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How to Fix Plant Leaves Turning Black?

There are different plants in the plant kingdom; one thing common in most of them is their signature green leaves.

People usually grow household plants for the color and beauty that comes with them. But sometimes, due to certain anomalies, their leaves may turn black.

Generally, plant leaves turn black for improper watering, improper lighting, fertilizing problem, temperature stress, improper humidity, common pests and diseases, and physical damage.

Black leaves on plants
Black leaves on plants can be a devastating scene for gardeners to witness.

Plant leaves turning black usually does not happen and is a rare phenomenon to witness.

If your plants have the same problem, you would want to fix that. Please continue reading to discover why plants turn black and how to fix them.

Why is my Plant Leaves Turning Black?

Black leaves in plants can be an eyesore for any enthusiastic plant lover.

Although, if the whole leaves have turned black, it may be some kind of aesthetic view to look at.

But, the leaves turning black for the plants can indicate disease infection, overwatering, pest infestation, or overfertilization.

To take any recovery action, you need to find the root cause of the leaves blackening.

Some plants famous for their glossy green leaves, like the money plant, Chinese money plant, curry leaf plant, kiwi plant, etc., can turn black under improper growing conditions.

However, if you notice any black marks on the prayer plant or the aluminum plant, those could be the variegations that they had developed.

The leaves that have turned black have a lesser chance of being reverted to green and will eventually fall off the plant.

Let us look at the causes of plant leaves turning black and how to fix them.

1. Improper Watering

Except for some desert plants, most plants in the plant kingdom are affected badly if you improperly water them.

Each plant has certain watering needs; if a gardener does not pay attention to the details, they face the consequences.

Generally, if you overwater or underwater any plants, the stress will build up on the plant, and their leaves will start turning black.

Peace lily leaves black
Improper watering can be a primary cause of why plant leaves go black.

Overwatering causes root rot, which inhibits nutrient and water uptake and airflow exchange.  

As a result, the plants don’t receive enough water and nutrients, and their leaves eventually turn black.

On the other hand, the plant cannot gather the required water content due to underwatering, which can turn the leaves black.

Let us look below for other under and overwatering symptoms to pinpoint the exact cause.

UnderwateringOverwatering
Dry SoilMushy Leaves
Plant WiltingYellowing Leaves
Slow and Stunted GrowthLeaves Fall off Abruptly
Brown Leaf Tips and EdgesRoot Rot

Treatment and Preventive Measures

  • If the reason is underwatering, you must soak the pot in water immediately.
  • You can fill a bathtub with water and immerse your pot in it till the bubbles stop forming.
  • For overwatering, stop watering the plant for some days and resume once it has recovered.
  • If your plant has incurred root rot, take a new pot, fill it with fresh, suitable potting mix and repot your plant.
  • Before repotting, trim off all the mushy and brown parts of the root and remove the plant’s damaged parts.

Water requirements differ depending on the nature of plants. So, understand your plant’s needs and water accordingly.

Generally, water your plants once the top 2 inches of soil have dried out, or use a watering scheduling app.

Make sure the pot you are using has enough drainage holes.

Learn more about the watering requirements of various houseplants.

2. Improper Lighting

Light requirements differ from plant to plant and are usually determined by the plant’s native zone.

For instance, flowering plants like Sunflowers, Marigolds, Salvia, etc., require a relatively high amount of light, while ZZ plants, Snake plants, Pothos, etc., can survive in low light.

Generally, the leaves turn black if the plants get too saturated with light and receive more light than they should.

Leaves-turning-black
If the light conditions are not to the point, plants show stress by turning their leaves black.

Low light can also induce problems in plants, but their leaves will not turn black.

In extreme light conditions, the plant molecules absorb too much light and create harmful oxygen species, which can turn the leaves black.

Other symptoms of too much light include dry, crispy, droopy leaves, brown patches, sunburnt leaves, yellow leaves, etc.

Read more to learn about the importance of light color for plants growth.

Treatment and Preventive Measures

  • Relocate your plant to a location where it will get only the required amount of light and not more.
  • If the plant is immovable, place some shades between the plant and the light source.
  • Provide the plants with direct morning sunlight for about 2 to 3 hours daily.
  • Rotate the plant occasionally to make sure it gets the light uniformly.
  • Place your indoor plants in an east-facing window where they will receive at least 4 hours of bright indirect sunlight.
  • Keep your indoor plants under grow light for about 12 to 14 hours if they are not getting enough sunlight.

Find out more about the various houseplants light requirements.

3. Improper Fertilization

Avid gardeners like you and me prefer to see our plants grow full-fledged, and we want them to do it quickly.

So what do we do? We use fertilizers on our plants. Sometimes it works out perfectly, but sometimes it backfires.

Generally, a lack of fertilizers results in black leaves. Phosphorus deficiency causes the plant’s leaves to turn dark green with hints of purple and black.

Lack of fertilzier
Phosphorus is an important nutrient required for the plant. If it lacks Phosphorus, the leaves will turn blackish-purple.

Phosphorus in plants works as the building block by converting the sun’s energy to elements important for the plant’s growth.

The lack of fertilizers in plants will cause them to have slow growth, produce lower-quality leaves, lose root mass, etc.

On the other hand, excessive fertilization can also result in the leaves turning black.

In particular, too much nitrogen can cause the leaves to become mushy and soft, making the plant more vulnerable to diseases like powdery mildew and root rot.

As a result, the plant leaves may turn black and eventually die.

Treatment and Preventive Measures

  • Fertilize your plant immediately using a fertilizer with a high amount of Phosphorus.
  • However, do not overdo fertilization, as the plant can suffer grave consequences.
  • Occasionally feed your plants organic fertilizers to maintain the nutrient content.
  • Flush your plants with tepid water to balance the soil pH.
  • Dilute the fertilizer to 1/4th strength.
  • Use fertilizers like superphosphate and bone meal to restore the fertilizer content in the soil.
  • Flush out excess fertilizer by running the pot under tap water to treat overfertilized plants.
  • Trim any damaged stems and leaves, then repot the plant in new potting soil.

Read more to learn about fertilizer requirement for various houseplants.

4. Temperature Stress

Temperature is one of the most important factors in a plant’s growth. Most plants cannot survive extreme temperature fluctuations and conditions.

Generally, if the plant faces too much or too less temperature than it can handle, its leaves will gradually turn black.

Most plants have a good threshold for higher temperatures but succumb to freezing temperatures.

Plants like Caladium, Euphorbia, Salvia, etc. can survive at high-temperature while Christmas cactus, Siberian Iris, Peony, etc. can survive low temperatures.

In high temperatures, the plant photosynthesis rate drops. Similarly, the plant cells freeze in low temperatures, resulting in black, dead leaves.

Let us look at other symptoms of plants’ low and high-temperature damage.

Low TemperatureHigh Temperature
Leaves lose their colorDamaged fruits
Leaves turn purpleLeaves and stem scorch
Slow growth of plantShriveled leaves

Treatment and Preventive Measures

  • If the plant has incurred high-temperature damage, move to a cooler, shady area.
  • Water the plant thoroughly with cool water in the morning and put them in the shade for some time.
  • Keep the pots in a room with an air cooler but keep the humidity in check.
  • During low-temperature damage, move the plant indoors to protect it from cooler drafts.
  • Keep them on top of heating pads to provide instant heat.
  • You can buy houseplant mulch and put it on the soil line of your pot to prevent heat from escaping.

5. Improper Humidity

Depending on their native zone, plants have different humidity requirements.

However, most houseplants’ proper humidity ranges from 40 to 60%. Some plants may need more humidity, some less.

Generally, if the humidity is too low or too high for the plant’s liking, it will show stress by turning its leaves black.

Humidity needs of Mini Watermelon Peperomia
The average indoor humidity level, i.e., 40-60%, will be ideal for most of your houseplants.

Leaf cells lose more water in low-humidity conditions, changing the structure of the cell. As a result, the cells are killed, and the leaves turn black.

Similarly, in highly humid conditions, different fungal diseases affect the plant, causing them to turn its leaves black.

I have listed other high humidity and low humidity damage symptoms on the plants below.

Low HumidityHigh Humidity
Curling of leavesLoss of leaves and stems
Leaf scorchWilted appearance
Browning of leavesEventual death of plant

Treatment and Preventive Measures

  • Place a humidifier or a wet pebble tray near the plant to boost humidity instantly.
  • You can also manually mist the plant using a bottle spray.
  • Move the plant to high-humidity areas of your house, like the kitchen or bathroom.
  • Group certain similar-natured plants and create a ‘humidity-sharing’ environment.
  • Do not put your plant in the direct path of air conditioner vents or radiators.
  • You can also use a dehumidifier in highly humid conditions to reduce the humidity.
  • Keep the plants individually in different locations to reduce the humidity.
  • Place your plant in an area with a constant flow of air to reduce the plant’s humidity.

6. Infestation of Pests

Pests are hardy, pesky little bugs that attack your plant and suck them out of their juicy sap.

Most plants are hardy, and the pests cannot cause much damage. However, certain environmental factors make plants more vulnerable to pest infestations.

Generally, one common pest is aphid which can cause your leaves to turn black.

Aphids on plants
Aphids can attack almost every houseplant and cause them to turn their leaves black.

Aphids affect your plant and feed on their juices. After a while, they release honeydew, providing growing ground for sooty mold.

These bugs do not need any particular condition to attack your plant. They see a plant; they attack it.

You can recognize them by their pear-shaped body and long antennae. They make the plant curl its leaves, turn yellow, and have stunted growth.

Treatment and Preventive Measures

  • If the infected parts have been destroyed beyond repair, you should just trim them off the plant.
  • Spray your plant with neem oil or any other horticultural oil.
  • Dip a cotton ball in rubbing alcohol and apply it to your plant’s leaves.
  • You can spray your plant with high-pressure water to eliminate aphids.
  • Properly inspect the plants before bringing them inside your house.
  • Do not overwater your plant, and maintain proper sanitation.

Read more: How to identify insect eggs on leaves and treat pest infestation?

7. Fungal and Bacterial Diseases

Not exactly the black leaves, but certain diseases can cause black spots to appear in your plants.

Generally, diseases like Cercospora leaf spot, Rhizoctonia leaf spot, Anthracnose, Rhizoctonia leaf spot, Phyllosticta leaf spot, Mycosphaerella ring spot, etc., can attack the plants.

Most of these diseases are deadly and can eventually kill the plant. So, it would be best if you could prevent these diseases overall.

Let us look at the diseases and their symptoms on plants.

Name of DiseaseSymptoms
Southern blight or
Sclerotium stem rot
Brown mushy area at the soil line of the cutting
Loss of color at lower foliage
Phyllosticta leaf spotDark brown to black rings spreading all across the leaf
AnthracnoseWithering, wilting and drying plant tissues

Dark spots or dark crisscross bars over the leaf
Mycosphaerella ring spotRing of light or dark pigmentation

Leaf distortion and stunted plant growth
Rhizoctonia leaf spotMushy dark brown spots on the plant

Plant has withered or shriveled appearance
Cercospora leaf spotBrown or black spots on the bottom of the older leaves

Leaves turn necrotic

Treatment Measures

  • Immediately remove all the affected and dead parts from the plant and destroy them.
  • If the infection has spread beyond repair, discard the plant altogether.
  • Place the plant in a bright location and improve the soil aeration and drainage.
  • Solarization, cultural manipulations, and cultural amendments are effective against Southern blight.
  • Ring spot virus has no treatments, so it is better to prevent it altogether.
  • Use fungicides like Gardensafe, Bonide, and Dr. Earth to eliminate fungal diseases.

Preventive Measures

  • Maintain proper sanitation around the plant by removing dead parts and dusting off the leaves.
  • Most of the diseases are attracted by overwatering and too much humidity. So, it is best to avoid these.
  • If any plants are unhealthy, it is better to isolate them.
  • Ensure proper air circulation is maintained around the plant and in its soil.
  • Water your plant early in the morning so the sun can dry out excess water.

8. Physical Damage

Sometimes even a petty thing like touching your plant can cause its leaves to turn black.

Young and new growths are more susceptible to physical damage as their core strength has not developed yet.

Other factors like pets and kids can also destroy plant tissues by tearing or chewing off them.

Be on the safer side by placing toxic plants away from your kids and pets.

Treatment and Preventive Measures

  • Remove the damaged part from the plant.
  • Keep fragile plants away from pets and kids.
  • Do not relocate your plant every now and often.

Care Tips for Houseplants

To prevent the above problems, you can look at the table below to know the optimum requirement for your plants.

ParametersAroidsSucculentsTrailersAromatic HerbsOrnamental Flowers
WateringOnce every week in summer
Once every 15 days in winter
Every 2-3 weeks in summer
Once the entire season
Once a day in summer
Once every 15 days in winter
Once every week in summer
In winter, water once the top 1 inch of the soil is dry
Soak the plant once a week in summer
Water once a month in winter
Temperature
60-85°F
40-80°F65-80°F55-70°F55-68°F
Humidity
40-60%
80%40-50%
LightingBright, indirect, filtered sunlightFour to six hours of bright, indirect sunlight everydayMedium-bright, indirect sunlightAt least six hours of direct sunlight dailyHigh-intensity light
Infrared light is best for flowering
FertilizersBalanced NPK fertilizer every 3-6 monthsBalanced organic fertilizer once a monthLiquid fertilizer every 1-3 weeksAll-natural organic fertilizer at the start of the seasonFertilizers rich in phosphorus every two to three weeks

Should I Cut off Black Leaves?

This is one of the questions that may linger in the minds of even professional gardeners.

So before jumping into this question, you must understand the nature of the plant’s leaves blackening.

Pruning-plant-leaves
You need to understand the nature of the blackening before cutting the leaves off.

If the cause of the black leaves is fungal diseases and pests, there is next to no chance that they will recover.

But if the reasons are temperature, sunlight, water, etc., they may be reversible.

So, before deciding whether to cut off the black leaves or not, understand the nature of the damage.

Conclusion

Plant leaves turning black is a sight you would not want to witness on your plants. So, be the better plant parent and prevent it altogether.

I lost a few of my plants to black leaves, which made me research and amass information about them.

May you never go through what I had to. 

Happy Gardening!

Read our articles on Orchid leaves black spots and Monstera leaves turning black.

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