Expert Tips on Pruning Tomato Plants in Australia

At the junction where the leaves meet the central stem, lateral branches will start to grow. These are the ones that you need to control.

It’s no secret that I love growing tomato plants in my garden during summer.

There’s nothing quite like harvesting fresh tomatoes whether you throw them in a salad, slice them up for sandwiches or make your own tomato sauce.

However, are you aware that certain types of tomato plants need to be pruned in order to get the best from them, while there are others that are best left unpruned?

Indeterminate vs determinate tomatoes

There are actually two different types of tomato plants, determinate and indeterminate.

You need to understand which type you’re growing so that you know how to prune them correctly.

Determinate tomatoes

Determinate tomatoes are also known as bush tomatoes. These will grow to a certain height (around 1.2 metres) and then usually stop growing upwards.

Once they’ve reached their optimum height, they start producing flowers and fruits.

One common type of determinate tomato is the Roma. I decided to grow these for the first time this year and they have a totally different growth habit to the indeterminate tomatoes that I’m used to growing.

roma tomato plant | Fruit & Vegetables

You’ll also find that with determinate tomatoes, your fruit will generally grow and ripen all at once. This makes them ideal if you want to make tomato sauce.

In some cases, you’ll only get one batch of fruit but I’ve noticed with the Romas I’m growing that a second batch is now forming.

These types of tomato plants generally don’t require pruning and it’s recommended that you don’t prune them because you might reduce their yield.

I haven’t pruned the ones I’m growing and have only tied them to the trellis at regular intervals to keep them upright.

Indeterminate tomatoes

Indeterminate tomatoes are also known as vine tomatoes.

They will continue to grow and also send out lateral branches and will produce fruit continuously throughout the season.

vine tomato plant 1 | Fruit & Vegetables

These are the ones that you need to prune to control their growth.

How indeterminate tomatoes grow

Indeterminate or vine tomatoes have a central leader on which large leaves will grow. This leader will just continue to grow right throughout the season.

At the junction where the leaves meet the central stem, lateral branches will start to grow. These are the ones that you need to control.

Tomato pruning 3 | Fruit & Vegetables

Otherwise, you’ll have tomato branches growing in every direction and taking over your entire garden.

If the laterals are left to grow, they will be hard to control as they grow out sideways, making them difficult to stake.

This can result in the branches laying on the ground and the fruit getting spoilt because it’s in contact with the soil.

When to prune indeterminate tomatoes

You need to start pruning your indeterminate tomatoes as soon as they’ve established themselves and start growing their lateral branches.

How to prune indeterminate tomatoes

Pruning out the lateral branches of your indeterminate tomatoes takes vigilance and dedication because they can grow very quickly.

Tomato pruning 6 1 | Fruit & Vegetables

Therefore, you really do need to inspect your tomatoes on a daily basis and remove these lateral branches as soon as you see them.

Lateral growths are easier to remove when they’re still small because you can just pinch them off with your fingers.

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To do this, you need to inspect your tomato plants on a constant basis, paying particular attention to where the leaves join the main stem.

As soon as you see some growth in this junction, just pinch it off.

Bear in mind, that sometimes you might miss a lateral in its early growth stage. If this happens, just use a pair of secateurs to snip it off close to the main stem.

Tomato pruning 2 | Fruit & Vegetables

One tip I’m going to share with you is that if the lateral is already forming into a branch, you can actually plant this in a different spot in the garden and it will produce roots and grow into a new plant.

In the event that you haven’t been quite vigilant enough and one or two laterals have escaped your scrutiny and are already growing into a nice branch that you don’t want to remove, don’t panic.

I have this happen quite often with the tomato plants I grow. All I do is insert another stake into the ground very carefully and tie the lateral to this so that it’s not hanging on the ground.

Tomato stake | Fruit & Vegetables

Tidying up your tomato plants during the growing season

Another thing I like to do with my tomato plants during the growing season is to tidy them up and limit the growth of the leader so that it doesn’t get out of control. 

Once the leading stem reaches the top of the stake or support system you have in place, you can stop it from growing any taller by just cutting off the tip or growing point. 

You should also remove any lower leaves that are touching the ground to keep the plant nice and clean.

I also like to remove any leaves that are starting to yellow off so that my plants put all of their energy into producing fruit.

Tomato Pruning FAQ

What happens if you don’t prune tomatoes?

If you don’t prune indeterminate tomato varieties, you’ll have a mass of growth with lots of lateral branches growing sideways and often laying on the ground.

Should tomato plants be topped off?

If you’re growing indeterminate tomatoes, you can top the central stem once it reaches the top of the stake or support. Determinate tomatoes should not be topped because you might get a second flush of fruit.

Can you prune tomatoes with scissors?

As long as your scissors are sharp and clean, you can use these to prune your tomatoes because the stems or laterals are fairly soft.

Photo of author

Annette Hird

Annette Hird is a gardening expert with many years of experience in a range of gardening related positions. She has an Associate Diploma of Applied Science in Horticulture and has worked in a variety of production nurseries, primarily as a propagator. She has also been responsible for a large homestead garden that included lawn care, fruit trees, roses and many other ornamental plants. More recently, Annette has concentrated on improving the garden landscape of the homes that she has lived in and focused a lot of energy on growing edible plants as well. She now enjoys sharing her experience and knowledge with others by writing articles about all facets of gardening and growing plants.


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