Grow · field guide

Common Tomato Problems and How to Fix Them

Tomatoes are the most-grown garden crop and the most-asked-about, because a lot can go wrong. The good news: the common problems have clear causes and simple fixes. Here are the five you are most likely to see and what to do about each.

Ripe red and green tomatoes on a healthy vine

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Sunken brown bottoms (blossom end rot)

A dark, leathery patch on the bottom of the fruit is blossom end rot. It is not a disease or a bug. It comes from uneven watering, which blocks the plant from moving calcium into the fruit.

Fix it with steady moisture: water deeply and evenly, and mulch to hold water in the soil. A drip line on a timer makes this nearly automatic.

A ripe tomato on the vine with the dark sunken patch of blossom end rot on its bottom end
A ripe tomato on the vine with the dark sunken patch of blossom end rot on its bottom end

Cracked and split skins

Cracks appear when a dry spell is followed by heavy water and the fruit swells faster than its skin. The fix is the same as above: keep moisture even, and pick ripening tomatoes before a big rain.

A ripe tomato with a deep split running from the stem
A ripe tomato with a deep split running from the stem

Spotted, yellowing leaves (blight)

Yellow lower leaves with brown spots that creep upward are usually early blight or septoria leaf spot, fungal diseases that splash up from the soil.

  • Water at the base, never over the leaves.
  • Mulch to stop soil from splashing onto the plant.
  • Space plants 24 inches apart for airflow, and remove affected lower leaves.
A tomato leaf with the brown bullseye-ring spots of early blight
A tomato leaf with the brown bullseye-ring spots of early blight

Hornworms and other pests

Big green caterpillars that strip leaves overnight are tomato hornworms. Handpick them; they are easy to spot once you look. For most tomato pests, a barrier beats a spray, so a light insect cover early in the season prevents more than chasing bugs later. If you do spray, an organic option like neem needs repeating every 1 to 2 weeks to work.

A tomato hornworm caterpillar feeding on a tomato plant
A tomato hornworm caterpillar feeding on a tomato plant

Big plant, no fruit

A lush green tomato with no fruit usually means too much nitrogen or too little sun. Ease off high-nitrogen fertilizer, which pushes leaves over fruit. And make sure the plant gets 6 to 8 hours of direct sun. Very hot nights above 75 F can also pause fruit set until it cools.

Yellow tomato flowers on a leafy plant, the stage before fruit sets
Yellow tomato flowers on a leafy plant, the stage before fruit sets

Keep going

Questions, answered straight

What causes the bottom of my tomatoes to rot?

Blossom end rot, from uneven watering that blocks calcium uptake. The fix is steady moisture: deep, even watering plus mulch. It is not a disease and does not spread.

Why are my tomato leaves turning yellow with spots?

Usually early blight or septoria, fungal diseases splashed up from the soil. Water at the base, mulch, space for airflow, and remove the affected lower leaves.

Why does my tomato plant have no fruit?

Too much nitrogen, too little sun, or very hot nights. Cut back high-nitrogen feeding, ensure 6 to 8 hours of sun, and wait for nights to drop below about 75 F.

How do I get rid of tomato hornworms?

Handpick them, which is the fastest fix for a home garden. To prevent pests in the first place, use a light insect cover early. Neem can help but must be reapplied every 1 to 2 weeks.

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