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Why Are My Mint Leaves Turning Yellow? | 7 Real Causes!

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Mint is a world-famous plant. It is versatile, can thrive in strict growing conditions, and brings exquisite freshness to your vegetable or flower garden.

All these advantages make mint one of the most popular plants for a home garden.

Moreover, the fragrant aroma and the bright green color of the mint leaves bring tranquility to your home.

Even though it is not hard to grow mint in your backyard, you can occasionally run into some issues. If you are wondering why are my mint leaves turning yellow, this article is just for you!

The mint leaves could be turning yellow due to several reasons related to environmental stress or others.

If you have been facing this issue, keep reading to find the answers and solutions to your problem.

Let’s begin!

Bottom leaves on mint plant are yellowing—why are my mint leaves turning yellow?
Why are my mint leaves turning yellow? – Image via Reddit.

Why Are My Mint Leaves Turning Yellow?

Why are my mint leaves turning yellow, you say?

There are a few reasons for the yellowing of mint leaves.

  • Most of the time, the yellowing of the leaves is due to improper environmental conditions.
  • You must fulfill certain requirements to ensure optimal plant growth, such as adequate watering, lighting, fertilizer, etc.
  • The yellowing leaves could also be a sign of pest attack and diseases.
  • Depending on the situation, each stressor will have to be dealt with differently to ensure the plant’s safety.

Let’s find out some of the causes of yellowing mint leaves and what you can do about them.

1. Overwatering and Underwatering

Not giving the mint plant the correct amount of water can lead to yellowing leaves.

Issues with the watering can go both ways. You may add excessive water to the plant or not have enough water.

Overwatering leads to the blockage of oxygen for roots and, subsequently, for the plant. The plants not only breathe through leaves but also the roots.

When the soil gets blocked due to water accumulation, the oxygen and nutrients cannot pass into the roots, causing the yellowing of mint leaves.

The damage done by overwatering may be more or less severe depending on the soil structure and the duration for which you have been adding too much water. For example, clayey soil tends to hold water for an extended period, so treating that kind of soil will be more challenging.

Related article: Why Is My Mint Plant Dying?

If you see your mint leaves turning yellow and suspect that you have overwatered, you can take a few steps to combat the situation.

First, make sure that the drainage system of the planter is good. If there is no place for the water to drain out or the drainage holes are blocked, it will lead to waterlogging. So, make sure the plant pot is well-drained. It doesn’t matter if you are panting in a pot or the ground; use soil that drains well.

Underwatering happens when you don’t give enough water to the plant.

Mint needs ample water!

The optimal amount of water is between one to two times a week. However, if you neglect your plant’s watering needs, the mint leaves can change color due to lack of water.

To prevent issues with watering, make a regular watering schedule for your mint plants.

2. Not Enough Sunlight

The mint leaves will also turn yellow if you do not provide enough sunlight to the plant.

Green parts of the plant, such as leaves, have a green pigment in them called chlorophyll.

Chlorophyll helps in preparing food through the process of photosynthesis. Photosynthetic processes need sunlight; if there is insufficient sunlight, the leaves will not be able to carry out photosynthesis, and the chlorophyll will start to diminish.

So, the lack of sunlight leads to the disintegration of the green pigment, which leads to the mint leaves turning yellow.

The solution to this is to ensure that the location of your plant is such that it receives adequate sunlight throughout the day.

Please place it in a room near the window where it gets bright sunlight for at least a few hours during the day.

3. Scorching Heat

While not getting enough sunlight can cause issues for the mint plant, getting too much sunlight can also be terrible.

If you keep the mint out in direct sunlight for too long, the heat will likely burn the plant and turn the leaves yellow, white, or brown.

You must ensure that the mint plant is placed in a shady area if you have planted it outside. Avoid putting it in places where the sunlight is too bright and direct.

Medium sunlight with indirect heat is the way to go.

To add a layer of protection from excessive heat, you can put a shading cloth over the roots or plant it indoors to keep the scorching light away.

Mint plant near a window—why are my mint leaves turning yellow?
Why are my mint leaves turning yellow? Keep your plant in an area with indirect sunlight to prevent exposure to direct scorching heat—Image via Eleanor Chen.

4. Nutrient Deficiency in the Plant

The mint plant needs the right balance of nutrients to grow in the best shape.

If the plant is deficient in one or more of the nutrients, it can lead to the yellowing of leaves.

Nitrogen is one of the most common nutrients found to be lacking in the mint leaves leading to the change of color of mint leaves.

The difference in the discoloration pattern of the mint leaves tells a story about the potential cause of yellowing and which nutrients could be causing it.

  • If the entire leaf is yellow, the mint leaves are deficient in nitrogen.
  • If the edges and the sides of the mint leaves are yellow, the plant is likely deficient in potassium.
  • In case of a lack of magnesium in the plant, you will notice the veins of the mint leaves turning yellow.

If you suspect a deficiency of nutrients in the plant, you should consider adding fertilizer rich in those nutrients, i.e. if there is a lack of nitrogen, add a fertilizer that is high in nitrogen content.

The best time to add fertilizer to the plant is right before the growing season, which is spring and summer.

But be careful not to add too much fertilizer to the roots as it too can lead to yellowing and browning of the leaves.

5. Lack of Humidity

The yellowing of the mint leaves could also be due to a lack of humidity in the air.

Mint leaves do not grow well in a dry environment, so you must ensure the environment has enough moisture.

The dryness in the air is especially prominent during the winter season, so you should be extra careful in the winter to provide optimum humidity levels to the mint plant to keep it healthy.

If there is not enough moisture in the air, the plant can become dehydrated, shrivel, turn brown or yellow, and slowly the plant will die.

If you live in a particularly dry area, invest in a humidifier to keep the indoor environment comfortable for the plant. If you can sit in the room comfortably, it is the right balance for your mint plant.

6. Aphid Attack

Aphid infestation can cause the yellowing of leaves in the mint plant.

Aphids feed on the sap inside the leaves and suck the juices out of the leaves. The common indications of an aphid attack include the yellowing of leaves, the crinkling of leaves, and deformation.

To prevent the aphids from taking over, apply suitable insecticides.

Use a mixture of chemical insecticides and organic ones. You can also wash off the leaves with a DIY soap solution.

Related article: How to Get Rid of Tiny Yellow Bugs (Aphids) in 3 Easy Ways!

7. Fungal Diseases

Fungal diseases can also cause the yellowing of the plant.

Powdery mildew is a fungus that typically takes over the mint leaves.

If your mint plant is infected with powdery mildew, you can spot that easily by looking at the leaves—there will be powdery white and gray spots over the leaves.

To deal with it, use a suitable fungicide.

Try not to overwater the plant, as a moist root environment is a favorite place for the fungus to spread.

If the fungus takes over the entire plant, you may have to throw it out, as keeping it can lead to the spread of the infection. You can also burn the infected plant.

Watch this video to learn more about how you can care for your mint plant:

Why Are My Mint Leaves Turning Yellow – YouTube

With all that said, let’s head toward the conclusion.


Conclusion

I hope this answers your question—why are my mint leaves turning yellow? Mint leaves could be changing color for several different reasons.

Most of these reasons include environmental stressors and the inability to fulfill the conditions for perfect plant growth.

  • Give the mint plant the correct amount of water.
  • The sunlight exposure of this plant should also be balanced.
  • Make sure there is enough humidity in the air.
  • Nutrient deficiency can also cause the yellowing of the leaves.
  • More factors like pest infestations and different diseases could be involved as well.

Mint makes for a fantastic addition to your vegetable garden.

Take good care of it, and you will reap the fruits. If you have any experiences with your mint plant, share them with fellow gardeners in the comments below.

Regards!