Tomato Troubleshooting

Why do my tomatoes have black, sunken bottoms?

This is blossom end rot, a disorder that shows as a dark, leathery patch on the blossom end of the fruit. Extension sources link it to the plant not getting enough calcium into the fruit, usually because of uneven watering rather than a lack of calcium in the soil.

Water steadily, mulch the bed, and avoid heavy nitrogen feeding. Get a soil test to check pH and calcium before adding anything. Affected fruit will not recover, so remove it and let the plant put its energy into later fruit, which is often fine once watering evens out.

Not every dark patch on a tomato is blossom end rot. Sunscald shows as a pale, papery area on the side facing the sun, and fungal rots can begin at any spot on the fruit. Look closely at where on the fruit the damage sits and how it feels before deciding on a cause.

What causes cracked or split fruit?

Cracking often follows a dry spell broken by heavy rain or a big watering, when the inside swells faster than the skin. Some varieties crack more than others. Cracks can let in rot and insects, so pick split fruit promptly and use it soon.

Steady moisture and mulch are the main defense. Harvesting fruit as it starts to color and ripening it indoors can also save fruit before a forecast storm.

Why are the leaves curling, yellowing or spotted?

Leaf curl is often a response to hot, windy or very wet weather and does not always mean disease. Yellowing from the bottom of the plant upward can come from natural aging, fungal leaf spots, or watering problems. Spots with rings or yellow halos may indicate a leaf disease.

Remove affected lower leaves, keep foliage dry, improve airflow and avoid working among wet plants. If you are not sure, take a sample to your extension office for diagnosis, since the same symptom can have different causes that need different responses.

Take notes through the season on weather, watering and when symptoms first appeared. A hot week followed by a heavy storm, for example, often explains cracking and leaf changes that look alarming but pass. Notes also help an extension educator narrow down the cause when you bring in a sample.

• Check watering first
• Look at both sides of the leaves
• Note whether symptoms start low or high on the plant
• Photograph the problem and the whole plant

Why are there flowers but no fruit?

Tomato flowers often drop when nights are too cool or days are very hot, since pollen does not set well at temperature extremes. Too much nitrogen can also give you big leafy plants with few fruit.

Be patient and keep plants watered. Fruit commonly sets again when temperatures moderate. Avoid the urge to add more fertilizer, which usually makes it worse.

What are the signs of wilting diseases?

A plant that wilts even when soil is moist, or one that collapses suddenly, may have a soilborne disease. These problems can stay in soil for years. Cutting a stem and finding discolored tissue inside is a reason to call for help.

Do not compost infected plants. Ask your extension office about rotation, resistant varieties and whether to send a sample for lab diagnosis.

Some soilborne problems are managed mainly through rotation and resistant varieties, so keep a map of where tomatoes, peppers and potatoes grew each year. Rotating among unrelated crops gives soil time to rest from pathogens that build up when one plant family is grown repeatedly in the same place.

What about insects and holes in fruit?

Large chewed leaves and missing foliage may be caused by hornworms, while small holes can be a sign of other feeders. Many pests are best handled by hand-picking and keeping the garden clean. Identify the pest first, since a treatment for one problem will not help another.

If you consider any spray, the label is the law, and your extension office can help you decide if one is needed at all.

How do I prevent problems next year?

Rotate where tomatoes grow, choose varieties with disease resistance listed on the tag, stake plants for airflow, and water at the base. Clean up plant debris at season's end.

Keep a garden journal with dates, weather and what went wrong. Patterns often show up across seasons, and notes make diagnosis much easier.

Ask a neighbor or local master gardener group which tomato varieties do well in your area. Local experience with disease resistance and weather tolerance is often more useful than a catalog description, and it costs nothing to ask.

Last reviewed: November 12, 2026. Written by the Homestead & Small Farm Editorial Team. See our editorial policy.