6 Causes of Mint Leaves Turning Brown (With Easy Fixes)

Do you frequently use fresh mint leaves in your kitchen, beverage, or medicine cabinet? Infusing a meal or drink with the refreshing flavor and fragrance of mint leaves is a simple and effective way to enhance its appeal.

But, mint leaves turning brown is one such problem which we need to deal with frequently. Frustration and worry are natural responses, particularly if you don’t know what’s causing the problem or how to solve it.

Keep your mint plants healthy and flourishing by reading this article to learn about the most common reasons for mint leaves turning brown and the steps to avoid or remedy the problem.

Whether you’re an old hand at gardening or just getting your feet wet, you’ll find what you need here. Don’t be put off by the browning of the mint leaves; instead, let’s get to work revitalizing the plants so we can all reap the benefits of mint at its peak.

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6 Common Causes of Mint Leaves Turning Brown

Mint leaves are a popular and versatile herb used in many dishes and beverages. However, brown leaves on your mint plant can cause concern.

Here are 6 common causes of mint leaves turning brown and how to prevent them.

Overwatering

Browning foliage on mint plants is usually caused by overwatering. As a result, the soil becomes saturated, and the plant roots are deprived of oxygen.

Consequently, the foliage may wilt, change yellow, and finally turn brown. Overwatering can be made worse by any already prepared soil in bad condition. Root rot and leaf browning can occur if the water stays in the soil too long or the soil doesn’t flow well enough.

Only moisten your mint plants when the soil is completely dry. Avoid overwatering by waiting for the soil to dry before adding more water. Ensure your dirt drains well by blending in sand, perlite, or vermiculite when preparing your plant.

Underwatering

Underwatering is another common cause of brown leaves on mint plants. When underwater, the soil becomes too dry, and the roots cannot absorb enough water.

As a result, the leaves can become dry and brittle, eventually turning brown. There are several causes of underwatering, including:

• Infrequent watering: The foliage of your mint plant will turn brown if you don’t moisten it enough. To avoid this, water your mint shrub frequently, particularly in the summer.
• Shallow watering: If you only water the soil’s surface, the roots may not receive enough water, leading to brown leaves. Make sure to water your mint plant deeply so the water reaches the roots.
• Small pot size: You risk underwatering and leaf browning if your pot is too tiny, as the soil will dry out too fast. Keep your mint plant happy and healthy by giving it plenty of room in its container.
• Poor soil quality: Waterlogging and leaf browning can occur if your dirt is low quality. Using a high-quality potting mix containing peat moss, vermiculite, or perlite, which all aid in water retention, can help avoid this problem.

Lack of proper drainage

A lack of proper drainage is another common cause of brown leaves on mint plants. If your pot or container does not have adequate drainage holes, excess water can accumulate in the soil, leading to waterlogged roots and brown leaves.

There are several causes of improper drainage, including:

• Improper potting mix: If your potting mix is too heavily compacted and does not have adequate drainage, excess water can accumulate in the soil, causing brown leaves. To prevent this, use a well-draining potting mix that contains sand, perlite, or vermiculite.
• Little or no drainage holes: Waterlogged roots and brown foliage indicate that the drainage holes in your pot or container are too tiny or nonexistent. Have sufficient drainage openings drilled into your pot or container.
• Clogged drainage holes: If your pot or container’s drainage holes become clogged with soil or debris, water cannot drain properly, leading to waterlogged roots and brown leaves. Make sure to check and clear the drainage holes regularly.

Pests and diseases

Pests and diseases are other common causes of brown leaves on mint plants. Some several pests and diseases can affect mint plants, including:

Pests

• Spider mites: As they feast on the plant’s juices, these microscopic pests discolor the foliage and stunt its growth. They make holes in the plant cells, letting the fluid out and killing or discoloring the cells inside.
• Aphids: Tiny, squishy insects that feed on the mint leaves and color them yellow and brown by sucking out their sap. As they sip the juices from the plant, they introduce toxins that can change the appearance of the foliage.

Diseases

• Fungal infections: In wet climates, powdery and downy mildew can produce brown spots on mint foliage. The fungi colonize the leaf surfaces, preventing the plant from receiving adequate sunshine and killing the afflicted cells.
• Bacterial infections: Overwatering, poor drainage, or damage can cause bacterial infections, leading to brown spots on leaves. The bacteria infect the plant tissue, causing necrosis (death of the cells), which leads to brown spots.
• Viral infections: Spread by insects or contaminated tools, viral infections can cause yellowing or browning of mint leaves. The virus infects the plant cells, leading to discoloration and distortion of the leaves.

These pests and diseases weaken the mint plant’s ability to photosynthesize, leading to brown leaves. The brown spots are caused by the death of the affected cells, which can result from sap loss, blockage of sunlight, or cell necrosis.

Regular monitoring and appropriate control measures are necessary to prevent and treat pest and disease infestations.

Exposure to direct sunlight

Mint plants need bright light to thrive, but intense sunshine will cause the leaves to wither and discolor if exposed for too long. High temperatures and bright lights can induce dehydration in plant foliage by damaging cell membranes.

The leaves can also get sunburned, which can cause them to turn brown and crispy. This happens when the plant is exposed to direct sunlight for too long, and the leaves cannot protect themselves from the intense heat.

Environmental factors (humidity, temperature)

Although mint plants flourish in mild, wet environments, the foliage can turn brown if the humidity or temperature is too high.

Conversely, the plant can lose hydration and become desiccated due to low humidity levels, resulting in brown and crispy foliage.

Contrarily, damp conditions are ideal for developing fungal illnesses, which can result in leaf discoloration and dark patches due to high humidity.

Extreme temperatures can also cause the leaves to turn brown. The leaves can become scorched and dry out if the temperature is too high. If the temperature is too low, the plant can become stressed and susceptible to diseases and pests.

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Prevention of Mint Leaves Turning Brown

Now that we’ve discussed the common causes of mint leaves turning brown let’s focus on prevention. You can keep your mint plant healthy and thriving with the right care and attention.

Proper watering technique

​​Watering is essential to mint plant care, and improper watering is one of the most common causes of brown leaves. It is important to follow proper watering techniques to prevent brown leaves caused by overwatering or underwatering.

How often to water mint plants

Mint plants need a steady water supply, but they don’t thrive when soggy. The temperature and surrounding conditions will determine how often you should irrigate.

Once a week during the growing season and every two weeks during the winter is the general rule of thumb for watering the shrub. On the other hand, if you touch the soil and it feels dry, you need to hydrate your plant.

How much water to give to mint plants

When watering your mint plant, it is important to avoid overwatering. Overwatering can cause the soil to become waterlogged, leading to root rot and brown leaves.

The amount of water required depends on the size of the pot, the soil composition, and the plant’s growth stage. You should generally water the plant until the soil is moist but not waterlogged.

Best practices for watering mint plants

To prevent brown leaves caused by improper watering, it is essential to follow these best practices:

• Use a well-draining soil mix to prevent water from pooling in the pot.
• Water the plant at the base, avoiding the leaves and stems.
• Use a watering can with a fine spout to control the water flow.
• Water the plant in the morning or evening when the temperatures are cooler.
• Avoid watering the plant during the hottest part of the day, as the water can evaporate quickly.

Use of well-draining soil

The right soil mix is essential for healthy mint plant growth and for preventing brown leaves. Mint plants require a well-draining soil mix to avoid waterlogging, which can lead to root rot and brown leaves.

The Importance of Well-Draining Soil for Mint Plants

Mint plants are sensitive to overwatering, and their roots can easily rot if they sit in water too long. Well-draining soil allows excess water to drain away, preventing waterlogging and keeping the roots healthy.

A soil mix that is too heavy or dense can retain too much moisture, leading to brown leaves and other problems.

How to Improve Soil Drainage for Mint Plants

Improving soil drainage is important for preventing brown leaves caused by overwatering. Here are some ways to improve soil drainage:

• Add perlite or coarse sand to the soil mix to increase drainage.
• Mix organic matter like compost or aged manure to improve soil structure and drainage.
• Use a pot with drainage holes to allow excess water to drain away from the roots.
• Avoid using heavy garden soil or clay-based soils, which can retain too much moisture.

Avoiding overcrowding

Mint plants are fast growers and can quickly spread to take over a garden bed. While it may be tempting to plant several mint plants close together, overcrowding can lead to brown leaves and other problems.

Effects of Overcrowding on Mint Plants

When mint plants are overcrowded, they compete for water, nutrients, and sunlight. This can cause plant stress, leading to brown leaves, stunted growth, and an increased risk of pests and diseases.

How to Space Out Mint Plants

To avoid overcrowding and prevent brown leaves, space out your mint plants according to their variety and growth habits. Here are some general guidelines:

• Plant mint plants at least 18 inches apart to allow for proper airflow and to prevent overcrowding.
• Consider using containers to grow mint plants if you have limited space. Use a container at least 12 inches in diameter to give the plants enough room to grow.
• Trim back the mint plant regularly to prevent it from becoming too large and overcrowded.

Monitoring for pests and diseases

Pests and diseases can quickly take hold of a mint plant, causing brown leaves and other problems. Regular monitoring is key to catching these issues early and preventing them from spreading.

Importance of Regular Monitoring for Pests and Diseases

By regularly monitoring your mint plants for pests and diseases, you can catch any issues early before they become a major problem. Look for any signs of damage or infestation, such as brown leaves, yellowing, wilting, or unusual growth patterns.

You can also use sticky traps or pheromone traps to help detect any insect pests that may be present in your garden. These traps can be hung near your mint plants, attracting and trapping any flying pests.

Another helpful tool for monitoring is a magnifying glass or hand lens. This can help you inspect your plants more closely and identify any small pests that may be present, such as spider mites or aphids. 

How to Prevent Pest and Disease Infestations

Prevention is key when it comes to pests and diseases. Here are some tips to help prevent these issues from affecting your mint plants:

• Use companion planting: Planting other plants nearby that repel pests, such as marigolds or garlic, can help deter pests from your mint plants.
• Keep your garden clean: Remove debris or dead plant matter from your garden bed to reduce the risk of pests and diseases.
• Use organic pest control methods: Natural pest control methods like neem oil or insecticidal soap can effectively control pests without harming beneficial insects or the environment.
• Practice crop rotation: Planting mint in the same spot year after year can increase the risk of pest and disease infestations. Rotate your crops every few years to help prevent these issues.

Providing proper shade and ventilation

The importance of shade and ventilation for mint plants cannot be overstated. Mint plants prefer cooler temperatures and do best when not exposed to direct sunlight for long periods.

Additionally, mint plants need good air circulation to prevent fungal diseases and to keep the leaves from becoming too moist.

To provide shade and ventilation for mint plants, consider planting them in a location that receives partial shade or in a shaded spot during the hottest parts of the day.

You can also use shade cloth or other types of temporary shading to help protect your plants from direct sunlight. Alternatively, if they are planted in containers, you can simply move them around where they can receive shade when necessary. 

For ventilation, ensure your mint plants are not overcrowded and have enough space between them to allow for good air circulation. You can also use a small fan or create windbreaks to help promote airflow.

Maintaining appropriate humidity and temperature

​​Mint plants thrive in a specific range of humidity and temperature. The ideal humidity for mint plants is 40-60%, and the ideal temperature range is between 60-70°F (15-21°C).

These conditions mimic the natural environment in which mint plants are typically found, and they help ensure the leaves stay healthy and green.

To maintain appropriate humidity and temperature for mint plants, consider using a humidifier or a small water tray to increase humidity levels around the plants. You can also mist the leaves with water regularly to provide extra moisture.

For temperature control, ensure your mint plants are not exposed to extreme temperatures, such as those found near windows or doors. You can also use a thermometer to monitor the temperature around your plants and adjust as needed.

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Treatment of Mint Leaves Turning Brown

If you’ve noticed brown leaves on your mint plant, don’t worry – several treatment options are available to help revive your plant and restore it to its former healthy state.

In this section, we’ll explore some effective treatments for brown mint leaves and how to implement them to bring your mint plant back to life.

Pruning affected leaves

Pruning affected leaves is a simple and effective way to treat brown mint leaves. Here is a step-by-step guide on identifying and pruning the affected leaves accordingly: 

1. Identify the affected leaves: Brown and crispy leaves are a clear sign of damage or disease. These leaves will feel dry and brittle to the touch.
2. Isolate the plant: Once you have identified the affected leaves, it’s important to isolate the plant to prevent the spread of the disease. Remove any dead leaves or stems from the plant.
3. Sterilize your pruning shears: To prevent the spread of disease, sterilize your pruning shears by wiping them with rubbing alcohol.
4. Cut off affected leaves: Using the sterilized pruning shears cut off the affected leaves and cut close to the stem. If the stem is also affected, cut it back to promote healthy growth.
5. Dispose of the affected leaves: Once you have removed them, dispose of them in a sealed bag to prevent the spread of disease.
6. Monitor the plant: Keep a close eye on the plant to ensure the disease does not return. If it does, repeat the process.

Use of natural remedies

Natural remedies can be a great way to treat brown mint leaves while avoiding harsh chemicals. Natural remedies can help prevent the spread of pests and diseases and promote healthy growth.

Some benefits of using natural remedies include

• They are non-toxic and safe for the environment.
• They can be made at home with common household items.
• They can be effective in treating a variety of pests and diseases.

Here are three natural remedies that can be used to treat brown mint leaves

1. Neem oil: Neem oil is a natural insecticide that can treat various pests, including spider mites and aphids. Mix one tablespoon of neem oil with one quart of water and a few drops of dish soap to make a neem oil spray. Spray the solution on the affected leaves, covering both the tops and bottoms.
2. Garlic spray: Garlic has natural antifungal properties and can treat fungal infections on mint leaves. To make a garlic spray, blend a few cloves of garlic with one quart of water and strain the solids. Spray the solution on the affected leaves, covering both the tops and bottoms.
3. Soap spray: A simple soap spray can be effective in treating a variety of pests, including spider mites and aphids. Mix one tablespoon of liquid dish soap with one quart of water to make a soap spray. Spray the solution on the affected leaves, covering both the tops and bottoms.

Fertilizing with nitrogen-rich fertilizer

Fertilizing is essential for any plant, and mint is no exception. Nitrogen is one of the essential nutrients that plants need to thrive, and it is crucial for the growth and health of mint.

Nitrogen is responsible for producing chlorophyll, which gives plants green color and helps them convert sunlight into energy through photosynthesis.

To fertilize mint plants with a nitrogen-rich fertilizer, choose a high-quality fertilizer with a balanced N-P-K ratio. N, P, K (nitrogen, phosphorus, potassium). The ratio of these three elements should be balanced, with nitrogen being the most abundant. A good ratio for mint plants is 3-1-2.

It’s best to fertilize mint plants in the spring when they begin to grow actively. You can apply the fertilizer around the plant’s base, ensuring not to get on the leaves. Water the plant well after fertilizing to help absorb nutrients into the soil.

It’s important not to over-fertilize mint plants, as this can lead to excess nitrogen and cause the leaves to turn brown. Be sure to follow the instructions on the fertilizer package and use it sparingly.

Re-potting in fresh soil

When it comes to re-potting mint plants, timing is key. It’s recommended to do this every 1-2 years or when the plant starts to outgrow its container. Signs that it’s time to re-pot include roots growing through the drainage holes or when the soil is depleted and can no longer retain water.

Here is a step-by-step process for re-potting your mint plant:

1. Select a pot at least 2 inches larger than the current container and has good drainage.
2. Gently remove the mint plant from its current pot, carefully not damaging the roots.
3. Loosen any tangled or tightly packed roots.
4. Fill the new pot with fresh potting soil, leaving enough space at the top for the mint plant.
5. Place the mint plant in the new pot, ensuring the top of the root ball is level with the top of the soil.
6. Fill any remaining space with potting soil and gently press down around the plant.
7. Water the plant thoroughly and place it in a shaded area for a few days to help it recover from the shock of being repotted.

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Pro Tips for Maintaining Healthy Mint Plants

Now that we’ve covered the common causes, prevention, and treatment of brown mint leaves, let’s look at some pro tips for keeping your mint plants healthy and thriving.

These tips will help you avoid brown leaves and promote robust growth, high yields, and delicious flavor.

Regular monitoring for pests and diseases

Regular monitoring of pests and diseases is essential for maintaining healthy mint plants. It is recommended to check mint plants once a week for any signs of pests or diseases.

Early detection and treatment of any issues can prevent the spread of infestations and save the plant from further damage. Signs to look out for include discoloration, wilting, and unusual growth patterns.

Proper identification of the pest or disease is crucial for effective treatment, and natural remedies or pesticides may be used depending on the severity of the infestation.

Regular monitoring and prompt treatment can ensure the longevity and health of mint plants.

Pruning regularly to encourage growth

Mint plants benefit from regular trimming to promote healthy development. It encourages the growth of new stalks and foliage by removing the old ones and removing those that are damaged or deceased.

Keeping the plant pruned will keep it from getting too bushy and inviting unwanted bugs and illnesses. Trim the stalks and foliage of your mint plants with a pair of clippers or pruning shears.

Cut back the plant by about a third at a time, paying special attention to the excessive or injured parts. Heavy trimming, such as hacking the plant back to the ground, can shock it, stunting its development.

Harvesting leaves regularly

Regular harvesting of mint leaves is essential to ensure optimal growth and flavor. The best time to harvest is when the leaves are young and tender. It is recommended to pick off the top 1/3 of the plant’s growth, leaving the remaining leaves to continue growing.

Mint leaves can be harvested every two to three weeks during the growing season. Frequent harvesting promotes new growth and prevents the plant from becoming too woody. When harvesting, gently pinch off the leaves at the stem, careful not to damage the plant.

Using organic fertilizers

Using organic fertilizers for mint plants has many benefits, including promoting soil health and preventing chemical buildup. Organic fertilizers release nutrients slowly and steadily, providing a constant source of nutrition for your mint plant.

To choose an organic fertilizer, look for one high in nitrogen and contains natural ingredients such as compost, bone meal, or fish emulsion.

Apply the fertilizer according to the package instructions, taking care not to over-fertilize as this can lead to burnt leaves and other issues. Regularly using organic fertilizers can help maintain the health and productivity of your mint plant.

Using companion planting to deter pests

Companion planting is the practice of growing different plants together to benefit each other. It can also be used to deter pests from mint plants. For example, planting garlic or onions near mint can repel aphids and spider mites. Planting marigolds or petunias can attract beneficial insects that prey on pests.

You can also plant herbs like basil or chamomile near the mint, which can improve the flavor and quality of the mint. By incorporating companion planting into your gardening practices, you can help keep your mint plants healthy and pest-free without harsh chemicals.

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Frequently Asked Questions (FAQs)

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Conclusion:

In conclusion, brown mint leaves can be caused by various factors such as overwatering, underwatering, poor soil drainage, pests, diseases, direct sunlight, and environmental factors. Prevention includes:

• Proper watering techniques.
• Use of well-draining soil.
• Regular monitoring for pests and diseases.
• Providing proper shade and ventilation.
• Maintaining appropriate humidity and temperature.

Treatment includes pruning affected leaves and using natural remedies. Remember to maintain healthy mint plants by regularly monitoring for pests and diseases, pruning regularly, harvesting leaves, using organic fertilizers, and companion planting.

We hope that this guide on mint leaves turning brown has been helpful. You can read about similar topics here on our website. Check back again soon for more.