7 Reasons Your Tomato Plant Is Dying—and How to Save It

Tomatoes can be one of the most rewarding things to grow in your garden. They’re such a treat to add to summer salads or hamburgers during a backyard barbecue—and they make a great gift to share with neighbors or friends. But if your tomato plant is struggling, all that potential excitement can quickly turn to disappointment. If your tomato plant is looking like it’s going to let you down this season, don’t give up hope just yet. We went to the experts to learn all the reasons your tomato plant might be in trouble and how to save it.

Initial Signs Your Tomato Plant is Struggling

Before your tomato plant starts declining, there are signs you can watch out for that indicate it’s in trouble. It’s good to inspect your plants for various signs of disease, pests, and other problems that can be the cause of their distress. Here are some tell-tale signs that your tomato plant needs help:

• Yellowing leaves
• Brown spots on leaves
• Poor growth
• Chewed leaves, holes, or sticky residue
• Visible pests
• No fruiting

Common Reasons Your Tomato Plant Is Dying

Now that you know the main signs to watch out for, let’s dive into the common reasons experts say your tomato plant might be dying. 

Overwatering or Underwatering

Providing the right amount of water is key to healthy tomato plants, and overwatering or underwatering can be the reason it’s dying. It can be easy to overwater your plants, or even forget to hydrate them altogether.

Melvin Cubian, a certified botanist from the PlantIn app, says that if your tomato plant is showing signs such as general wilting, yellowing leaves, and brown edges, these can be signs of watering issues. This is quite common if your plant is grown in a pot or, if grown in beds, it lacks mulch, which helps retain soil moisture.

“You will need to adjust the watering depending on the plant’s needs, the soil moisture, and the weather,” he says. “Check soil moisture regularly, about every other day, to ensure you never miss a watering schedule.”

If the top inch of the soil is dry, that means it’s time to water, Cubian explains, adding that it’s important to ensure containers or garden beds have good drainage. And don’t overcompensate for underwatering issues. “Slowly reintroduce moisture to avoid shocking the plant,” Cubian says.

Pests

Jane Dobbs, expert gardener and gardening team lead at Allan’s Gardeners, says a common reason your tomato plant could be dying is due to pests. “It’s a sure sign that your plants are infested with pests if you find chewed leaves, holes, sticky residue, or visible insects, like aphids, hornworms, whiteflies, or spider mites,” she informs.

She advises using neem oil, insecticidal soap, or handpicking large pests to eradicate them from your plants. Another tip she recommends is adding basil or marigolds with your tomato plants because they are good companion plants for insect deterrence.

Fungus 

Tomato plants can be susceptible to fungi, which can be another reason why your tomato plant is dying. “Each fungal disease may have different symptoms, but the most common signs include brown or black leaf spots, yellowing lower leaves, and sudden leaf drop,” Cubian says. “Severe fungal infections can have yellowing that starts on one side of the plant or leaf, wilting during the day, and browning inside the stem tissue.”

The solution to ridding the fungus is to remove and discard any infected foliage by burning or burying it to stop the spread. You should also improve air circulation by spacing your tomato seedlings properly before planting.

If you notice brown spots on lower leaves, Cubian says you need to cut them off the plant. You should also avoid overhead watering and water early in the day. He recommends applying a fungicide approved for edible plants or trying an organic solution like neem oil to kill fungus.

“Unfortunately, fungal wilts caused by the fungus Fusarium or Phytophthora are incurable, like bacterial wilts, in case the symptoms are at a later stage,” Cubian says. “To save healthy plants, it is best to just remove the sick ones.”

Bacteria

One of the worst reasons your tomato plant is dying can be caused by bacteria. Cubian states that if bacteria is present the whole plant will have sudden wilting regardless of proper watering, and usually will start in the early to mid-fruiting stage. You’ll notice brown discoloration inside the stem when cut, and no yellowing before collapse.

“During the early signs of wilting, the plant may be able to survive, especially when it’s already fruiting,” he says. “You can drench copper fungicides directly into the base, following the brand’s recommended dosage.”

However, he warns that bacterial wilt is incurable once the plant shows extreme wilting. You’ll need to remove and destroy infected plants immediately to prevent the spread, especially if you have several more plants in the next row.

“Avoid planting tomatoes in the same area for several years,” Cubian says. “Practice crop rotation and improve soil drainage by adding compost or earthworm castings to discourage bacterial buildup.”

Nutrient Deficiency

Dobbs says that nutrient deficiency and too little potassium or phosphorus will result in poor fruiting, weak plants, and yellowing leaves.

Cubian states that deficiencies rarely kill the plant, but you will likely harvest nothing if not addressed. Your plant will show signs of deficiency, but it depends on what element is lacking. He says that common signs to watch for are yellowing leaves starting from the bottom, purpling or browning of leaf edges, stunted growth, or poor fruit production.

“Tomatoes are heavy feeders and need balanced nutrients,” he says. “Use a tomato-specific fertilizer rich in nitrogen, phosphorus, and potassium.” You will need to adjust the amount according to what the plant needs.

“Mulching with compost or worm castings can help gradually restore soil fertility. Before planting, it is also important to prepare the soil well by mixing lots of organic matter, which aids in the absorption of nutrients and improves the soil texture ideal for root growth,” he informs.

Extreme Temperatures and Improper Lighting

Similar to watering, tomato plants need the correct amount of light and stable temperatures. Dobbs states that extreme temperature changes can stress the plants, causing flowers to drop and slow growth. “You should use shade cloths during high temperatures,” she advises. “If temperatures drop below 10°C, cover plants with row covers or frost blankets,” she advises.

Cubian says excessive sun exposure is quite common in semi-arid or tropical areas where the dry and hot weather can lead to leaf scorch, sunburned fruit, wilting during the day, or blossom drop.

“Water early in the morning to help plants cope with heat stress,” he says. “You can also apply mulch, like shredded bark, grass hay, or compost to keep the soil cool and moist. Avoid fertilizing during extreme heat, as it can exacerbate stress.”

Poor Soil Conditions

If your tomato plants seem stunted and aren’t producing fruit, it can stem from poor soil conditions. Dobbs says that poor growth is caused by soil imbalance when the pH is too low or too high. You can amend with lime to raise pH or sulfur to lower pH. Ideal soil pH for tomatoes is 6.0-6.8.

The best way to determine what your soil lacks is to perform a soil test. That way, you can ensure you amend the soil with the proper nutrients and avoid overfertilizing your plants with the wrong elements.