Why Are My Peace Lily Leaves Turning Black?

Black leaves on your prized indoor plants can be rather unsettling. Moreso on a plant known for being especially beautiful, and for having gleaming, emerald foliage.

So, understanding why your Peace lily’s leaves have been affected by this scourge, and what you can do to fix it, and ensure the like never occurs again is bound to be high up on your list of houseplant priorities.

Peace Lily Leaves Turning Black

A Peace Lily with black leaves can set alarm bells ringing for the best of us but before you start taking drastic action, take a minute to read this article. It covers all the most common reasons this houseplant’s favorite might be producing black leaves and exactly what you need to do to fix it.

What Causes The Leaves Of A Peace Lily To Turn Black

The pattern or type of discoloration affecting your plant counts when you’re attempting to diagnose the issue. Some of the most common include:

Peace Lily Leaves Turning Black

Black leaves are most often due to drought leading to a lack of water in the plant’s cells as a result.

As more water leaves the plant during transpiration, it is unable to replace it resulting in the subsequent desiccation and blackening of its leaves like the leaves in this image.

Peace Lily Leaves Turning Black
Under Watering

That said, blackened leaves could also be due to a plethora of other factors including:

  • Excessive or insufficient watering
  • Disease via infection
  • Lighting issues
  • Pests
  • Unfiltered water
  • Over fertilizing
  • Temperature shock
  • Low humidity

These issues will normally manifest in the form of black, brown, or yellow leaves and even the presence of black spots.

The following sections provide pointers to enable you to diagnose the cause of these issues and exactly what you need to do to resolve them.

Leaves Turning Black And Yellow

The causes of this pattern of discoloration may be due to:

Excessive watering: Providing water in excessive quantities may result in your Peace lily’s leaves turning yellow and black.

Lighting issues: Direct exposure to sunlight is another problem that can see your plant’s leaves to turn yellow with dark spots. Yellowing – rather than black and yellow leaves – is usually due to insufficient exposure to light.

Pests: Spider mites and mealybugs which are known to attack humidity-loving indoor plants can also cause your peace lilies to have black speckled leaves which can also turn yellow. 

Peace Lily Leaves With Black Tips

Here are the main causes that can contribute to your Peace lily developing black tips, but it often seen earlier with leaves displaying browing, then potentially turning black.

Unfiltered water: Peace lilies are sensitive to the presence of chlorine and other chemicals in tap water.

Continuous use of unfiltered water can cause the tips of your plant’s leaves to darken as a result. Leading to crisp black edges.

peace lily turning black at tips
Crisp Black Edges

Overzealous fertilizing: Fertilizing too often or using more fertilizer than is required, may cause your Peace lily to suffer root or foliage burn. 

Temperature shock: Suddenly plummeting temperatures can give your Peace lily a nasty shock. Anything below 60°F (15.5°C) can start affecting your Peace lily’s ability to function effectively.

Should temperatures fall further to 45°F (7.2°C) or below, your peace lily may not be able to handle the chill.  One of the signs of temperature shock is the blackening of the leaves from the edges. If left the plant may not survive. 

Low humidity: Peace lilies thrive in the presence of high humidity. Especially since it will slow their rate of transpiration.

The reverse is the case in areas with low humidity where increased rates of transpiration will lead to darkening leaf tips as more moisture is drawn from the plant into the surrounding air.

Viral , Bacterial or Fungal infections: Although they are absent from the commercial potting mix, microbes can actually invade it.

One such example is pythium which can find its way into your plant pot by way of fungus gnats which are attracted to damp soil.

Once present, it can cause root rot which in turn will darken the leaves of the plant first.

peace lily leaves black with disease
Microbial infections

Black Spots On Peace Lily Roots

Root rot is the main culprit of black spots on the roots of your Peace lily. This itself is due to overwatering or soggy soil and can result in those white roots darkening before taking on a slimy texture and ultimately rotting.

The peace lily’s leaves will display black spots once the condition is more advanced. Should it progress further, the stems and leaves of the plant will darken and become mushy in texture.

I recommend checking the condition of the roots while you are repotting. Simply brush off the soil gently and check to see that the roots are firm and white or cream-colored.

In the event of noticing any black spots, snip away the affected roots to prevent the spread of infection. The shears or knife you use should be disinfected before use and after each cut to prevent unaffected roots from becoming infected.

Peace Lily Leaves Turning Black And How To Fix It

Once you’ve ascertained the cause of the issue, you can move on to being able to fix it. As you would expect, timing is crucial, as is moving promptly to avoid further delay and being successful in resolving the problem.

Here are detailed steps you can take once you’ve worked out what the problem is:

Overwater Or Underwatering

Overwatering can result in drenched soil which can, in turn, cause harmful microbes in it to thrive.  

This could give rise to root rot which can have serious consequences for your Peace lily.

The key here is a balance that can be attained by checking the upper 2 inches of the soil for moisture. If it is dry, then your plant will need watering. 

Peace lilies need to be planted in a pot with good-sized drainage holes as this allows excess water to drain freely from the bottom of the pot and will help to prevent soggy soil. I prefer to stand my pots in the sink while I’m watering so that all the excess water drains off rather than pooling in the drip tray.

Doing so will ensure the soil is moist, but not soaked. 

How Often Should You Water A Peace Lily?

I test the moistness of the soil by placing 2 fingers about 2 inches deep into the pot. If it’s dry then I know it’s time to water. Peace lilies are also great at letting you know if they need a drink because their leaves and blooms will droop.

Using Distilled Or Bottled Water For Peace Lily

Peace lilies are sensitive to the chemicals in tap water meaning distilled or bottled water is a better option when watering them.

Buying bottled water throws up all manner of environmental and cost issues but you can circumvent this by leaving out your tap water overnight to allow the chemicals in it to dissipate before using it to water your houseplant.

Soil Conditions

Peace lilies detest drenched soil and soggy roots. That means only using pots that have drainage holes at the bottom and ensuring the soil is thoroughly drained after each watering session.

Because they don’t like dry soil either, check soil moisture frequently for dryness to avoid the potential for drought stress.

Too Much Direct Sunlight

Peace lilies are none too fond of direct sunlight and will begin to develop darkened tips if exposed to it. 

As a result, it is best to place your houseplant close to windows that receive early morning sunlight; it should be kept out of the direct path of the light, but close enough to it.

Low Humidity

Owing to their origins in tropical forest regions, Peace lilies are accustomed to high humidity. As a result, ambient levels should be maintained at 50% or 60%.

Regular misting can help with raising humidity levels or even placing the plant on top of gravel which stands in very shallow water. 

Alternatively, you could also place your plant amid other tropical and humidity-loving houseplants, where it would be able to bask in the moisture they release into the air.

Over Fertilizing

As a rule, shade-tolerant species require less fertilizer than other houseplants. Hence, when fertilizing your Peace lily, it is best to err on the side of caution. To avoid overfeeding, the Clemson Cooperative Extension advises using a quarter of the recommended amount if you happen to be using a fertilizer specifically manufactured for houseplants.

If applied in excessive amounts, fertilizer can cause the buildup of salts in the soil. This in turn can make the roots of your peace lily shrivel up, affecting their ability to absorb water and nutrients. Their reduced function can lead to leaves turning black at their margins, yellowing, and even wilting.

When To Fertilize Peace Lily

Peace lilies should be fed fortnightly in the spring and summer and every six weeks in the fall and winter.

Pests

Pests can affect the health of your leaves. Some of them such as arachnids or insects can cause them to darken and turn black. Below some of the most common culprits which are likely to do just that are examined in greater detail.

Common Pests On Peace Lily

Some of the main pests you may have to contend with in this regard are mealybugs and spider mites. In this subsection, I explain how you can identify them, what issues they cause, and how you can rid your floral friend of these arthropod invaders.

Mealybugs: Cousins to scale insects, mealybugs are identifiable by their long antennae, oval-shaped bodies, multiple appendages, and pale waxy covering. They hail from the tropics and actually prefer perennials, just like your peace lily.

No part of a plant is out of bounds to this creepy crawlies. Not even its roots. What’s more, they are prolific at reproduction: depending on what species subset they belong to, they may either give birth to their young life or simply hatch 600 eggs. Either way, a new generation will spawn on your peace lily every 4 – 12 weeks.

Mealybugs love plant sap. They’re also pretty voracious and can pose a serious problem to crop plants in warmer climates. They love to attack leaves at the point where they join the stem which can cause them to turn yellow and eventually fall off.

In addition to their sap-sucking activities, mealybugs also leave honeydew in their wake which in turn can cause the growth of sooty mold fungi. Although harmless, the mold can affect photosynthesis when present in high concentrations.

Spider Mites: Cousins to spiders, they seem like tiny specs in motion at a first glance. They love to live in colonies on leaves’ undersides and produce a distinguishable web matting. They’re known to be fond of vegetables: think tomatoes, melons, and sweetcorn. However, they are by no means averse to settling on your peace lily.

Spider mites are capable of laying 200 eggs and of rushing through their entire lifecycle in just 7 days. These arachnids are also capable of targeting the cells of your peace lily and draining them for sustenance.

The result: yellowing, bronzing and eventually shedding — which could affect the overall health of your peace lily.

How To Treat A Pest Infestation On Peace Lily

When it comes to getting rid of these arthropods, bug spray may not always be effective; in the case of mealybugs, their waxy coverings may offer them some protection.

Hence, vigilance is highly recommended to prevent these bugs from making it into your home in the first place. Especially since they can infect other plants. Every new plant must be inspected thoroughly and only brought indoors once it has been deemed to be bug-free.

In the event of their making it indoors, neem oil is one of your best bets. It’s safe to use too.

Rubbing alcohol is also another excellent remedy. Simply soak some cotton in it and dab at the intruders while taking care not to touch the plant itself with the alcohol.

Black Leaves On Peace Lily After Propagating

The occasional black leaf on a Peace lily after propagating is not uncommon. The main reasons for this are under-zealous watering or over-fertilizing. Remember to keep the soil of your propagated plant moist and not soggy just as I have advised for a parent Peace lily plant. 

I don’t recommend fertilizing newly propagated Peace lilies for at least the first 2 months after taking the cutting. If you have used new potting soil to plant your propagated plant then it will have sufficient nutrients for roots to get thoroughly established.  

Black Leaves On Peace Lily After Re-Potting

The process of repotting is pretty similar to propagating with the only difference being that the entire peace lily is moved intact into a new home.

If your leaves are turning black, it may be due to the fact you added fertilizer too early: the newly replanted peace lily also needs a 2 month’s wait before it is fed.

Pruning A Peace Lily 

Peace lily blooms last for about 4 – 8 weeks. Following that period, they darken and wilt. At that point, you will need to prune them close to the base. Doing so will enable your peace lily to be able to sprout new flowers.

Wilted or broken leaves must also be pruned as well to reduce stress on the plant and enable it to direct its resources to healthier growth.

Removing Black Leaves From A Peace Lily

Blackened leaves need to be pruned right away. Since there might be a risk of infection, your pruning shears will benefit from a dip in disinfectant after each removal. Once you’re through there’ll be room for new growth to beautify your plant.

Final Thoughts On Peace Lily Leaves Turning Black

If your Peace lily’s leaves are turning black, consider which one of the following could be to blame: drought stress, overwatering, high temperatures, low humidity, direct exposure to sunlight, or use of water containing chlorine.

Maintaining the right balance of plant care by taking all the above factors into account and regularly inspecting your plant can enhance its quality of life and keep those leaves verdant and shiny for longer.