Tips for Pruning Tomato Plants

Generations of gardeners have scrupulously pinched and pruned their tomatoes to encourage abundant large, evenly-sized fruit production. However, pruning tomatoes has recently become controversial, mainly because it is said to open the door to disease.

This post will help you understand the issue and decide whether or not to prune your tomatoes. You may want to grow several plants of the same variety and prune only part of them to make your own opinion.

Let’s start by looking at the advantages and disadvantages of pruning tomatoes.

Advantages of pruning tomatoes

Pruning limits the natural exuberance of tomatoes:

It prevents plants from becoming so exuberant that they get in the way of each other.

It facilitates staking and cultivation.

It gives the garden a neat appearance.

The fruits mature earlier.

The fruits are larger and more homogeneous in size.

Harvesting is made easier because the fruits ripen at the same time.

Disadvantages of tomato pruning

Pruning puts repeated stress on the plants, making them less resistant.

Pruning causes wounds that are open to diseases, especially mildew.

Removing leaves reduces photosynthesis and, therefore, the sugar supply of tomatoes.

Distinguish between pruning tomato varieties

Tomato varieties that do not prune

Some varieties of tomatoes do not need to be pruned. These are:

• cherry tomatoes;
• the so-called “determinate” varieties are compact, bushy varieties that stop growing by themselves beyond a certain size. Such varieties include Roma VF, Banana Legs, Tribeca, and Esmeralda, among others…

Tomato varieties that can be pruned

On the other hand, the varieties known as “indeterminate”, the most numerous, have an exuberant growth, becoming taller and bushier, almost without limit: these are the ones that are pruned by constant disbudding.

Case 1: Prune tomatoes in a classic way

Prune your tomatoes (with indeterminate growth) in a traditional way if:

you have limited growing space, especially if you grow tomatoes in a greenhouse;

you want to produce tomatoes that are as big as possible;

you prefer to harvest ripe tomatoes simultaneously and thus facilitate harvesting.

In this case:

Systematically practice disbudding by regularly pinching the gourmands.

If necessary, perform topping in August.

If necessary, thin out the leaves from the end of August.

Note: to limit the appearance of diseases, always prune in dry weather and promote healing by applying a green clay slurry.

1. Classic pruning: disbudding tomatoes

The purpose of disbudding is to remove the suckers, i.e. the secondary stems that grow from the leaf axils, to keep only the main stem or mother stem.

To remove the suckers:

If they are young, still in the state of 2-3 cm buds, pinch them with the tip of your nails with a sharp blow.

If more developed, prune them with a pruning shear disinfected with methylated spirits.

Note: disbudding should be done about once a week as new buds appear.

2. Classic pruning: head off the tomatoes

Classic tomato pruning also includes topping the main stem towards the end of the season to prevent it from weakening by producing tomatoes that will no longer have time to ripen.

To do this:

• Intervene during August.
• Pinch or prune the end of the main stem after the 4th or 5th bunch of flowers.

3. Classic pruning: remove the leaves from tomatoes

The leaf removal of tomatoes meets two different needs:

To remove the leaves in contact with the soil, and therefore wet, to avoid the appearance of diseases.

To remove the excess leaves that prevent the sun from shining through at the end of the season to help the last tomatoes ripen.

The first operation is strongly recommended.

The second one is optional, depending on your region and sunshine. If you do it, remove the leaves just above the fruit towards the end of August to better expose them to the sun.

Note: Avoid removing too many leaves at once to avoid weakening the plant.

Case 2: Try unsized tomatoes

Try not pruning tomatoes (indeterminate) if:

• you have all the space you need to space your tomato plants widely;
• you want to treat your tomatoes as little as possible;
• you accept a jungle-like garden.

In this case, be sure to plant your tomato plants far apart and do not try to stake them in the traditional way (you would need giant stakes):

• Space the plants widely at planting: unpruned, your tomatoes will grow exuberantly: leave a spacing of at least 1 meter, or even 1.50 m, between 2 plants and between rows to ensure good air circulation between the plants.
• Use a cage instead of a stake: place a large-mesh cylinder of wire mesh around each plant, about 70 cm in diameter and at least 1 m high. This will allow the plant to grow freely but keep the leaves and fruit above ground as much as possible.

Note: even if you choose to prune, remove the leaves that touch the ground and the leaves that touch the neighbouring plant to limit the occurrence of diseases.

Materials needed to prune tomatoes

Rubbing alcohol

Green clay

Pruning shears