Tomato Plant Leaves Curling? 7 Possible Causes & What to Do

Tomato plant leaves curling can be a serious concern for any gardener. Noticing the vibrant green leaves of your tomato plant curling can raise many questions.

Of course, it can be challenging to grow perfect tomatoes—sometimes, they have problems, one of which is leaves curling.

While leaf curls on tomato plants do not mean the plant is dead, determining the cause earlier can help treat the problem. Keep reading to discover why tomato plant leaves curl and what to do about it.

7 Reasons Why Tomato Plant Leaves Curl

Tomato plant leaves curling can be caused by several factors – some are serious while others are not. Here are seven reasons that might cause leaf curling in your tomato plants and how to fix them.

01. Environmental Stress

Extremely high temperatures and strong winds can cause tomato plant leaves to curl. Although tomato plants thrive well in warm weather, high temperatures above 90 F (32 degrees C) can cause the leaves to curl to conserve moisture.

How to Fix this:

If you live in areas with extremely high temperatures and strong, dry winds, plant your tomatoes in the shade or move them to a shady place when temperatures are high and the winds are strong.

02. Overwatering and Underwatering

Tomatoes need more water to grow healthy and produce fruits. However, too much or too little water can lead to leaf curl. Overwatering can suffocate the roots, preventing them from taking up nutrients, thus leading to leaf curl.

Additionally, if your tomato plants are not receiving enough water, the leaves will curl to retain water.

How to Fix This:

Overwatering – Only water your tomato plants when the topsoil is completely dry. You can insert your finger about an inch deep to check whether the soil is dry.

Underwatering – Water deeply and consistently and ensure the soil is well-draining to avoid waterlogging. You can use some watering strategies like watering early in the morning when the temperatures are cool so the plant can benefit from the water before it evaporates.

In addition, consider using drip irrigation to maintain even soil moisture. Also, add some mulch (hay or dried-up twigs) around your plants to conserve moisture.

03. Transplant Shock

Transplant shock occurs when a plant is moved to a new location, causing it to experience stress as it adapts to its new environment. This is common for tomato plants, especially when transplanted from seed trays or pots to the garden.

The process of transplanting the plant causes root disturbance and temperature fluctuations, causing the leaves to curl as they try to adapt to their new environment.

How to Fix This:

Tomato plants that curl their leaves due to transplant shock often recover after several weeks – just provide plenty of water.

However, to minimize transplant shock, gradually expose them to the outdoor environment for several days before transplanting them outside. Transplant your tomatoes early in the morning or afternoon when the temperatures are cool to reduce stress.

04. Pests and Viruses

Pests such as broad mites can also cause tomato plant leaves to curl. Broad mites inject toxic saliva into the tomato leaves, causing them to curl. They are microscopic so they are hard to see with the naked eyes.

There are two common tomato viruses that cause tomato leaves to curl: Tomato Mosaic Virus (TMV) and yellow leaf curl. TMV is transmitted by contaminated tools, infected seedlings or tobacco products.

The Yellow Leaf Curl (TYLCV) is primarily transmitted by whiteflies. This sap-sucking insect feeds on an infected plant and then transmits it to healthy plants.

How to Fix This:

Use miticides labeled broad mite control or apply organic insecticidal soap. For viruses, If you are a tobacco smoker, wash your hands before attending to tomato plants to prevent Tomato Mosaic Virus.

Use canola oil and mix it with dish soap and spray your tomato plants on a weekly basis to get rid of whiteflies that transmit the Yellow Leaf Curl Virus.

05. Nutrient Imbalance

Nutrient imbalance (Nitrogen, Phosphorus, Potassium) in the soil can cause leaf curl in tamato plants. For example, if there is too much Nitrogen in the soil, your tomato plants will produce more leaves and the soil won’t have enough nutrients to sustain them thus leading to leaf curl.

How to Fix This:

Use a balanced fertilizer throughout the growing season of your tomato plants. Apply it a few times.

06. Herbicide Drift

Exposing your tomato plants to herbicides, even in small amounts, can cause leaves to curl. They are highly sensitive to herbicides. If you notice your tomato leaves curling downwards, they might be exposed to herbicide drift from nearby applications – either on your side or from a neighbor’s farm.

How to Fix This:

Unfortunately, if the herbicide drift has already occurred, there is nothing that can be done about it. Depending on how severe the damage is, the plant might or might not recover. Also, be cautious when applying herbicides around your farm – avoid applying on windy days.

07. Excess Pruning

While regular pruning helps boost fruit production in tomato plants, too much pruning at once can cause serious problems – leaf curl. Removing too much leaves at once can stress the plant, causing the remaining leaves to curl.

How to Fix This:

To help the plant recover from excessive pruning, water deeply and regularly, especially during dry periods, and avoid waterlogging. You can also use a balanced fertilizer or a well-rotted manure. The plants should recover after a few weeks.

Summing Up

Tomato plant leaves curling can be as a result of environmental stress, such as (extremely high temperatures, or strong winds), over or underwatering, nutrient imbalance, or pests and viruses. Identifying the issue at hand and applying effective solution can help restore your plant’s health.

Author Profile

Mary

🌿 Hello! I'm Mary, the nature-loving soul behind Serene Eden. Gardener, plant whisperer, compost connoisseur, sun-soaked plant enthusiast, and avid bee-watcher. Let's cultivate beauty, one bloom at a time. 🌱🌼