How to Prune Tomatoes

Tomatoes were originally domesticated by the ancient Aztecs from a wild species native to Central and South America. The Aztec word for tomato is “xitomatl,” which means “plump fruit with a navel.”

Today, over 25,000 varieties of tomato are grown throughout the world. And growers are constantly fine-tuning the best ways to grow these plump fruits.

Pruning tomatoes is one technique that can help you get the most out of your crop. These are some tips and techniques to get started.

Do tomatoes actually need pruning?

Tomatoes will grow and produce fruit without pruning, but the plants often become overgrown and difficult to manage if left unpruned.

The extra time you put into pruning your tomatoes often promotes better fruit and healthier plants. These are some of the key benefits of training your plants.

Maximizes photosynthesis. Leaves need to receive light in order to make sugars for growth and fruit set. The leaves on a well-pruned tomato plant will have ample space to get lots of sun, which leads to more sugar production and a stronger plant. Whereas, an overgrown tomato plant can waste a lot of its energy producing leaves that will only be shaded out by other leaves.

Encourages earlier and larger fruit. Pruned and staked plants typically produce bigger fruit, two to three weeks earlier than unpruned plants. It’s believed this is because restricting vegetative growth allows the plants to put more of their energy into fruit production.

Better tasting tomatoes. All those plant sugars being channeled into the fruit often means better flavor as well.

Reduces disease risk. Good air flow between the leaves and fruit will prevent fungal problems and discourage insect pests. Also, if you stake your tomatoes, this will keep them off the ground and prevent soil-borne diseases.

More efficient use of space. You can fit more plants into a smaller area when they’re pruned and compact.

Determinate vs. Indeterminate Tomato Varieties

Your tomato’s variety influences how you prune your plants. Tomatoes are classified into what are known as determinate and indeterminate varieties.

Determinate tomatoes have a predetermined number of stems, leaves and flowers that the plant will produce. Because of this, they naturally have a compact growth habit and need minimal pruning.

Indeterminate tomatoes will continue to produce leaves, stems and fruit until frost. These varieties need considerably more pruning to keep them in check.

Your seed package or plant tag will tell you if a tomato variety is determinate or indeterminate.

nipping tomato shoot

Pruning Techniques

1. Simple Pruning

As a tomato plant grows, it will send out side branches at the crotches where the leaves meet the main stem. It’s best to remove these side shoots as soon as possible when they’re soft and pliable. Simply grasp the shoot between your thumb and forefinger and either pinch it or bend it back and forth until it snaps off.

If your shoot has gotten too old and tough to easily snap, you’ll need to use a clean pair of pruners to cut it off.

2. Missouri Pruning

Instead of removing an entire side shoot like with simple pruning, Missouri pruning only removes the tips of side shoots, leaving a few leaves behind. This can provide more leaves for photosynthesis. A disadvantage is that these tipped shoots will produce even more side shoots to prune later.

3. Root Pruning

Cutting some of a tomato’s roots will stress the plant, which can trigger it to mature more quickly. Some gardeners use it as a way to strengthen tomato plants. When your first few tomatoes are starting to ripen, insert a shovel or a long kitchen knife a few inches from the base of the plant. Insert it to a depth of about 8-10 inches (20 to 25 centimeters) and only cut halfway around the plant.

4. Topping

Tomatoes only have a short time to ripen their final fruit at the end of the growing season. You can encourage these last tomatoes to fully ripen by cutting the tops off your plants about a month before your last frost. You need to remove the terminal tips of the main stem or stems. This will stop any further growth and cause the plants to put all their efforts into ripening their remaining fruit.

Should you prune to one main stem or many?

The easiest approach is to train your plant to one main, central stem and pinch off any side shoots as it grows. Another option is to allow 2 to 4 side shoots to grow and form side branches, but any more than that often becomes unmanageable. This will take more space and require a stronger support structure.

To ensure a strong main stem, always prune off any side shoots below the first cluster of flowers. Make sure any side branches you start to train are the next shoots directly above the first flowers.

How to Tie the Stem

Both determinate and indeterminate tomatoes will need to be tied to a support structure. A single stake is probably the most common, but there are other types of support structures you can use.

A good time to start tying your young tomato plant onto its support is when the first blossoms appear. But you can start tying it up before then if it’s obviously leaning over and needs support.

Use soft materials for ties, such as pantyhose, old shirts or sheets cut into strips, thick twine or string or Velcro strips. These won’t damage the stems.

Start by wrapping your tie around the stem and underneath a leaf. The leaf will keep the tie from riding up. Then, cross the tie over itself and wrap the other end around your support structure and tie a knot to secure it. This will create a figure 8 in the tie, which provides a cushion between your structure and the stem. Allow an inch or two of slack in your tie so that the stem is not directly against the support.

Related
Do You Have to Stake or Cage Tomatoes?
5 Mistakes to Avoid When Growing Tomatoes
Edible Landscaping: A Delicious Way to Garden

 

57 comments

Margie FOURIE
Margie FOURIE2 months ago

I try at times.

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Carl R
Carl R3 months ago

Thanks!!!

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Leanne K
Leanne K3 months ago

Really? I let mine do what they liked. Massive ground cover, tomatoes for the birds. Me? Didnt get to eat one but was amazed all the same.

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One Heart i
One Heart inc3 months ago

Thanks!!!

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Leo C
Leo Custer3 months ago

Thank you for posting!

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Janis K
Janis K3 months ago

Thanks for sharing

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One Heart i
One Heart inc3 months ago

Thanks!!!

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Leo C
Leo Custer3 months ago

thank you for sharing!

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heather g
heather g3 months ago

Thanks - I need to do some thinning out to give them more sun.

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Naomi Dreyer
Naomi Dreyer3 months ago

Excellent article. Thanks.

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