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Pinching Out Tomatoes: A Beginner’s Guide

By Emily Peagram
28th April 2015

Growing tomatoes is easy and fun, and with a little bit of pruning, they will produce lots of delicious red fruit for the summer. If you’re unsure about when and how to start pinching out tomatoes – or even what pinching out means – we’ve got all of the answers for you.

What does pinching out tomatoes mean?

Pinching out is an easy process of removing extra side shoots with your fingers, so the plant puts its energy into growing one single stem with fewer branches and larger fruits. You can also pinch out the top of the main stem (or growing tip) to stop the tomato plant growing too tall.

What happens if you don’t pinch out tomatoes?

If left untrained, tomatoes will produce a large number of flowers on a big mass of foliage, which puts pressure on energy reserves, results in poor quality pickings and is difficult to support. The pinching out method of pruning means you support one single stem with a cane or string, and it also staggers the production of buds throughout the season, creating in multiple, high-quality harvests – yum!

Where do you pinch a tomato plant?

You pinch out side shoots, which grow between the main vertical stem and the fruit trusses. “What is a truss?”, we hear your ask. Trusses grow out from the main stem, like branches, and are what will carry the fruit.

You can also pinch out the top of the main stem (the vertical trunk of the tomato) to prevent the tomato plant getting too tall.

When should you start pinching out tomatoes?

For side shoots, wait until the first flowers appear on a fruit truss. Keep pinching out regularly from that point, as it’s easier to remove young side shoots than chunkier, older ones. Simply check the plant every week or each time you water.

If you want to pinch the main stem, wait until you have at least four fruit trusses if you’re growing them outside or six inside. Or you can prune the plant when it’s reached the height you’d like it to be – at the top of your greenhouse or its supporting cane, for example. This job must be done gently to avoid any damage and towards the end of the season to keep the crop focused on producing fruit.

You can find more expert advice about pinching out tomatoes and the different growing stages of a tomato plant in Grow Your Own magazine, which is available in all major supermarkets, or on a subscription basis (for more details, click here).

Should you pinch out the side shoots on all tomatoes?

The short answer is: no. Look at the back of your seed packet and see whether your tomatoes are indeterminate (also called cordon) or determinate (varieties that grow like bushes). This is very important to recognise early on as different varieties need different pruning techniques.

Do not pinch: determinate (bush or dwarf)

Varieties such as ‘Tornado’ and ‘Tumbler’ grow to become naturally compact and bushy – any pinching out done to this type will result in lower yields, so it’s vital to maintain the foliage as much as possible.

Yes, pinch: indeterminate and semi-determinate (cordon)

Indeterminate tomato plants such as ‘Gardener’s Delight’ and ‘Ferline’ grow as tall, single-stemmed plants resulting in the need for support from canes and training of the leaves. Semi-determinate will also need pinching, but will grow shorter. This includes varieties like ‘Roma’ and ‘Rutgers’.

How to pinch out tomatoes

Side shoots

Using your thumb and forefinger, pinch the small shoot between the main stem and a truss so it comes away. You can also snap it off if that’s easier.

It’s best to use your fingers rather than secateurs, as the tomato will form scar tissue over the wound more easily and stop diseases coming in. Secateurs can also transfer disease from one plant to another, which could wipe out your whole crop in just a few snips!

It’s also a good idea to do this in the morning, as the plant will be more turgid and the side shoots will snap off easily.

Main stem

Cut the top off the main stem (the growing tip) at a pair of leaves above the highest truss. This will stop the plant growing any higher, and divert its energy into forming tasty fruits.

Pinching out tomatoes: common mistakes

There are two main mistakes you can make when pruning tomatoes.

1. Pinching out a truss instead of a side shoot
The trusses carry the tomato fruits – so if you pinch out the trusses, you won’t get any fruit! Make sure you only pinch out the side shoots, which grow between the truss and the main stem.

2. Pinching out side shoots on bush varieties
Bush varieties (known as determinate varieties) have been bred to be compact plants that have a dense tangle of stems and fruit. Don’t prune these in any way, as you’ll reduce your harvest dramatically.

Find more tomato growing advice and expert tips on how to enjoy a bumper harvest in Grow Your Own magazine, which is published monthly. Or better yet, why not subscribe to the magazine? Find out more by clicking here.