Why Are The Leaves On My Tomato Plants Turning Brown?

  • Date: June 22, 2022
  • Time to read: 10 min.

Growing tomato plants can be a very rewarding activity. What could be better than being rewarded for all of your hard work with super delicious, bright red, juicy tomatoes? 

However, tomato plants do tend to require a lot of attention. It is important that you keep an eye on your tomato plants for any tell-tale signs of health conditions.

Why Are The Leaves On My Tomato Plants Turning Brown?
Why Are The Leaves On My Tomato Plants Turning Brown?

The most common indicator that something is wrong with your tomato plants is browning leaves. If you notice your plant’s leaves beginning to brown, it is important to find the cause. 

Once you are able to diagnose the problem, you should soon be able to return your tomato plants to full health and ensure a great yield when the time comes. 

To learn why the leaves of your tomato plants are browning, check out some of the most common causes below. We also discuss solutions to each issue, so you can fix it ASAP!

Common Causes Of Browning Leaves On Tomato Plants

There are a number of things that may cause the leaves of your tomato plant to brown.

We’ve listed the most common causes below so that you can diagnose and solve the problem that your tomato plant is experiencing. 


First of all, one of the most common causes of browning leaves of a tomato plant is underwatering.

If the leaves of your tomato plant look crispy and are beginning to brown on the edges, it is likely that you aren’t giving it enough water. 

Tomato plants are quite thirsty plants. Whilst you should never drench them in water, they do need to be watered frequently.

It is also important that, when you do water your plants, the water penetrates deeply into the soil. 

If you notice that your tomato plant is suffering from a lack of water, it is important that you try to fix the problem as soon as possible. If your plant is continually underwatered, the leaves may wilt and experience defoliation. 

Additionally, underwatering your tomato plant can affect the quality of the yield. If the plant fruits, it is likely that the tomatoes you receive will be particularly hard and/or dry.

Underwatering can even result in blossom drop, which means that the plant won’t fruit at all.

Solution To Underwatering 

Whilst the solution to underwatering may seem pretty simple, it is important that you water your plants correctly, rather than just drenching them.

Tomato plants thrive when they are watered deeply, slowly, and at frequent intervals. 

You may have heard that watering your tomato plant in this way is important as the plant develops. Whilst this is true, it is necessary to continue watering your plant in this way, even if it looks super strong and healthy. 

We recommend that you water the soil of your tomato plants in the morning. This ensures minimal splashing (which spreads disease), and minimal evaporation.

Additionally, you should never water your tomato plants when the soil is still wet. 

Spider Mites

Whether you’re a keen gardener or a total newbie, you’ve likely been warned about spider mites.

They are very common pests that work quickly to harm your tomato plants. If you notice tiny brown specks on your tomato plant’s leaves, the plant may have spider mites. 

You may also be able to detect spider mites if you notice particularly thin webbing around your tomato plants.

These pests tend to take hold of the underside of the leaves and suck the sap from them. 

Consequently, little brown spots are visible on the leaves. The leaves often become very dry, and will eventually die.

Unfortunately, spider mites can work very quickly to rid the plant of all of its leaves, causing the plant to die. 

Solution To Spider Mites

Spider mites are very common in dry and hot environments. To ensure that these pests don’t settle on your plants, the best thing you can do is control the environment in which they live.

Specifically, it is important that you use the correct water methods so the plant is moist. 

Additionally, you may also be interested in introducing good parasitic pests to your garden so that you can control and prevent spider mite outbreaks. However, these are preventative measures only. 

If spider mites have already taken control of your tomato plant, there are several things you can do to clear these pests before they cause too much damage to your garden.

First of all, you could use a horticultural spray such as Neem Oil.

Neem Oil is an excellent insect repellent for plants. It is also very versatile and can help to prevent diseases from taking hold of your tomato plants.

However, if Neem Oil doesn’t appeal to you, you could instead opt for an insecticidal soap

Why Are The Leaves On My Tomato Plants Turning Brown?s
Why Are The Leaves On My Tomato Plants Turning Brown?

Bacterial Leaf Spot 

If you notice that your tomato plant has developed round, brown, damp spots on its leaves, it is likely that it is suffering from a disease called bacterial leaf spot.

This is a very common disease that can spread very quickly to other parts of the plant, including the stems.

If you notice the telltale signs of bacterial leaf spot, it is important that you act right away. Unfortunately, this disease can not only do immense harm to your tomato plants, but it can spread to the rest of your garden. 

If the disease has progressed, you may notice that brown spots are taking over many of your plants.

It may be that even the fruits of your plants now have small brown dots on their skin. It can also cause the leaves of your plants to discolor and fall. 

Solution To Bacterial Leaf Spot

Unfortunately, we have to be the bearer of bad news. A tomato plant that has been infected with this disease cannot be revived.

In fact, if you notice Bacterial Leaf Spot on any of your plants, you should dispose of them as quickly as possible to prevent more infections. 

When it comes to Bacterial Leaf Spot, prevention is paramount. Luckily, preventing this disease is actually quite simple.

First of all, you should always check for signs of disease in your seeds before planting them. 

For example, if you spot any fungal growth on your seeds, you should not plant them. You should also carry out the correct watering processes.

For instance, avoid watering your plant from overhead, as the splashing results in the spreading of many diseases. 

Finally, to ensure minimal risk of many dangerous diseases, we recommend sterilizing your gardening tools before using them. You should also clean them in between each plant. This is good garden hygiene practice. 

Early Blight 

If you notice that your tomato plant has developed small, light brown spots on its leaves, it is likely that Early Blight has begun to take hold.

This disease is caused by a fungus that spreads through the air. However, it does infect plants slowly. 

It can sometimes be tricky to determine whether your plant has Early Blight or Bacterial Leaf Spot because, in the early stages, they look very similar. However, they are very different diseases and should be treated as such. 

As the disease progresses, the spots associated with Early Blight will become larger and darker. They may also develop a yellow outer ring. If left untreated for too long, the leaves will die, and the stem and fruits may also become infected. 

Solution To Early Blight

Fortunately, there are a few things you can do to rid your tomato plant of Early Blight. In fact, as long as it is caught in time, Early Blight is easily preventable.

To make sure that you spot it early enough, we recommend checking your tomato plants for signs of disease daily.

If, when doing so, you notice Early Blight spots, it is necessary that you cut the infected leaves straight away.

Then, we recommend applying a fungicide that is copper-based to your plants to ensure that any lingering infection is gone. 

These measures should free your tomato plants from Early Blight. However, it is worth mentioning that preventative measures are always more effective.

To ensure that Early Blight doesn’t have the opportunity to take hold, there are a few things you can do. 

For example, you can practice crop rotation, which may prevent the fungus from clinging to your plants.

You should also always follow the proper watering processes, and ensure that all of your gardening tools are sterilized before use and in between each plant. 

Late Blight 

Late Blight 
Why Are The Leaves On My Tomato Plants Turning Brown?

Even though they have similar names and symptoms, it is necessary to understand that Late Blight and Early Blight are totally distinct fungal diseases.

Late Blight is a lot rarer than Early Blight, but it is worth knowing about because it can take hold fast. 

If you notice that your tomato plant has gone from appearing healthy to developing a range of spots in the space of just a few days, it may be that it is suffering from Late Blight.

The spots begin as a light green color, but they transform into a dark brown color very quickly. 

If the disease progresses, the spots will soon become black. In especially moist and humid conditions, this disease may also result in the growth of white mold on leaves, particularly on the undersides. 

If your plant has become infected with Late Blight, you may also notice dark brown spots on the stem and on the tomatoes.

Due to its fast-spreading nature, Late Blight can actually kill entire stems or vines in no time at all. 

Solution To Late Blight 

Unlike Early Blight, there is no way to save your plant from Late Blight if the disease has already taken hold.

If you notice that your plant has been infected with Late Blight, you will need to dispose of it as soon as possible. 

Like all diseases and infestations, preventative measures are key with Late Blight.

Just as in the case of Early Blight, to prevent Late Blight you should practice excellent garden hygiene, and crop rotation, and ensure that you are watering your plants appropriately. 


If you notice that the leaves of your tomato plant have developed crispy and brown edges, with large brown patches elsewhere, then it is likely that your plant is suffering from a bacterial disease called Canker. 

Unfortunately, Canker is known to kill plants very quickly. Generally, as the disease progresses, yellow stripes appear on the plant and the leaves eventually die and fall to the ground. The stems may also appear discolored and very dry. 

You may even notice signs of a Canker infection on the tomatoes themselves. If the plant becomes infected, the tomatoes may have small brown raised spots on their skin that are raised.

They often begin as white spots but become darker over time. 

Solution To Canker 

If your plant has been infected with Canker, unfortunately, it cannot be cured. You will need to uproot the plant that has been infected and dispose of it carefully.

It is also important that you monitor the health of your other plants to ensure that the Canker hasn’t spread. 

As with all of the diseases mentioned above, preventative measures are very effective.

In addition to the preventative measures already mentioned, mulching is also known to be very helpful in preventing Canker. 

Verticillium Wilt

This is a particularly dangerous disease that should not be taken lightly. In fact, this disease can kill many different types of plants, including trees!

Verticillium Wilt affects different plants in different ways, but when it infects tomato plants, it turns the leaves and stems brown.

Generally, this disease will initially target older leaves that are closer to the ground. It will turn such leaves yellow.

As such, it can be quite tricky to spot, because this is a process that can happen for a number of reasons. 

However, as the disease develops, the leaves affected tend to develop very large brown spots before dying and falling from the plant completely.

Verticillium Wilt can also affect the stems of the plant. They will develop brown strips if this is the case. 

It is very important that this disease is spotted early. As previously mentioned, it can affect a huge variety of plants, and it has devastating consequences.

As such, it is very important to check your plants regularly for this disease. 

Solutions To Verticillium Wilt 

There is no cure for a plant that has been infected by Verticillium Wilt. As soon as you are sure that this disease has taken hold, you need to uproot the affected plants and destroy them immediately. 

You should also keep a close eye on the rest of your garden to ensure that it hasn’t spread to any other plants.

As always, preventative measures are key in this case. We recommend purchasing plants that are Verticillium Wilt-resistant.

For instance, you could plant conifers or grasses in your garden as these are generally considered to be immune to this disease.

In turn, this works to reduce the risk of your beloved garden developing Verticillium Wilt. 


We hope that this article has helped you to diagnose your tomato plant and to find an appropriate solution. Happy gardening! 

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