How to Prune Tomatoes for High Yields and Why You Should Always Do It

I admit it. I’m obsessed with tomatoes. Every spring I plan my tomato harvest and plant every variety I can get my hands on. I visualize my bounty and always imagine huge yields filling my baskets to the brim. Then one year the inevitable happened.

I got busy and ended up leaving the tomatoes to their own fate. My harvest was less than impressive.

Then I discovered the technique of pruning tomatoes to increase my yields. If you prune tomatoes at the right time in the right way, you get a bigger harvest than you ever imagined.

Whether you’re a tomato lover, an avid grower, or a beginner, let’s look at pruning tomatoes for high yields.

Why You Should Prune Tomato Plants

Pruning tomato plants isn’t just for higher yields, but it sure does help. There are a couple of other reasons which we should cover before we get on to the actual process of pruning tomatoes. When you prune for big harvests, you benefit the tomato plant in other ways.

1. Prolongs Harvest

When you prune your tomato plant, it reduces the amount of energy the plant puts into foliage, and directs that growth to the fruit. This means more fruit over a longer period of time.

2. Prevents Disease

With less foliage, airflow passes through the plant easier. This helps to prevent many tomato diseases. Pruning also helps maintain plant health, which in turn assists the plant in resisting disease and putting all its energy into fruit growth.

3. Larger Fruit

That’s right, not only do you get bigger harvests, you get bigger fruit. With more energy available for fruiting over a longer period of time, your individual fruits should be bigger than if you don’t prune.

4. Stops Excessive Growth of Foliage

When a tomato plant is young and before fruiting, it can double in size every 15 days or less. Once the plant sets fruits and starts to weigh them down, the whole plant will lay on the ground if not staked properly.

Once a tomato plant reaches 18 inches tall and hasn’t been pruned, there is the risk of it falling, breaking, or having health issues.

An indeterminate tomato plant can cover a huge area if left to its own devices. By then it will likely be diseased with a poor harvest.

5. Earlier Ripening

Pruning your tomato plant means the plant concentrates on the fruit harvest sooner because there is less foliage using up valuable nutrients, energy, and sugars.

How to Prune a Tomato Plant for High Yields

There are different pruning techniques when it comes to tomato plants. Over time, you’ll figure out what method you prefer and how it affects your harvest and overall plant health.

Remove The Suckers for High Yields

Sometimes called side shoots or laterals, the suckers grow in the axis of the stem and branches. If you leave them, the suckers grow just like the stem of the tomato plant and grow their own flowers and fruit.

Often though, they don’t serve any purpose other than growing bigger and taking vital energy from the rest of the plant.

• Remove suckers when they are half an inch or less in length. At this size, you can pinch them off with a finger on one side and a fingernail on the other. Pinch and pull for a clean cut.
• If they are bigger than half an inch to about four inches, snap them off, but make sure they are completely broken off the plant before pulling away. It’s easy to take a strip off the stem because you didn’t detach the sucker fully.
• Cutting with a garden knife or similar is not recommended with suckers because the fine cut can take a while to heal and disease can set in. However, when they get big and thick, it is the best way. Make sure it’s a clean cut close to the stem. Leaving a stump will make the wound site rot and likely cause disease.
• When the tomato is at its peak growing phase, check for and remove suckers at least once a week.

There are two schools of thought when it comes to how you remove suckers. One way is to remove the top half of the sucker, leaving the bottom half. The theory behind this idea is you leave some leaves of the sucker on to assist with photosynthesis and to prevent sun scold of the fruit and plant.

The other method is you remove the whole sucker to prevent it from taking vital nutrients from the main plant and fruit. Removing the sucker in its entirety also helps airflow and sunlight into the plant.

Pinch the Main Stem for High Yields

Like many vegetables and other plants, tomatoes benefit from pinching out the center leaves of the main growing stem.

You do this to encourage the plant to be thicker and more compact, rather than growing taller and thinner. Tomato plants with the center pinched out, grow bigger fruit because they are putting energy into fruit growth, not spreading the vine out.

It’s also much easier to stake or tie a pinched plant that is compact.

Find the vertical center stem and cut it off to the size you want the plant to be. A good rule of thumb is if the plant is in a tomato cage or held with a tall stake, cut the plant back once it reaches the same height as the support.

Many tomato plants are so vigorous that you will need to cut or pinch out the main growing stem regularly throughout the season.

Thin Tomato Plants for High Yields

Another pruning method for tomato plants for a higher yield is to thin out or remove some of the branches. We’ve already looked at removing the suckers or laterals and pinching out the main growing stem. Both those methods reserve energy for growing more fruit and bigger fruit.

Thinning achieves the same goal by removing some of the excessive branches and leaves.

Tomato plants will often become very bushy when you remove laterals and pinch out the main growing stem. This means more energy is diverted from quality fruit production to maintaining the branches and leaves.

Simply remove the branches that have no flowers or fruit on them. Just keep enough for a healthy plant and you will see an increase in the size and number of your fruit.

While you’re doing this, make sure to remove the lower branches and leaves, especially those that are touching the soil as this is how many soil-borne diseases get onto tomato plants.

When to Prune Tomato Plants for High Yields

Timing is key when it comes to pruning tomatoes.

Early to the Middle of the Season

• Remove the suckers or laterals early on and throughout the peak of the growing phase.
• Prune off or remove flowers until the tomato plant is at least 18 inches tall.
• Remove any flowers that have developed before you transplant the tomato plant into the garden. This allows the plant to concentrate on getting strong and healthy (for bigger yields) rather than producing fruit too early in the season.

Mid to Late Season

• Pinch the main center stem to stop the growth and height. This ensures all the remaining energy and sugars in the plant are directed to fruit production and growth.
• Keep pruning away any excess growth including laterals. Remember to prune as close to the main stem as possible without cutting it. This prevents any stumps from rotting and getting infected.

Not all Tomato Plants Need Pruning

Only indeterminate tomatoes need to be pruned to create a higher yield. In fact, pruning a determinate tomato plant can often create a smaller harvest. What’s the difference between indeterminate and determinate?

Determinate tomatoes grow to a certain height and set their fruit and mature it at the same time.

Indeterminate is vining and continues to grow and set fruit all season. This is why pruning works on indeterminate. You are using all that growth energy to be concentrated on fruit setting and maturing for both volume and size.

3 Top Tips for Pruning Tomato Plants For High Yields

1. Don’t prune tomato plants when the foliage is wet. This can create an environment for disease and bacteria to enter the cuts. Prune on a dry day and when the plant has had plenty of warm sunshine,
2. Remove the suckers or laterals when they are as small as possible. Keep doing this weekly (or more often if you have the time) throughout the season. You can’t do it once or twice because the tomato plant will just keep producing them, and this will affect both yield and fruit size.
3. Pinch off the main stem when the plant is the same height as the cage, stake, or at the height you desire. You can wait until late in the season, but if you don’t, just make sure to keep checking for more growth to pinch off. Also, make sure to pinch off the main growing stem at least 30 days before the first frost so all of the remaining energy of the plant is directed to the fruit to mature and grow in size.