How to successfully prune tomato plants

Were you successful in raising up your tomato seedlings? Did you go to the trouble of hardened them off and planting them out in the garden? Are they now putting on a ton of growth? Are you are watching your young plants grow and thinking when is the best time to start pruning my plants?

If you’ve found yourself asking these questions, don’t fret gardening friends! In today’s growing guide, we break down the ins and outs of pruning tomatoes. We are here to give you with the knowledge you need to be successful when it is time to prune your tomato plants. So grab your pruners and let’s dive in!

What’s the difference between indeterminate and determinate tomato varieties?

Indeterminate tomato plants

The first step to know when to prune your tomato plant is to do some research. First, you need to know the varieties that you are growing. Tomatoes fall under two broad categories, being indeterminate and determinate. The difference between the two is that indeterminate tomatoes will put on growth throughout the growing season. That means they will continue to bear fruit until the plants become spent or die back from frost damage. Common types of tomatoes that fall into this category include:

• many of the vining-type tomatoes 
• For example: cherry, grape, slicer, and beefsteak.

But remember, there are always exceptions!

Indeterminate tomatoes will need to be trellised, caged, or staked. This will help to support their growth since some vines can reach up to 6-7 feet in length. Pruning can help maximize production and reduce disease pressure. This is because you increase the air flow and reducing branches that suck energy from the main stem.

Determinate tomato plants

By contrast, determinate tomatoes grow to a specific size and then set their fruit all at once. Once the fruit is set, these plants will halt their growing process. Determinate varieties of tomatoes usually only bear one harvest of fruit. Indeterminates are capable of producing many harvests throughout the season. Tomatoes that fall into the determinate tomato category of tomatoes are:

• paste tomatoes and bush-like tomatoes

Which varieties of tomatoes need pruning?

When it comes to pruning tomatoes, only hard prune your indeterminate tomato varieties. Doing so will improve production and create much needed airflow to curb fungal and bacterial diseases. Determinate varieties set their fruit all at once. Pruning them will actually interfere with fruit production. To prevent disease, you can trim back branches that are touching the ground on determinate varieties. But only do what is necessary so as not to interrupt the growing cycle.

Why is it important to prune indeterminate tomatoes?

Indeterminate tomatoes can branch out quite a bit once they start to put on growth. Pruning them back throughout the season will be a necessary task for most home gardeners. Not all gardeners choose to prune their tomatoes. We have found that pruning back our tomatoes helps us to better control diseases and results in higher yields.

It’s all about energy and fruit production

By pruning your indeterminate tomatoes, more energy can put into producing fruit. You will still need some foliage to support fruit production. It also provides protection to the fruit. But too much extra foliage and the plant will put most of its energy into only producing stems and leaves. This comes at the expense of producing fruit.

Pruning also provides extra airflow throughout the plant. Airflow is important when it comes to tomatoes. Pruning helps to reduce humidity around the plant which can lead to the growth of fungal and bacterial diseases. Start by pruning the bottom leaves of your tomato plants where they touch the soil because this is also an important task. This can help to curb disease pressure from taking hold of your plants.

When is the best time to prune tomato plants?

Timing is important when it comes to pruning your tomato plants. It is depends upon on your growing zone, local climate, and how far along your plants are in their growth cycle. A good rule of thumb is to wait until your plant has started to flower and branch out, usually sometime in June or July. You may want to prune them again two to three times depending on their growth habits. 

Think about the growing season

Also, it is important to think about and the duration of your growing season when pruning your plants. We like to prune every couple of weeks and watch the growth of our tomato plants. You want to stop pruning your tomatoes shortly before your first harvest. This way the plant can provide a bit of protection with its leaves to prevent sun scalding on the fruit.

How to prune tomato plants

When it comes to pruning tomatoes, you may have heard the term ‘suckers’ before. Suckers are the branches that are at the juncture point between the main stem and the true leaves. We call them suckers because they ‘suck’ energy away from the plant. This energy is better served for fruit production rather than creating more branches. When you begin the pruning process, you want to first identify the main stem of your tomato plant. This is the strong inner core of your plant. You will then begin pruning out any suckers that have formed. Leave only the suckers below the lowest fruit or set of flower clusters on your plant. These suckers are the strongest ones on the plant. They will help to support growth and will form a second stem to bear fruit.

The importance of early season pruning

When it is early in the season, the suckers will be small. You can remove them before they grow out into a developed branch. Sometimes these suckers can also form at the bottom of the plant. You will see them develop where the roots make contact with the soil. Remove these suckers so that energy can go back into the plant to support fruit production. You can remove the suckers by hand using scissors or hand pruners. We like to use sharp hand pruners for better accuracy, but scissors will work as well. Tomatoes can be prone to certain fungal and bacterial diseases. Between pruning sessions you want to disinfect your cutting tools. Doing so will help to prevent the spread of diseases from one plant to the next from your cutting tools.

Final thoughts

Do you have tomatoes on your list of plants to start in your garden this year? If so, pruning them will be an important task for you as your plants start to put on growth. We hope the information in today’s guide will give you with the knowledge that you need to get started. If you find yourself stuck and in need of advice when it comes to pruning your tomato plants this season send us a message. Always feel free to reach out to us by email or on our socials or leave a comment on our article. We always love to hear from you all! Until next time gardening friends, do not be afraid when it comes to pruning your tomatoes. They really are resilient little plants and will forgive you if you accidently trim a little too much!