Why Are My Mint Leaves Turning Purple? [4 Main Reasons]

Mint plants are pretty useful. They will always give you a fresh feel. And you can use it to make refreshing drinks too. Thus, it’s a bummer when you see purple leaves on it. 

So, let’s start with the question- why are my mint leaves turning purple

For starters, this situation will take place if your mint plant lacks phosphorus. You’ll also see the purple leaves if you don’t water the plant properly. Insufficient lighting and temperature can be another reason. Lastly, purple leaves can occur due to insects. 

Now, my friend, there’s more to this- 

To help the plant, you need to get to the root of the problem. That’s why we’ve explained every reason with its possible solution. 

Therefore, if you want to save your mint plant, read along!

It’s frustrating, isn’t it? 

Most certainly it’s disheartening to see your precious mint plant suffering. Especially since the reason behind this is probably you. 

Yup, purple leaves will start appearing on your mint plant-

If you don’t look after the plant properly. Your silly mistakes are the reason why your plant is sick right now! But hey you can fix this! 

To help you, we’ve explained your mistakes and their solutions-

Nutrient Deficiency

nutrient deficiency

Now, lack of nutrients is the first reason why the plant has purple leaves. 

A mint plant prefers soil that’s rich in phosphorus, nitrogen, and potassium. Therefore, if there’s a deficiency in one of the nutrients-

The plant won’t be able to get the preferred pH level of  6-7. And this will lead to the purple leaves. 

Now, even though we’ve mentioned three nutrients-

The purple leaves mostly appear due to phosphorus deficiency. Because this nutrient is needed for producing energy, nucleic acids, and sugars. Simply put, for food! 

So, if a plant lacks this nutrient-

They’ll stop growing and their leaves will start turning purple. Moreover, they’ll simply die if you don’t act quickly. 

How can you be sure that the problem is phosphorus deficiency? 

Well, you can run a soil test or analysis. This can be done by you or a soil lab. If you want to do the test, use a soil test kit. 

Just read the instructions of the kit and test your soil. This tool will let you know how much of the nutrient is missing in no time.


How to save the mint plant? 

To be honest, it’s not that hard to turn the situation back to normal. Therefore, just follow our lead-

Firstly, remove the affected leaves. We suggest cutting the leaves where their stems have begun. This way you can prevent damaging the plant’s tissues.

Once you’ve discarded the purple leaves-

Grab yourself a fertilizer that’s rich in phosphorus. Well, there are two fertilizers to use. You can either pick bone meal or phosphate.

We’ve mentioned how both fertilizers are supposed to be used-


How To Use

Bone meal

Add bone meal to the soil that’s on the edges of the pot. Make sure to loosen up the soil at first. 

Phosphate (Fast-releasing fertilizer)

Mix 1 teaspoon of the phosphate powder to 1 liter of water. Stir the mixture thoroughly and pour it into a 100 ml bottle. Lastly, add this to the plant’s soil every 15-20 days.

Now, this is how you can bring back the right amount of phosphorus. And help your plant get better!

Over or Underwatering

over or underwatering

Plants can go a long way if you provide the proper amount of water. Otherwise, they’ll give you signs that they’re suffering. Whether it be azalea showing black leaves or mint having purple leaves. 

So, how much water do mint plants need? 

Well, mint plants require a lot of watering. They need to be watered at least 2-3 days a week. 

You might have to water the plant more-

If you live in a dry area. Or where the average temperature is 28-39 degrees Fahrenheit in winter. And 69-78 degrees Fahrenheit in summer. However, by more, we mean watering the plant everyday morning. 

This way, you won’t be overwatering the plant. Also, if you didn’t know the plant’s roots can rot if it’s watered too much. This situation results in purple leaves.

Plus checking the soil before watering again is vital. Because if your drainage system is bad-

Watering regularly increases the chance of having purple leaves.


Now, if you have messed up while watering the plant, don’t worry! Instead, think about how to treat the plant now! 

Well, firstly, you’ve to check the soil to determine-

Whether you’ve under or overwatered the plant. If the soil is pretty wet, you’ve watered the plant too much. And it wasn’t able to absorb all of it. 

So, lift the plant up and put it into another container or pot. The pot should have at least 3-4 drainage holes. After replanting, be a bit patient. Because the water needs to be drained. 

Once you’re sure enough water has been drained, test the soil. Use a moisture meter to know whether the soil is moist or not. If it is, you can start watering again. 

Now, if you touch the soil and it’s completely dry. That means you haven’t provided enough water. And the poor plant is begging for some!

Therefore, quickly start providing water to your mint plant. Water till you see it coming out of the pot’s drainage holes. Then let the mint plant absorb the water through its roots. 

And that’s all! Hopefully, it’ll get better soon!

Insufficient Lighting & Wrong Temperature

Incorrect lighting and temperature can literally kill your plant with time. These poor living conditions aren’t just responsible for purple leaves. But also black leaves on peperomia

Now, mint plants thrive in bright places. This plant needs to be provided sunlight for 6-7 hours a day. They should be placed at least 8 hours under an LED light. Because this plant can’t produce food without the help of light. And this eventually makes the leaves purple. 

Now, checking the temperature is also necessary. The plant should be provided at least 65-70 degrees Fahrenheit in the daytime. And 55-60 degrees Fahrenheit at night time. 

Therefore, it’s best if the lighting is provided according to the temperature range. Both excess or insufficient lighting and temperature aren’t appreciated. 

Because too much heat will burn the leaves. While too little light and temperature will make the plant starve. Thus, the purple leaves will be seen on the plant.


If you detect that it’s due to insufficient lighting and temperature-

Move the mint plant to a place where there is enough sunlight. Or get yourself a full spectrum LED grow light. To keep the plant under that.

Now, before placing the plant under the light, check the temperature of that spot. If the temperature matches with the ideal one, you’re all good!

Infestation of Insects

Insects can definitely be a reason behind those purple leaves. Because they are well known for sucking the juice out of the leaf tissue. And this causes a plant’s leaves to lose chlorophyll.  

Now, you’ll mostly see spider mites, aphids, and thrips around your mint plant. Because these three love mint.


The treatment is pretty easy! And that’s using a plant-based pesticide. 

This way you won’t be harming the plant. But you’ll be able to remove the insects. We suggest using rubbing alcohol on the affected area. 

You can even apply homemade organic insecticides such as rosemary oil. These insecticides will definitely be helpful to get rid of the annoying insects!


Question: Can I eat purple mint leaves be eaten? 

Answer: Well, we don’t recommend you to eat the leaves. Because the plant is basically suffering right now. So, instead of eating the purple leaves, treat your mint plant. 

Question: Why do I have a mint with purple under leaves? 

Answer: There can be many factors responsible for this issue. For example, overwatering can be a reason. Then lack of phosphorus can be another reason. Lastly, insects can be blamed too. 

Question: Why are my mint leaves turning brown? 

Answer: The most common reason for brown mint leaves is insufficient water. If you don’t provide enough water, the plant will start drying out. And this will eventually lead it to have brown leaves.

Take Away

Now, those are the reasons why is my mint leaves turning purple. But over-fertilizing the plant can be another factor too.

So, where did you mess up? 

Share your answers and thoughts with us by leaving a comment. Good luck saving your precious mint plant!

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