Solving and Preventing Common Tomato Plant Problems

Home gardening is a favorite hobby for millions of people around the world. Tomatoes are one of the most popular fruits (or vegetables if you want to engage in that argument) that are grown. They are inexpensive, easy to grow and produce a bountiful harvest of fresh, juicy tomatoes that are a summertime treat.

Unfortunately, tomato plant problems are very common. Problems may include harmful insects, diseases and fungus that can be caused by weather conditions, improper watering, nutrient deficiencies or inherent factors bred into the seeds or plants.

We will explore some of the more common problems home tomato gardeners might face and provide suggestions on how to prevent or solve most of them.

Brown circular area on the blossom-end of the tomato

Symptom: This is a common problem on homegrown tomatoes. It initially appears as a small, depressed, leathery, brownish area on the blossom end of the fruit and grows in size as the fruit ripens. The spot may end up being as large as a dime or half-dollar if left untreated.

Cause: Blossom end rot is caused by a calcium deficiency coupled with wide fluctuations in available moisture. Training and pruning the tomato vines may also increase blossom end rot.

Remedy: Remove the affected fruit so other fruits on the plant will develop normally. Keep the plants well watered. Mulch around the base of the plants to maintain a more uniform moisture supply. Avoid cultivating or hoeing near the roots of tomato plants. Some gardeners also add crushed eggshells to the soil before planting seedlings to fortify calcium availability.

Flowers form but drop before tomatoes develop

Symptom: Tomato flowers fall off prematurely causing very little or no fruit to actually develop.

Cause: “Blossom Drop” is usually caused when the tomato plant experiences a sudden change in the weather, typically earlier or later in the season when night temperatures are lower than 55 degrees F. The heat of the summer is also a common time when this occurs, when day temperatures are higher than 95 degrees F or when night temperatures remain above 75 degrees F. Hot drying winds and a sudden lack of moisture for the plant may also intensify the problem.

Remedy: Add mulch around the to keep the soil moisture even. You can also use a tomato blossom set spray, available from your local garden store. It is an all-natural plant hormone that helps blossoms set fruit in spite of poor weather conditions, producing larger, meatier tomatoes with fewer seeds. Improving weather conditions may also solve the problem without action.

Tomato skin suddenly splits or cracks

Symptom: The skin of the fruit suddenly develops large cracks, most times radiating out from the stem end. Cherry tomatoes are especially vulnerable to this condition, occurring anywhere on the fruit.

Cause: Splitting or cracking typically happens when the fruit experiences accelerated growth which can be brought on by a sudden increase in moisture after being too dry, like a sudden summer rain after an extended dry period. Cracking also may occur when the fruit is overripe.

Remedy: The good news is that splitting or cracking does not affect the flavor and the tomato can still be eaten, however unsightly it may appear. To avoid the problem, provide consistent moisture to the plant or research and select varieties that are resistant to cracking. With cherry tomatoes, pick ripe or nearly ripe fruit right before a forecast rain storm to limit the risk of cracking.

Tomato plants have a stunted appearance

Symptom: Nematodes live in the soil and cause swelling of the plant root which, in turn, causes stunted plants and discolored plant leaves. The only way to confirm diagnosis is to pull the plan and inspect the roots.

Cause: Root-knot nematodes are soil-born microscopic eelworms.

Remedy: The bad news is there is no treatment for an existing nematode infestation. The good news is the affected plants can still grow and produce edible fruit. Preventative measures to stop nematodes in the future include selecting varieties labeled with “N” and planting marigolds with your tomatoes. Many varieties of marigolds, including’ Nema-gone’, ‘Golden Guardian’, or ‘Tangerine’, release a chemical into the soil that kills nematodes.

Visibly chewed leaves and tomatoes

Symptom: Chewed up plant leaves and damaged fruits that are still unripe are clearly visible.

Cause: Tomato hornworms are large, green-grayish caterpillars that feed off of tomato fruits and plants.

Remedy: Although they can blend very well with surrounding foliage, once discovered, they can be easily picked off by hand and disposed of.

Although some of the more common tomato plant problems have been highlighted, it is important to remember that there are many more diseases and pests that may affect your plants. If you have a problem that you can’t easily diagnose, please check with your local extension agent or garden center to learn what treatment is best for your specific problem.