin the fruit so your plant will direct its energy into the remaining fruit.

6. Keep it clean.

Pruning creates open wounds on tomato plants. And just like when you get a cut, wounds are entry points for infections. Wash your hands with soap and water or use a hand sanitizer frequently when pruning tomatoes. If you're using pruners, keep them clean too by wiping them with a diluted bleach solution or rubbing alcohol between plants.

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