Do you have tomato plant leaves that are curling, yellowing, or have spots? If so, don’t worry—you’re not the only one and you’re in the right place. In this blog post, we’ll walk you through the causes of tomato plant leaf yellowing and curling and share the steps you’ll need to take in order to resolve the issue and get your tomatoes growing and thriving again.
Table of Contents
Identifying the Causes of Tomato Plant Leaf Yellowing and Curling
Unfortunately, there can be mishaps in the garden and plants may show signs of illness. To save the plant, it’s critical to be able to identify when there’s an issue. Tomato plant leaf yellowing and curling is one of those problems you may run into.
What causes this to happen though?
There are several different reasons why a tomato plant’s leaves turn yellow and curl so let’s examine them.
- Environmental stress, such as too much sodium, too much or too little water, over-fertilizing, poor drainage, inadequate sunlight
- Nutrient deficiency, such as magnesium, nitrogen, and iron
- Various tomato plant diseases, such as early and late blight, leaf curl viruses, bacterial wilt
- Shock from transplanting
[RELATED POST: Tomato Blight: What is It, What Varieties are Resistant, and How to Prevent Blight]
Environmental Stress
The most common cause of yellowing and curling tomato leaves is environmental stress. It’s extremely common for gardeners to overwater their tomato plants. Signs of too much water and too little water can be easily confused. When you think your plant is suffering from an inadequate amount of water, it could definitely be that it received too much. The surface level soil may be dry but below the surface, it may be wet. Overwatering can also occur when there’s been too much rain.
Signs of Overwatering
The following are symptoms of overwatering:
- Wilted leaves
- Yellow leaves
- Root rot
- Moldy soil
- Moldy roots
- Blossom end rot
- Splitting fruit
Signs of Underwatering
The following are symptoms of overwatering:
- Wilted leaves
- Yellow leaves
- Leaf drop
- Smaller leaves
- Loss of flowers
- Shriveling leaves
- Plant shriveling up
Too Much Sodium
Most plants are able to tolerate small amounts of sodium that naturally occur in the soil. When sodium levels exceed certain thresholds, salt damage can occur. This can be particularly damaging in soil that naturally has a low sodium content. Salt damage, also known as salt toxicity, can affect the health of the plants growing in the soil, as well as the overall fertility of the soil. Sodium can interfere with the absorption of essential minerals such as magnesium, calcium, and potassium. It also impedes the plant’s ability to uptake water. Therefore, it’s important to monitor sodium levels in your soil and take action to reduce sodium content when needed. There are several options available to help reduce the amount of sodium present in your soil, including leaching, diluting, or substituting sodium with other ions. Maintaining optimal sodium levels in your soil is essential for a healthy garden.
Symptoms of Salt Toxicity
- Wilting leaves
- Stunted growth
- Dry, discolored foliage (yellow to brown)
- Dead foliage
- Death of the plant
These symptoms usually show first on older foliage, which may prematurely die and drop.
Over-Fertilizing
Tomatoes are often referred to as ‘heavy eaters’ meaning they require quite a bit of fertilizer to be healthy and produce great tasting fruit. ‘Heavy eaters’ draw more nutrients from the soil in comparison to other plants and may require extra nutrients. In spite of being heavy eaters, it’s still possible to overfeed them.
Tomato plants need to be fed at least two times during their stages of growth – when they’re planted and when they’re about to fruit. Some say to feed tomato plants every 4 to 6 weeks.
This most important thing is – follow the instructions on the fertilizer you choose to use.
The best type of fertilizer to use is a high quality compost.
Poor Drainage
Poor drainage can cause plants to have too much water. Most plants do not like ‘wet feet’ (meaning their roots sitting in water). A plant sitting in water can lead to:
- Wilting
- Yellowing of leaves
- Decline in growth
- Death of the plant
Poor drainage can lead to an increase in plant disease because diseases thrive in moist, highly oxygenated environments. Without adequate drainage, roots can easily become waterlogged, strangled, and unable to uptake much-needed nutrients and water. Understanding the importance of drainage and how it affects the health of your plants is key to having a successful and flourishing garden.
Inadequate Sunlight
Tomato plants LOVE the sun. It’s really important that they receive a lot of sunlight for growth and to produce fruit. Having them in a garden that has a lot of shade isn’t ideal. They need at least 6 to 8 hours of full direct sun each day since they convert sunlight into energy. With that energy, the plant is able to produce fruit.
Symptoms:
Inadequate light causes chlorophyll to not work anymore, leaves darken, yellow, and fall off.
Additionally, tomato plants can be affected by diseases, such as early and late blight and leaf curl viruses. While not always the case, these viruses can be responsible for yellowing and curling leaves. To treat and prevent these issues, it’s important to ensure that the soil, watering, and fertilizing are balanced. Monitor the soil to ensure it doesn’t become too salty, and make sure the plants are receiving the necessary nutrients without overwatering.
Understanding Tomato Plant Fungal Diseases and How to Treat Them
Knowing the basics of tomato plant fungal diseases and how to treat them is essential for any avid gardener. Fungal diseases occur when fungi invade the plant, leading to damage and eventual death. Identifying the type of fungal disease is the first step in treating it, since different fungi require different treatments.
Possible Tomato Plant Fungal Diseases You May Encounter
These are just examples of fungal diseases you may encounter in the garden:
- Early blight
- Late blight
- Septoria leaf spot
[RELATED POST: Blossom End Rot: What is It and How to Prevent It?]
Tomato Plant Fungal Diseases Symptoms
Common signs of tomato plant fungal diseases include discoloration (such as yellowing of leaves), wilting, rot, irregular black or brown spots, and the presence of lesions. Upon detecting a fungal disease, it’s important to act quickly to treat the plant to prevent it from spreading to other tomatoes in the garden.
Tomato Fungal Treatments
Treatment for the tomato plant fungal disease depends on the type of disease. Common treatments for tomato plant fungal diseases include:
- Pruning infected leaves
- Improving air circulation around the plant
- Removing old plant debris
- Remove all tomato plants at the end of each growing season
- Crop rotation
- Keep leaves dry
- Plant tomatoes in full sun
- Remove any branches that touch the ground
- Stake plants to keep them off the ground
- Cover the soil with at least 6 inches of mulch – this maintains soil moisture and suppresses weeds
With the right treatment and care, tomato plants can often be saved and continue to provide delicious produce.
Natural Remedies for Tomato Plant Leaf Yellowing and Curling
Natural remedies for tomato plant leaves yellowing and curling can be found right in your own kitchen.
Garlic Tea
A garlic-based tea can be made by boiling two cloves of garlic in one quart of water. After straining, allow the tea to cool and then use this solution to water the stems and leaves of your tomato plants.
Epsom salt, Baking Soda, Water
Others swear by a mixture of four tablespoons of Epsom salts, one tablespoon of baking soda and a gallon of water applied to the soil and watered in around the plants. This can operate as a fertilizer and is a simple way to give the plants a necessary boost.
Insecticidal Soaps
Insecticidal soaps can also be used to help ward off pest attacks. Simply mix about a teaspoon of the soap in one quart of water and spray the plants with the solution.
Conclusion
The key to fixing tomato plant leaf yellowing and curling is identifying the cause and taking steps to remedy it. Fungal diseases can be treated through fungicides, and physical causes can be prevented by properly caring for your plants, such as avoiding stress, proper watering, and adequate sunlight. Additionally, leveraging natural remedies like baking soda and neem oil can help your plants get back to their healthy, vibrant selves.
If you’re struggling with tomato plant leaf yellowing and curling, don’t despair! Follow the steps in this post to diagnose and treat the issue, and get back to enjoying all the delicious fruits of your labor. Share this post with friends and family who are having the same issue and don’t forget to leave a comment below if you have any questions or additional tips.
