Why Are My Mint Leaves Turning Black? (Causes and Solutions)

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Mint prefers moist soil, and too much dry soil may cause the leaves to turn black. Overwatering, on the other hand, will cause the leaves to rot and turn black. You may mist the plant between waterings or set the pot on a tray filled with pebbles to which you add water.

Mint leaves can become soggy and witty when exposed to low light. Lower leaves can become dry and eventually black as a result of this. As a result, you can still save it by cutting off the black leaves and exposing them to sunlight for 6-7 hours; however, do not overexpose it to sunlight for an extended period.

It’s a sign of trouble when mint leaves turn black. This may be as a result of a disease or exposure to extreme heat. Other causes may be due to a lack of attention to temperature, watering, and soil type. Mint leaves are simple to grow, but they need constant attention and care to stay healthy.

By identifying the problem early, this article will help your plant recover ultimately. 

What is a mint leaf?What is a mint leaf

Mint is a leafy plant that is most often associated with fresh breath due to the cooling sensation it produces in the mouth. Mint is widely used in toothpaste, mouthwash, breath mints, and chewing gum. The mint plant comes in various varieties, the majority of which belong to the genus Mentha.

Mint is a Mentha genus aromatic herb plant that proliferates. It is a fragrant perennial herb belonging to the Lamiaceae family’s Mentha genus.

What does mint look like?What does mint look like

Mint is a fragrant annual with toothed leaves and tiny purple, pink, or white flowers. It has a fruity, fragrant flavour. Mint comes in various colors and textures, all of which are fragrant, polished or soft, smooth or crinkled, bright green or variegated.

Mint leaves are well-known as a delectable appetiser. It stimulates digestive enzymes, which help to support the digestive system. Mint oil is antiseptic and antibacterial to help with indigestion, stomach infections, and other issues. The presence of methanol makes it an antispasmodic treatment. Plants flourish along marsh margins, meadows, stream banks, and forest fringes in their natural habitat, growing 12 to 36 inches tall at maturity.

Origins of Mint LeafOrigins of Mint Leaf

The majority of species are found in temperate Africa, Asia, or Europe, with a few exceptions in Australia and North America.

Mentha’s appealing fragrance comes from the presence of aromatic essential oils, which fill the surrounding area with a sweet scent. The bright fragrance and refreshing taste of the plants and the square stems that are characteristic of Lamiaceae family members make them easy to recognise.

The genus Mentha contains a diverse range of species that can be found in a variety of habitats. Wet conditions and damp soils are ideal for the majority of plants. Mints can reach a height of 10–120 cm (4–48 inches) and spread over an indefinite area. Some mints are considered intrusive because of their propensity to propagate unchecked.

Except for Antarctica, mint is native to all continents. The most widely used mint types are probably peppermint and spearmint, but there are many others, such as wild mint and water mint

Health Advantages

Mint has long been used in herbal medicine to treat a wide range of ailments. Unfortunately, apart from digestion assistance and irritable bowel syndrome relief, there aren’t many human studies recording the effects mint has on the body. With further testing, it’s possible that mint can be used to treat a broader range of ailments.

The health of the Mind

Mint is thought to be beneficial to the brain. Mint extracts were potentially shown to treat Alzheimer’s symptoms in one study, but further research is required. Another study found that inhaling peppermint improves memory and alertness, but it’s unclear if ingesting it has the same impact.

Good health Digestive System

When it comes to medicinal uses, mint is perhaps best known for its use as a digestive aid. Peppermint oil improves stomach discomfort and aids in treating irritable bowel syndrome without causing any adverse side effects.

Mint has been shown in studies to destroy bacteria, relieve stress, and combat cancerous tumour cells. To see if mint has these effects on the human body, human trials would be needed.

Causes of Mint Leaves Turning Black

mint leaves turning black
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  • Poor Drainage and Overwatering

You may have heard that mint plants need to be watered regularly beautiful, but be aware that overwatering can result in black or brown leaves on the bottom layer of the plant, as well as overgrown roots. Overwatering, in this case, refers to watering the mint plant once every one or two days, even though it is not summer.

Mint plants have exposed roots, so inadequate drainage systems will put the plant under even more stress. When the leaves are lovely and complete, you should suspect and check for an overgrown root because they are already a tenacious and fast-growing herb.

Remember that mint grows best in light soil with good drainage, allowing water to flow freely through it and keeps the roots healthy.

  • Temperature and Humidity

Mint is a fast-growing herb that prefers full sun to partial shade to survive. High temperatures will cause your mint plant to dry out or burn, resulting in black leaves. And this isn’t always accomplished by leaving the plant outside all day. Instead, this can happen within a few hours of being exposed to extreme weather.

As a result, it’s essential to keep your mint plant at the proper temperature of 69-84°F (21-29°C) while also shielding it from direct sunlight. Excessive heat also causes faster evaporation of water from the soil, which causes dry roots and slows your herb’s growth.

Mint plants, likewise, do not thrive in high-humidity conditions, even though they need warm temperatures. As a result, make sure you strike a balance between the two.

  • Fertilizing too much

Fertilizing the plant too much will stunt its growth and encourage weed growth. It becomes disease-prone, and the leaves gradually turn black. It’s known as fertilizer burn. Simultaneously, the soil may become depleted of nutrients, so fertilizing it once or twice a year is recommended to ensure adequate nutrient levels for plant development.

  • Rusty Mint

Mint rust is another common cause of black spots on mint leaves. A fungal spore infestation causes mint rust, and you’ll see mint leaves turning yellow or bright orange in late summer, in addition to black leaves. These colors will eventually fade to black over time.

  • Blight on the leaves

Mint leaf blight happens in the winter or when the weather is cold. When a plant enters a dormant period, the entire leaf turns black.

When you notice that winter is coming, consider shifting it to a colder place or exposing it to as much sunlight as possible. You should bring it inside to keep the temperature high. To prevent the spread of the disease, it’s best to separate them from other plants.

  • Low-light conditions

Mint leaves can become soggy and witty when exposed to low light. Lower leaves can become dry and eventually black as a result of this.

As a result, you can still save it by cutting off the black leaves and exposing them to sunlight for 6-7 hours. However, do not overexpose it to sunlight for an extended period. It will be tough to save your mint if the plant stem’s base is brown or black.

  • Aphid Mint

One of the insects that can make your mint leaves black is the Mint Aphid. Green, yellow, black, or brown is the most common colors.

Mint leaves become black and die as a result of aphid infestation. It can be treated with a block of insecticidal soap or neem oil.

Solutions of Mint Leaves Turning Black

Solutions of Mint Leaves Turning Black
source: https://garden.org/

  • How to Keep Mint Leaves from Turning Black Due to Overwatering and Poor Drainage

The first step is to pick and remove any blemished leaves from the plant that have turned black or brown. After that, make it a habit to water your plant less frequently, especially during calm or moderate months when the water does not evaporate quickly and collects around the roots. If the environment is humid enough, begin by watering every three to four days.

If any roots can be seen poking out of the drainage hole, you’ll need to either repot the plant in a larger container or divide it into two separate pots. You can either take a cutting or layer the plant to divide it in half.

If you don’t need two or more mint plants, on the other hand, you can move the existing plant to a larger container or pot. The additional room will allow the roots to spread and thrive.

  • How to Keep Mint Leaves from Turning Black Due to High Heat and Humidity

If your mint plant is suffering from excessive heat or sunshine, the first thing you can do is move it to a more relaxed or shadier place. Keep in mind that for your mint plant to grow and flourish, it will always need sunshine. As a result, put it somewhere where it can get some morning sun for a few hours while avoiding the noon sun’s heat.

  • How Do Mint Leaves Avoid Turning Black because of Mint Rust?

First and foremost, you want to isolate and take away the infected leaves from the plant’s remainder if you think the illness is during a gentle stage. Make sure the affected leaves are disposed of properly, either by burning or throwing them away. Solely certify, they don’t seem to be close to the potting soil in any case.

If that is the case, it is time to clear some areas to permit for higher aeration. Trim the plant’s surplus or withered mint leaves to accomplish this.

  • How does one apprehend if you have fertilized too much?

Salts will accumulate on the soil’s surface; use a pH scale tester to see its price.

If the reading is a smaller amount than seven, the number of salt within the soil is just too high; you’ll be able to cut back its presence by combining it with alternative soil and creating a potting combine.

  • How Do I Keep Mint Leaves From Turning Black because of Leaf Blight?

Before winter arrives, attempt moving your mint plant to a hotter location or keeping it during a location wherever it will get the maximum amount of daylight as doable.

If you notice any signs of zymosis, the primary step is to isolate it from near plants to stop it from spreading. To confirm that the rest of the mint stem grows well, interrupt the stem’s infected areas. Wash the remainder of the healthy mint leaves with H2O to confirm that there’s no plant transfer.

  • How to traumatise Low Lighting

Don’t let a scarcity of sunshine in your home limit you. With the help of artificial lightweight, you’ll be able still to cultivate mint and alternative herbs with none issues. If you do not have enough natural lightweight in your flat, think about using crystal rectifier lighting. It’ll solve your low-light downside.

  • How to Get eliminate Mint Aphids

If there’s an outsized variety of aphids, spraying pesticides on them can do the trick.

Mint CareMint Care

  • Light

Light mint plants grow best in partial shade. However, they’ll be fully grown in full sun if more often. Mint is one of the few preparation herbs that thrive within the shade.

Soil Mint thrives during a lush, slightly acidic pH scale vary of vi.5 to 7.0. If the soil is deficient, top-dress with the organic matter once a year Associate in Nursingd adds fertilizer once cutting off within the middle of the season.

  • Water

Mint has systematically wet soil with intelligent evacuation. Mint plants love water. However, they can not tolerate wet feet or soggy dirt. If the soil feels dry to the bit, add water. It’s in all probability best to water the plants very first thing within the morning so that they need lots of wet by the time the afternoon sun arrives.

  • Humidity and Temperature

The strength of your mints will vary, counting on the species. However, they’re adaptable. Mint thrives in atmospheric condition and might be fully grown in zones eleven and twelve. If you are growing mint inside, mist the plant between waterings or place the instrumentation on a water-filled receptacle of pebbles to extend wetness. Throughout the dry winter months, this can be notably vital.

  • Fertilizer

As new growth emerges within the early spring, feed instrumentation mint a healthy, general liquid fertilizer. After that, fertilize each four to 6 weeks for the remainder of the season. Potted plants that are perpetually moire lose nutrients additional quickly.

Types of MintTypes of Mint

  • Mints Citrus

Lemon mint contains a gentle lemon scent that isn’t to be confused with lemon balm. The lemon fragrance is extremely intense once the leaves of those mint plant varieties square measure crushed.

Lime mint has been legendary to irritate the skin and cause hypersensitive reactions. 

Orange mint plant varieties, like lime mint, are legendary to cause skin irritations in some and thus use caution once operating with or harvest citrus mints or higher; however, wear gloves.

  • Mints with a Fruit Flavor

Fruit-scented mints like pineapple, banana, and apple square measure delicious in iced teas or something with fruit, like sorbets, drinks, or cold desserts. They’ll be used as a garnish likewise. Once victimisation fruit-scented mint plant varieties in cookery dishes, concentrate on the varieties you decide.

Pineapple mint contains a sturdy pineapple scent. The scent of mint is barely discernible. Gum, toothpaste, and even solution contain volatile mint oil extracted from the leaves through a distillation method.

Fruit-scented mints like mango, banana, and apple square measure delicious in iced teas. Banana mint, as its name implies, smells rather like bananas. You’ll be able to add this mint to any dish that incorporates the employment of bananas or mint.

  • sprig of mint

Spearmint, like peppermint, makes a wonderful tea. These mint plant varieties square measure additional vigour than peppermint. Black-stem peppermint contains a more pungent scent than regular peppermint.

  • Peppermint with a Black Stem

The fragrance of black-stem peppermint is more significant than that of traditional peppermint. Because the name implies, the stems square measure darker in color. Tea made of black-stem peppermint is delicious.

  • Mint Chocolate

If grownup fully suns, chocolate mint can have a more robust flavour; however, it’ll conjointly stand up to partial shade. The leaves of those mint plant varieties have a patty scent to them. The aroma of chocolate is exceptionally sturdy.

Chocolate mint leaves may be substituted for regular mint in an exceeding range of desserts. Per the University of Golden State at Davis Extension, there are over 600 different mint plant varieties to settle on from.

  • Peppermint

Peppermint grows from underground rhizomes and, if left unchecked, can spread over a large region. When crushed, peppermint leaves and stems emit a familiar menthol odour, and this member of the Mint family has a variety of applications, including medicinal, culinary, and ornamental.

Some Important FAQs

These are some questions and answers commonly asked why mint leaves are turning black with problems and solutions. Here basically we try to give information about it. Check them out, and they may be of great help.

  • Why does my mint seem to be burnt?

Low humidity, excessive watering, and diseases such as fungal infections cause mint leaves to turn brown. Nutrient deficiency, heat scorching, limited roots, or ageing are less likely causes.

  • What species are attracted to mint?

Beneficial Insects Attract Mint. Allow your mint to bloom, and bees, beneficial wasps, hoverflies, and tachinid flies can visit. 

  • Is it okay to eat mint leaves that have holes in them?

So, would you eat indoor herb leaves with holes in them? The leaves are healthy to eat if insects or diseases cause the hole. However, a herb that an animal has damaged should be avoided and thrown away because the possibility of disease transmission is high if ingested.

  • What are you going to do with black mint leaves?

In stews, soups, and Peruvian cuisine, black Peruvian mint is used as a condiment. Herb marinades for poultry, beef, and seafood can be made with it. The excellent, clean flavour of black Peruvian mint is beneficial in chilled desserts that require a sharp effervescent consistency.


It’s a sign of trouble when mint leaves turn black. This may be as a result of a disease or exposure to extreme heat. Other causes may be due to a lack of attention to temperature, watering, and soil type. Mint leaves are simple to grow, but they need constant attention and care to stay healthy.

Although proper plant care isn’t a guarantee against diseases like mint rust and leaf blight, it helps keep your plants safe. Mint should be grown in full sun or light shade, and the soil should be kept moist at all times. Mint spreads quickly and can become invasive. Plant this fragrant herb in a wide container if necessary to prevent it from spreading.

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