Peace lily leaves turning black can be a major shock for any loving plant parent. It not only looks bad, but also means that your plant is sick and unhappy.

leaves of a peace lily spathiphyllum plantHowever, you need not worry. This all-encompassing guide lists the seven most common reasons behind this problem, and you will also learn how to solve the issue like a total pro.

Why Are My Peace Lily Leaves Turning Black?

Your peace lily might be suffering from black discolored leaves for various reasons such as old age, overfertilizing or pest attacks. Maybe there is a lapse in plant care, such as underwatering or an especially large pot. Other common reasons include hard water, pests, and fungal diseases.

Read about all of these issues here.

– Old Age

Sometimes, peace lilies simply shed their leaves off when they are old enough. A lot of these turn black or brown before they eventually fall off.

This is a natural phenomenon and nothing to worry about. If the discolored leaves are bad in appearance, simply prune them off instead of waiting for them to shed.

– Underwatering

Inadequate and improper watering are often responsible for water lily leaves turning black. This is a plant that likes its soil to be consistently moist. When even the top inch dries up, you must give it water immediately. 

Allowing the soil to dry more than an inch from the top will lead to the withering of the leaves. Eventually, the supply of nutrients from the roots to the upper parts becomes affected. The leaves lose their green color, turning first yellow and then brown and black.

Another important factor is inconsistent watering. If you water your plant regularly for a week and then forget about it for the next two weeks, this too will affect the leaves adversely.

– Overfertilizing

Fertilizing too much is never a good thing for peace lilies. The accumulation of fertilizer contents in the soil produces a mineral and pH imbalance. This disturbs the uptake of nutrients from the soil by the plant. 

Using chemical fertilizers without diluting them first causes chemical burns to the roots of the plant. This causes the leaves to become necrosed. Consequently, your plant will end up developing black or yellow leaves.

– Pot Is Too Large

If you have recently repotted your peace lily in a larger pot, this could be responsible for its leaves turning brown or black. If the pot size is too large, the roots have a harder time getting all the necessary nutrients.

Additionally, water also takes far longer to evaporate from a larger pot. This collected water is often conducive to several fungal and pest problems, leading to the dreaded black leaves.

– Water Quality Is Poor

Your peace lily turning black can be because of poor water quality. This happens when using common tap water instead of rain or distilled water. If the tap water has too much salt and mineral concentration, these will collect in the soil over time.

A high concentration of salts in the soil blocks water from entering the roots. These salts also disrupt the pH balance and cause chemical burns. Your peace lilies will end up turning black in this environment.

– Under Attack by Pests

Are your leaves turning yellow, brown, or black without apparent cause? Are the leaves lifeless and have begun to droop despite you diligently fulfilling all peace lily care needs? This could mean that it is under attack by pests.

The most common pests that come to mind include mealybugs, spider mites, aphids, and scale insects. These are all suckers and puncture the plant to eat its sap. They thrive mostly under moist and warm conditions.

You will discover large pest colonies hiding under the black or brown leaves, while some pests burrow deep into the stem sheath. They also love to jump from one plant to the next, rapidly spreading the infestation.

– Root Rot

Fungal root rot almost always manifests as black spots appearing all over the affected peace lilies. Not only do the peace lily leaves turn black but swollen and mushy as well. It would be best if you looked out for other symptoms of rot: rotten smell, drooping leaves, and peace lily black stems. 

What is responsible for the development of fungal rot in plants? This happens when your watering frequency doesn’t allow the topsoil to dry, leading to overwatering. Poor soil drainage or the pot itself may also be probable causes.

How To Treat Black Leaves on Peace Lily

If you want to treat peace lily leaves turning black and yellow, you need to eliminate the causative factor. This includes taking steps such as improved watering, flushing out fertilizer, using a suitable pot, and using distilled water. 

It would be best if you also got rid of bugs and fungal diseases as they are one of the most common causes of leaves turning black. Learn about all the treatment options below.

– Water Consistently 

If the leaves of your peace lily plant have turned black due to underwatering, there is still hope. Improving your watering habits will turn them green again in no time. 

Keep a constant check on your soil. If its surface feels like it has dried, you need to water the plant asap. Always use copious amounts of water each time. 

Pour water towards the soil until it starts draining from the drainage hole. Collect all the draining water in the drip tray and discard it immediately. Also, make sure that you water consistently and on time.

– Flush Out Your Fertilizer

If your fertilizer is causing black leaves, you must flush it out of your potting soil. You can confirm this by sending your soil sample to a nearby lab

Take one to two gallons of water and start pouring it on your soil from the surface. This will cause all the build-up toxins to flush away. Make sure you use distilled water only because any other water would cause further salt accumulation. 

Afterward, only fertilize three to four times during each growing season. Don’t forget to dilute the fertilizer beforehand.

– Use a Suitable-sized Pot

When transplanting your peace lily from one pot to the next, choose the right size first. The new pot should only be larger than the previous one by 2 inches at most. This plant doesn’t grow well in very large pots.

Good drainage is the second most important thing to look for in a pot. Ensure that the pot’s bottom has an adequate number of drainage holes. Pots made of terracotta or clay materials are naturally superior to plastic ones. Whatever you do, don’t go for glass or metal pots.

 

– Use Rainwater or Distilled Water

If your plant has been suffering due to common water usage, you need to take immediate action. Use distilled water to flush out and drain the toxins accumulated in the soil.

Afterward, resort to using only distilled water or filtered water. Trust us; this will solve most of your watering issues. It is best if you collect rainwater and use it since this is the most natural for them.

If you must use tap water, then at the very least leave it exposed overnight. The chlorine will evaporate from this water, making it a bit safer.

– Get Rid of Pests

If you have a pest problem, worry not because it is super easy to get rid of them. Your peace lily plant will soon return to normal if you follow the easy steps below.

Wash Your Plant

Take your peace lily along with its pot to a sink. Let the water flow through the soil for at least five minutes. Many pests and bugs attacking your plant will easily fall off just by washing. You can add insecticidal soap to the water for a better effect.

You should also take a cotton roll or a toothbrush and scrub these pests off the surface of your plant.

Use Neem Oil

Neem oil is a wonderful substance when it comes to killing pests. It will get rid of the bugs while at the same time not harming your plant. You can dab a Q-tip in this oil and apply it directly to pest colonies under the leaves. 

This oil can also be used in the form of a spray. The easiest method is to fill a bucket with a gallon of water and add one to two tablespoons of neem oil. You can now use this spray every week on your infested peace lily.

Other Homemade Solutions

Baking soda is the average kitchen ingredient you can use to fight against pests. Mix one tablespoon of baking soda in about a gallon of water thoroughly. Then spray this mixture on the plant in question once or twice weekly for a rapid effect.

Vinegar is another edible from your pantry that you can whip out against pests. Either go for a foliar spray by mixing vinegar in water, or you can also dilute vinegar and then apply it directly to the colonies of pests under the leaves.

Insecticides

This option is perfect for those that don’t have much time on their hands for plant maintenance. Plenty of insecticides are available in the market. It would help if you went for a moderate yet environmentally friendly insecticide.

Even so, it would help if you took care to protect yourself while spraying insecticides. Make sure your bare skin is not exposed, and wear safety goggles for eye protection.

The insecticidal spray regime you need to follow should be according to the instructions on the label. Follow the instructions on the label during the application.

– Treat Rot the Right Way

Fungal rot might look horrible, but it is not that hard to eliminate. You can revive your rotten plant with black leaves with only a little time and patience. Other fungal infections like leaf spot can also be treated the same way.

Here is how you can treat rot infections.

Depot the Plant

What you need to do first is to take your peace lily out of its current pot. Take care while at it because the roots are already fragile. We always water the soil deeply one day before until the soil becomes very soft. This makes it much easier to rake the soil and pull the plant up.

The infected soil and pot need to go for good. You cannot reuse them. Place the depotted plant on a piece of newspaper which will absorb its moisture.

Cut off All the Rotten Parts

Let the newspaper soak all the water from the mushy roots of your rotten peace lily, then take a look at the plant. Some parts might be only mildly rotten, while others might be completely black. These parts need to be cut off and discarded. Take the sharpest shears and chop the blackened peace lily flowers, leaves, stems, and roots off.

Don’t forget to wash and sterilize the shears after use. Rub 70 percent isopropyl on them to kill off all fungal matter.

Spray With a Strong Fungicidal Agent

The strongest antifungal agent in the market nowadays is the liquid copper fungicide spray. You can order them easily these days. Spraying instructions will be given on the packet. It’s best if you follow the guidelines given by the company. 

One tablespoon of neem oil and vegetable oil mixed in a gallon of water acts as a natural fungicide. This is best for those who don’t want to expose their peace lily houseplant to harsh chemicals.

Repot Again

After all the excess moisture in the plant has been dried up, you can pot this plant again. Prepare a new pot and fill it halfway with the potting mix of your choice. Carefully place the plant in the new pot, and then add the rest of the soil. Take your plant somewhere with bright indirect light and plenty of warmth.

Peace lily leaves

Conclusion

We have now covered everything on why peace lily leaves turn black. That is why a quick recap is a must.

  • You can tackle blackened leaves in peace lilies by not watering them regularly.
  • Sometimes, these black-colored leaves are simply due to old age when the plant is shedding its old leaves.
  • You must flush the plant thoroughly with water if this condition is due to over-fertilizing.
  • If pests and rot are the culprits, then the proper treatment protocol must be followed.

After reading our guide, you are ready to tackle that black foliage in your peace lilies.

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