Methods to Look after Tomato Vegetation: Pruning, Trimming, Bug Management


Tomatoes are often the staple food in any home vegetable garden, and there are many reasons for this.

The fruit (often mistakenly viewed as a vegetable) is tasty, relatively easy to grow, and a versatile ingredient in cooking and salads.

Once considered poisonous, the tomato is now a popular choice for vegetable gardens in the United States, with thousands of varieties to choose from.

After planting the seedlings, it is important to give the tomato plants proper care and attention, including regular pruning, trimming, and insect control.

Tomatoes are delicious, relatively easy to grow, and can be used as a versatile ingredient in cooking and salad.
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Pruning and trimming tomato plants

“Everyone loves growing tomatoes,” Craig LeHoullier, a tomato grower, self-described “tomato nut,” author of Epic Tomatoes and co-host of Tomatopalooza told Newsweek.

“But the cultivation areas (climatic zones / weather) and the methods (garden, raised beds, containers, straw bales) are very different. There are literally thousands of varieties of tomatoes – and whether they are large (indeterminate) or small (determinate or dwarf) means a lot in terms of how they need to be supported. “

A good place to start is to remember that tomatoes need a lot of space to spread and grow, as crowded conditions can stunt their growth and lead to disease.

Fine Gardening magazine advises that each leaf on a tomato plant should have plenty of room and support from the ground to maximize photosynthesis efficiency and minimize the risk of disease.

Space to grow

If the tomato plant grows too dense or if it is forced to lie on the ground, many of its leaves are deflected into the shade, which greatly reduces sugar production and thus its ability to grow.

An overgrown plant also reduces airflow and provides an environment for disease to thrive, advises Joe Lamp’l, gardening expert and host of the PBS series Growing a Greener World.

“Moving air dries out the plant leaves, which is important for combating disease,” says Lamp’l in his Tomato Growing Advice podcast. “Airborne pathogens can simply blow through in dry conditions. However, when the plants are wet from morning dew, rain, or overhead watering, the fungal spores cling to the damp leaves. So tuber blight, Septoria leaf spot and a few other tomato diseases will arrive. “

Cherry tomato plant
Tomatoes need a lot of space to spread and grow as crowded conditions can stunt their growth and lead to disease.
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Pruning of leaves and shoots

A good rule of thumb is to be careful when your tomato plant reaches about 3 feet in height, as the leaves should be removed from the bottom of the stem. This is because they are the oldest leaves on the plant and sit at the base of the plant stem and receive the least amount of sun and airflow. This can lead to potential fungal growth.

Removing and pruning the lower leaves of a tomato plant will help prevent fungal diseases. If the leaves begin to turn yellow below the first flowers, this can be a useful indicator of when to start pruning.

It is also recommended to cut leaves as soon as spots or deformations become visible to protect the rest of the plant from possible fungal disease.

“Suction cups” or “sprouts” that grow at the step of two branches can also be removed from plants so that they “do not become top-heavy and fall over,” advises LeHoullier.

These growths will also not bear fruit, and it is believed that they could draw energy from the rest of the plant.

Tomato seedlings
A man who planted tomato seedlings in the greenhouse of a domestic vegetable garden.
Jill Ferry / Getty Images

However, an Iowa State University study published in 2000 found that pruning tomato suckers sometimes and sometimes didn’t make a difference in terms of the size of the fruit being grown.

By thinning out some of the leaves, the sun can also better reach the ripening fruit.

Former Cornell Cooperative Extension Horticulture Educator and Master Gardener Marie Iannotti told The Spruce that it is the leaves that give tomatoes flavor through photosynthesis and making the sugar. According to this logic, fewer leaves could mean less sweet tomatoes.

As the plants grow, tying the main stems to stakes will better support the plants.

Most tomato varieties require some form of assistance, explains LeHoullier. Indefinite varieties will continue to grow and bear fruit until they are killed by a severe frost. Certain varieties stay smaller – only about 3 feet tall and 3 inches wide – but they all make their fruit in a short amount of time, and the weight can put a heavy strain on the branches of the plant.

Supporting tomato plant growth also keeps foliage elevated, lower risk of disease, and protecting tomatoes from pests.

Tomatoes grow on a vine
Tomatoes grow on a vine at a Dutch stand at the Green Week agricultural fair on January 17, 2020 in Berlin.
Sean Gallup / Getty Images

Plant diseases

Tomatoes are susceptible to a variety of potentially harmful diseases from airborne pathogens, soil-borne bacterial and fungal diseases.

One of the most common diseases affecting tomato plants is Alternaria, also known as early tuber rot, which causes dark spots on the leaves. The spots can spread to the stem of a plant, which can be fatal. Late blight, a water mold that attacks leaves, stems, and fruits, shows up in brown spots on the leaves and brown rotten fruits.

Inga Meadows, a vegetable pathologist at North Carolina State University, believes that all tomato disease problems start in the environment.

“At the Eastcoast [of the U.S.], warm temperatures, high humidity, frequent rainfall and heavy dew create conditions ripe for fungi and bacteria, “she explained on Lamp’l’s Tomato Disease Prevention & Control Podcast.

Disease control

Meadows suggests a helpful way to understand why plant diseases arise in what she calls the “Disease Triangle,” where the three points of the triangle are the host, pathogen, and environmental conditions.

If all three are present, then a disease problem is “very likely,” she says.

Meadows recommends growing tomatoes in a raised bed, starting with clean soil or potting soil that is free of soil borne pathogens.

She also advises starting healthy transplants from the grower or greenhouse. “If you’re in one of your garden centers and want to buy a spotted tomato plant, don’t – resist,” she adds.

Tomato pest
A farmer shows a tomato damaged by the insect Tuta absoluta.
Costas Metaxakis / Getty Images

Meadows also suggests a crop rotation strategy to give the soil a break from a particular crop family every two or three years so that pathogens don’t build up in the soil.

Using a drip irrigation system or soaking hose is helpful in restricting water to only the roots where the plants really need it. Otherwise, apply water at ground level to prevent the foliage themselves from getting wet, creating an ideal environment for bacteria and fungi.

Simple techniques like removing noticeably affected leaves and disposing of them can slow the spread of disease or completely remove an affected plant.

Commonly available fungicidal or bactericidal sprays must be used before the disease appears to be effective. The sprays cover the leaves and prevent a pathogen from infecting the leaf.

Insect and pest control

Pests and diseases can infect a tomato plant if proper care and attention are not observed. Pests such as aphids, groundworms, flea beetles, and hornworms can devastate tomato plants, with some worms being able to eat an entire plant in a matter of hours.

Hornworms are the larval stage (caterpillars) of sphinx moths and are called hornworms because of their telltale horn or tip on their tail.

These caterpillars have voracious appetites and can eat whole leaves and small stems in a short amount of time, warns the Missouri Botanical Garden and the William T. Kemper Center for Home Gardening.

A hornworm caterpillar with wasp eggs on its back can be seen on a leaf. Hornworms can eat whole leaves and small stems in a short time.
Jim Lane / Getty Images

Aphids are sucking insects that are carriers of plant diseases, explains garden expert Lamp’l on his website Joe Gardener. However, they can be easily controlled by knocking them off the plants with a sharp jet of water or insecticidal soap.

The tomato fruit worm can also leave visible black holes at the base of the fruit stem.

To best combat pests, experts recommend daily monitoring tomato plants, checking under the leaves, checking the fruits themselves and checking near the ground.

Small sucking insects like aphids and mites can be tempered with a variety of naturally-based insecticides and insecticidal soaps, while larger beetles like hornworms and stink beetles can be hand-picked.

A ripe tomato hangs from a tomato plant in a front yard.
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