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There are many things that can cause tomato plants to turn brown, such as environmental stress, insect infestations, nutrient deficiencies, bacterial and fungal diseases, and physical problems.
To keep tomato plants from getting brown spots, it’s important to keep them well-watered and fed, protect them from pests and diseases, and keep an eye out for signs of stress or damage.
If you are seeing brown leaves on your tomato plants, you don’t need to worry. In the years I have spent growing these garden favorites, I have witnessed hundreds of tomato leaves fade from green to a sad brown color.
Join me as I’m going to explain the causes of tomato plant browning and how to prevent it in this article.
Reasons Your Tomato leaves Are Turning Brown
If your tomato plant’s leaves are turning brown, there could be a few different reasons for this. Brown leaves on tomato plants can also be a sign of disease, such as early blight or late blight. These pests feed on the leaves and can cause them to turn brown and dry out.
These fungal diseases can cause brown spots to appear on the leaves and eventually cause the entire plant to wilt and die. To prevent the spread of disease, it’s important to remove any affected leaves and avoid overhead watering.
The first step to fixing the problem and making your tomato plant healthy again is to figure out what caused it. There are several reasons your tomato plants’ leaves are turning brown. They are given below;
1. Over and Under Watering
Watering improperly is the main cause of brown leaves on tomato plants. They have negative effects on tomato plants. Overwatering can lead to root rot and other fungal diseases, while underwatering can cause the plant to wilt and stunt its growth.
The gardeners also go wrong sometimes in watering the plants, sometimes by providing the plant with too much water and sometimes with too little. In order to keep plants healthy, gardeners need to take extra care of tomato plants.
The excess water in the soil can suffocate the roots and rot them. As a result of the reduced availability of oxygen to the leaves, the roots suffer. It causes them to turn brown and fall off.
Fixation
Correct watering is essential for tomato plants. Check soil daily and water the plants in the morning according to their need to prevent evaporation or damage of leaves. To prevent underwatering, it is important to water the plants deeply and consistently, making sure that the soil is moist but not waterlogged.
2. Bad Companion Plants
Yes, bad companion plants can have a negative impact on tomato plants and their growth. Some plants are known to release chemicals that can inhibit the growth of other plants or attract pests that can damage tomato plants.
For example, plants from the Brassica family can release compounds that can stunt the growth of tomato plants. In the same way, plants that are more likely to get diseases or pests can spread them to nearby tomato plants.
Fixation
To ensure the healthy growth and productivity of tomato plants, it is important to choose companion plants that are compatible and beneficial. Herbs like basil and marigolds are good companion plants for tomatoes because they can keep pests away and attract good bugs.
3. Excessive Heat and Sunlight
Heat and sunlight can affect tomato plant leaves and their ability to carry out photosynthesis, which is the process by which they fix carbon dioxide into sugars and other organic compounds. Tomato plants are adapted to grow in warm temperatures, but excessive heat can cause stress and damage to the leaves.
When temperatures are too high, the plant may close its stomata to conserve water, which can reduce the amount of carbon dioxide available for photosynthesis. High temperatures can also cause the plant’s enzymes to become less efficient, further reducing its ability to fix carbon.
Excessive sunlight can also be damaging to tomato leaves. When exposed to intense light for prolonged periods, the leaves may become scorched or burned. This can damage the chlorophyll in the leaves, reducing the plant’s ability to carry out photosynthesis.
Fixation
Tomato plants require at least 6–8 hours of sunlight per day for optimal growth and development. So while too much heat and sunlight can be harmful, a moderate amount is necessary for healthy tomato plants.
4. Spider Mites
Spider mites are tiny pests that belong to the arachnid family. They are known to cause various diseases in plants, including tomatoes. One common symptom of spider mite infestation on tomato plants is the development of brown or yellow spots on the leaves.
Spider mite infestations can also cause the leaves of tomato plants to become fixed or inflexible, making them appear rigid and brittle. This happens because spider mites feed on the cells within the leaves, which can cause the plant to lose its elasticity.
Fixation
Spider mites can do a lot of damage to tomato plants if they are not treated. This can lead to stunted growth, less fruit, or even death of the plant. Therefore, it is essential to take measures to prevent and control spider mites on tomato plants.
Read More:
- All You Need To Know About Tomatoes.
- How Big Of A Pot For Tomatoes? Ideal Container Size For Tomato Plants
- Hybrid or Heirloom Tomatoes? Which of These Two Types Is better?
5. Bacterial Leaf Spots
Bacterial leaf disease is a plant disease caused by the infection of bacteria on tomato plant leaves. The bacteria responsible for this disease can vary depending on the region and conditions.
Brown or black spots on the leaves of tomato plants are a sign that they have bacterial leaf disease. These spots may have a yellow halo around them and can cause the leaves to wilt and die.
The disease can damage the leaves and reduce the plant’s ability to produce energy through photosynthesis, which can decrease yield.
Fixation
Bacteria can be kept from spreading through cultural practices like planting varieties that are resistant to disease, making sure there is enough water and drainage, and not watering from above. Chemical ways to stop the disease, like using fungicides or bactericides with copper, can also help.
6. Early Blight and Late Blight
Early blight and late blight are two common diseases that affect tomato plants and are caused by different fungal pathogens.
Early blight appears as small, dark lesions on the lower leaves of tomato plants. These lesions often have a concentric ring pattern and may expand over time, causing the leaves to turn brown and eventually die. Early blight can make it hard for tomatoes to grow, but it usually doesn’t kill the plant.
Late blight is a more severe disease that can kill tomato plants quickly. It typically appears as a water-soaked lesion on the leaves, which quickly turns brown and spreads to the stem and fruit. Late blight can spread rapidly in wet and humid conditions, making it a significant threat to tomato crops. In severe cases, entire fields of tomato plants can be wiped out by the disease.
Fixation
Both early blight and late blight can be managed through crop rotation, sanitation, and using disease-resistant tomato varieties. Fungicides can also be used to prevent or control diseases. It is important to check tomato plants often for signs of disease and act quickly to stop the infection from spreading.
7. Transplant Shock
Plants get transplant shock when they are moved from one place to another and experience stress because of it. This can happen when tomato seedlings are transplanted from a seed tray or pot to a garden bed.
During transplant shock, the tomato plant may wilt, its leaves may turn yellow, its growth may be stunted, and the leaves or stems may even turn brown. This is because the plant is not able to adjust to the new environment quickly.
The shock can cause the bottom few leaves of the plant to turn brown. This is a short phase, but with the passage of time, when new leaves grow, they automatically turn green and healthy.
Fixation
Water the plants well before transplanting. It is best to transplant tomato seedlings when they are about 6–8 weeks old and have at least two true leaves. Transplant in the evening or on a cloudy day.
About a week before transplanting, gradually expose the tomato seedlings to wind and sun to help them get used to the new environment. Use a transplant fertilizer. Due to this, the brown leaves will drop off by themselves and the plant will become in good condition.
8. Verticillium Wilt
Verticillium wilt is a fungal disease that affects many plants, including tomato plants. Verticillium wilt starts when the lower leaves of tomato plants turn yellow and fall off.
The disease then progresses up the plant, causing the leaves to turn brown and die. Infected plants often have stunted growth and produce fewer and smaller fruits than healthy plants. In addition to affecting the leaves and fruit of tomato plants, Verticillium wilt can also impact the plant’s ability to fix nitrogen.
Nitrogen fixation is the process by which certain plants, including tomatoes, convert atmospheric nitrogen into a form that can be used by the plant. But Verticillium wilt can make it harder for the plant to fix nitrogen, which can lead to more problems with growth.
Fixation
Verticillium wilt can’t be cured, so infected plants should be pulled out and killed to stop the disease from spreading to other plants. Crop rotation, using varieties that are resistant to disease, and keeping the soil healthy can all help stop the disease from spreading in the first place.
9. Canker
Bacterial canker of tomatoes
Canker disease is a bacterial disease that affects tomato plants, causing the leaves to turn brown and die. The bacteria that cause the disease can get into the plant and move through its vascular system.
The first symptoms of canker disease on tomato plants are small, circular, brown lesions on the leaves, stems, and fruit. As the disease gets worse, the spots can get bigger and more numerous, and the leaves can eventually turn brown and die. Infected plants may also have stunted growth and produce fewer fruits than healthy plants.
Fixation
Unfortunately, there is no cure for canker disease, and infected plants should be removed and destroyed to prevent the spread of the disease to other plants. To stop the bacteria from spreading, it is also important to clean any tools or equipment that comes into contact with sick plants.
10. Blossom End Rot
Blossom end rot is a disorder that affects the fruit of tomato plants, not the leaves.
A calcium deficiency in the developing fruit can result in blossom end rot, which can cause the blossom end to turn brown and become flattened. It can be caused by irregular watering or soil that is too acidic.
Fixation
To keep tomatoes from getting blossom end rot, it’s important to give the plant enough calcium. This can be done by maintaining consistent moisture levels in the soil.
If you are seeing brown spots or discoloration on the leaves of your tomato plant, this could be a sign of a different issue, such as a fungal disease, nutrient deficiency, or pest infestation.
Read More:
- Will Tomato Plants Regrow Every Year?
- Why Tomato Leaves are Beneficial for Your Garden? (5 Solid Reasons)
- White spots on tomato leaves: their causes and fixes
Conclusion
Certain physiological disorders, such as internal browning, can cause tomato fruit to turn brown. These disorders are often caused by uneven watering, high temperatures, or nutrient imbalances.
Tomato plants need a variety of nutrients to thrive, including nitrogen, phosphorus, and potassium. A lack of these nutrients can cause the leaves to turn brown and the fruit to ripen poorly.
If brown spots do appear, it’s important to diagnose the cause and take appropriate action to address it. With proper care and attention, tomato plants can produce healthy fruit that is free from browning.
Thanks for reading!
