Tomatoes are species of herbaceous annual and perennial plants belonging to the Solanum genus of the Solanaceae family.
To maintain tomato plants, one task gardeners should carry out is pruning. There are a number of reasons why, for certain types of tomatoes and at certain times, pruning can be beneficial.
Pruning can help make sure that plants have adequate airflow and are not overcrowded. It can ensure good quality fruits, keep plants healthy and it may help to increase the yield of ripe fruits towards the end of the growing season.
Julia Omelchenko, resident botany expert for the Plantum app told Express.co.uk that it’s “essential to water, fertilise, and prune tomatoes promptly” for “maximum yield”.
The expert said: “Pruning is an essential aspect of tomato cultivation. It improves the quality of your tomatoes and serves as an important measure against various diseases and pests.”
She claimed that there are many benefits to pruning tomatoes. The main reason is to remove unnecessary parts of the plant that consume energy, water, and nutrients “without contributing significantly to fruit production”. This primarily refers to the offshoots (suckers) that grow between the stem and the branches.
The expert warned: “Allowing these shoots to grow diverts the plant’s energy from fruit production and promotes excessive leaf growth. Later, these shoots may also bear flowers and fruit, but the fruit will be small and not as sweet and juicy.”
Excessive offshoot growth also leads to overcrowding of the bush. The primary purpose of the leaves is to produce energy through photosynthesis, which requires sufficient sunlight.
With an overcrowded bush, the leaves may not receive enough sunlight, which “negatively affects the speed and quality of ripening”. Overcrowded bushes need to be pruned to boost the “speed of ripening”.
Overcrowding can also lead to increased humidity and reduced air circulation. Many fungal pathogens thrive in these conditions. Therefore, sucker removal reduces the risk of fungal diseases such as late blight, Cladosporium leaf spot, early blight, Septoria leaf spot, and others.
Gardeners should also remove the lower leaves that come in contact with the soil as a preventative measure. It’s important that gardeners remember that there are determinate and indeterminate types of tomatoes.
Determinate tomatoes are called so because their height and lifespan are limited. They have an upper inflorescence that the bush won’t grow beyond.
Determinate tomatoes are compact and well suited for regions with short summers, as they reach a height of about 30 to 70 cm and have a short fruiting season, after which they gradually fade.
Pruning these tomatoes involves removing branches that grow in the shade and don’t have flowers. By pruning, Julia said: “You will make the bush look more compact, ensure an even distribution of green mass, and allow all leaves to receive oxygen and sufficient sunlight.”
Indeterminate tomatoes, as the name implies, have no upper inflorescence. Therefore, they have a longer growth and fruiting period and can grow up to 200 to 300 cm tall. Indeterminate tomatoes are well suited for greenhouses and regions with long, warm summers.
Indeterminate tomatoes have a thick main stem from which all other branches grow. The expert urged: “Don’t touch it and prune only the side branches, otherwise upward growth will stop.”
Other than that, gardeners can follow the pruning rules for determinate tomatoes, which is to remove the flowerless shoots that make the bush too dense and prune branches and leaves that touch the ground.
As with pruning any other plant, gardeners need to always use clean, sharp scissors or pruning shears. To avoid introducing fungal or bacterial pathogens into the wounds, disinfect the pruning tool with rubbing alcohol or a potassium permanganate solution. Julia recommends treating the cuts with a weak solution of potassium permanganate or activated charcoal powder.
Be careful not to prune excessively and remove the branches with lots of flowers and leaves, as this “will hinder fruiting” and cause “significant stress” for the plant. Leaves are responsible for energy production, and if there are too few of them, “there won’t be enough energy for normal plant growth and fruiting”. The bush should be evenly covered with branches and leaves.