How to prune tomatoes in a greenhouse

To achieve a high tomato yield, you need to know proper growing techniques. These include pinching out side shoots, a mandatory procedure for most tomato varieties and hybrids.

What is pinching and why is it necessary?

During the growing season, tomato plants actively develop lateral shoots and leaves. Vigorous indeterminate tomatoes, characterized by unlimited growth, branch especially extensively. These plants are not only tall but also heavily foliated, with numerous lateral shoots.

A characteristic feature of this plant is the appearance of lateral shoots in the leaf axils. The leaf itself grows first, and only then does the branch emerge. This lateral shoot is called a side shoot, and it is this shoot that should be removed.

Side-sonning is the removal (cutting or breaking off) of excess shoots growing in the leaf axils. These shoots quickly gain length and require nutrition, moisture, and sun, thereby taking all of these from the fruiting branches.

A tomato plant with shoots sprouting from its branches resembles a green, branching tree, but this is hardly a joy. An imbalance between the fruit clusters and the foliage develops, ultimately leading to reduced yields.

Side shoots emerge from each axil, develop, and produce new leaves, which also develop lateral shoots. This development requires nutrients, which significantly slows fruit formation and ripening. The plant is unable to provide the required amount of nutrition to the tomatoes, as most of it is "taken up" by the growing shoots. Not only does the yield decline, but so does the quality of the fruit.

Insufficient nutrition leads to small tomatoes, which take a long time to ripen on the vine. Indeterminate tomatoes left unpruned create a veritable "jungle" in shelters, starving the fruit on the vines of not only nutrition but also light.

Experts have found that removing side shoots accelerates tomato ripening by 12-14 days. This is especially important for regions with harsh climates and short summers. Only the "essential" branches, flower and fruiting clusters, and side shoots, which serve as additional stems, remain on the bush.

Thanks to this simple but responsible procedure, the overall yield increases and the taste of the fruit improves.

Stepson or fruit cluster – how to distinguish

It can be difficult for inexperienced gardeners to determine where the stepsons are on a tomato plant and how to avoid removing useful fruit-bearing branches instead.

Main differences:

• a stepson always grows from the axil of a leaf, and a brush - only from the stem of the plant itself;
• Leaves are forming on the stepson, but the fruit cluster does not have them, but the forming buds are immediately visible.

When removing side shoots, it is recommended to remove lateral shoots that have reached 4-5 cm. At this time, the leaves on the side shoots are clearly visible and are easy to distinguish from the fruit clusters.

Time for pinching out stepsons

The best time to begin removing lateral shoots is when the first tomato cluster emerges during flowering. Offshoots form in the leaf axils and quickly gain strength, so these should be carefully removed.

How to prune out stepsons correctly?

Remove side shoots by hand or with a sharp knife. Breaking them off by hand is preferable, but be careful to hold the main stem of the plant and avoid peeling the skin off the stem. Pinch the shoot, leaving a stub.

Avoid getting sap from the wound on your hands, as it can transfer viruses to other plants during pruning (if the plant is unhealthy). When using tools (scissors, knife), also be careful not to cut the tomato stem or leaf along with the pruned tomato, which could damage the plant. Sharpen the tools, and remove the pruned tomato quickly, leaving a stub up to 1.5 cm long.

After removing the side shoots in the leaf axil, disinfect the knife or scissors in a weak solution of potassium permanganate. Disinfection prevents the transfer of possible infections from one plant to another.

Greenhouse Tomatoes: Bush Formation

Any greenhouse has limited space; when planting tomatoes, its dimensions (height, width of the structure, length of the beds) must be taken into account and the distance between the holes must be maintained.

Tomato descriptions (especially indeterminate varieties) always include a recommended planting pattern per square meter. Most tomato descriptions also recommend growing the plants in single, double, or multiple stems.

For greenhouse tomatoes, removing side shoots and shaping the bushes according to a specific pattern is a necessary technique to ensure plant development, air access, adequate nutrition, and good lighting. Three main methods of shaping bushes are practiced: leaving one "trunk," two, and three.

The choice is explained by the characteristics of the variety or hybrid of the crop, as well as the growing conditions.

Formation into 1 stem

This method is considered the simplest, as there's no need to calculate the number of lateral shoots. The main thing is to correctly identify the side shoots and remove them promptly. In such bushes, fruit clusters form only on the central stem; all shoots growing from the axils are broken off.

First, remove the shoot under the first inflorescence when buds are forming. It usually grows strong and vigorous, but don't let it outgrow. Break off the shoot before it reaches more than 4-5 cm.

Leaves below the first cluster are also removed, but gradually, 1-2 leaves at a time. By the time the tomatoes on this first fruiting branch ripen, all leaves should be removed from the stem below.

Growing tomatoes in a single "trunk" is an option for large polycarbonate shelters with tall varieties that require ample space, light, and air. Removing excess shoots improves ventilation and light exposure for the plants in the shelter, and fruit formation and ripening are faster.

Formation in 2 stems

What should you do if the seed packet for a specific tomato variety recommends training the plant into two stems? Of all the shoots, you should leave one, the strongest and most vigorous side shoot, which will act as an additional stem.

All remaining shoots in the leaf axils are regularly removed. With this method of training, the tomato bush is branched and wide, with clusters of fruit forming on a secondary stem in addition to the main one.

A lateral shoot growing beneath the first inflorescence is chosen as the second "trunk." It grows below the cluster and is distinguished by its strength and thickness, and in many varieties, the stem appears to bifurcate as it grows.

This method of cultivating greenhouse tomatoes is the most popular among gardeners, as almost all varieties, with very few exceptions, are suitable for it.

Formation in 3 stems

This "three-stem" bush formation method is similar to the previous one. Along with the main stem, the bush produces flower clusters with two additional side shoots. When selecting shoots, leave one side shoot under the first inflorescence (as with a two-stem formation), as well as another one growing higher up the stem.

Lateral shoots from the axils of other leaves are regularly removed. With this method, bushes are planted more spacingly, maintaining proper spacing, as the plants are characterized by their lushness, with numerous lateral shoots and flower clusters.

Peculiarities of the formation of different varieties of tomatoes

When growing tomatoes, gardeners use different methods of formation, taking into account such parameters as limited and unlimited growth.

Formation of indeterminate varieties

Indeterminate tomato varieties and hybrids are distinguished by their vigor, unlimited growth, and a large number of regularly growing lateral shoots.

The first cluster of flowers appears after approximately 9-12 leaves, and side shoots begin to emerge from the axils at the same time. Without pruning, the bush grows extensively, and flowering and fruit formation slow down, as the foliage consumes a large portion of the plant's nutrients.

Therefore, indeterminate varieties are formed by removing all side shoots and leaving the central trunk. The stem grows upward without restriction; when it reaches the trellis, it is bent and released downward. About a month before the end of the growing season, the top of the main stem is pinched. In temperate climates, pinching is done in mid-August, while in northern regions, pinching is done earlier, in early August. The timing is determined not only by the climate but also by the condition of the plants and growing conditions. In heated greenhouses, fruiting continues until November, so pinching is done later.

Formation of semi-determinate varieties

Semi-determinate varieties have their own characteristics, located between indeterminate and determinate tomatoes.

1. These are varieties and hybrids of the generative growth type, prone to the formation of a large number of fruits.
2. The plants have a reduced distance between brushes - 12-16 cm, so more flower brushes grow on the stem up to the trellis.
3. From 8 to 12 inflorescences are formed on the bush, but if there is insufficient nutrition, the half-flowering plants suddenly stop growing, and then, in the absence of a reserve (additional) stepchild, the overall yield decreases.

Based on the growth characteristics of semi-determinate varieties, it is recommended to grow them in two or three "trunks." The following options are available:

• a stepson is left under the first formed inflorescence, the central stem is pinched after 5-6 flower clusters have formed on it;
• two additional lateral shoots are left, choosing the strongest ones, the growth point of the main stem is topped after 4-5 inflorescences appear on it.

On semi-determinate tomato bushes, at least one additional shoot is always left to replace the main stem.

Formation of determinate varieties

A characteristic feature of determinate varieties is their self-limited growth. The bushes are compact and medium to short in height, so the plant's shaping method is chosen based on the variety, weather, and growing conditions.

For early harvests and rapid ripening of the fruit, growing in a single "trunk" is suitable. The total number of fruits per bush is small, but gardeners harvest red tomatoes early.

When cultivating determinate plants with a central stem, it is recommended to increase the number of bushes per square meter. Plants are arranged in rows, with up to six bushes per square meter.

Planning to plant the seedlings and train them into two "trunks" with one side shoot left will yield more fruit, but the ripening time will be delayed (by approximately 10-14 days). If the stem doesn't complete itself, pinch it back in August.

Leaving three "trunks" on the bush yields the best possible harvest, but not an early one. As the fruit sets and ripens, two additional side shoots with inflorescences grow on the clusters of the central stem. These side shoots take up some of the nutrients, which slows ripening. However, this is compensated for by the large number of tomatoes per plant, which ripen after harvesting indoors.

Tomatoes grown in open beds are formed into 1-2 stems. Superdeterminate tomatoes are left with one extra side shoot, and the others are removed.

Modern low-growing hybrids are grown in ridges without pinching, or by removing lateral shoots from the leaf axils before the first inflorescence.

Stepsoning using the Kizima method

Gardening enthusiasts take a creative approach to growing tomatoes, experimenting with various techniques. Renowned experimental gardener Galina Kizima offers her own method for shaping tomatoes.

The idea is to leave two stems on tomatoes with limited growth, while all other varieties only have one. Excess side shoots are removed to prevent them from growing too large. As the fruit ripens, the leaves under each inflorescence are removed. At the end of July, all tomatoes with unlimited growth are pinched.

The method involves reducing watering and is more suitable for regions with dry summers. In the Northwest and Siberia, where the summer season is unpredictable and rains are frequent, Kizima's method is less effective.

When growing tomatoes, pinching out side shoots is an important technique that allows you to increase the overall yield of fruits from a bush and improve the taste of ripe tomatoes.