9 Causes of Brown Peace Lily Leaves and How to Fix it

If you’re like me, you probably love the look of a green and healthy peace lily plant. But, one thing about this pretty plant that could frustrate you is seeing their leaves often turning brown. When it happened to me, I used to think it was because I wasn’t watering them enough, but I was wrong.

I researched several causes of brown leaves on a peace lily and found that some are easy to fix, while others are more difficult. So, let’s find out why peace lily leaves turn brown—and how to treat them.

Causes And Treatment Of Peace Lily Leaves Turning Brown

Peace Lily Leaves

Here are several causes and treatments of peace lily leaves turning brown

1. Lack of Water

The number one reason peace lily leaves turn brown is the lack of water. If you’re not watering your plant enough, the leaves will droop and eventually turn brown.

How to Treat:

The best way to water a peace lily is to soak the soil until it’s wet all the way through, then let it drain for a few minutes. You’ll need to do this at least once a week during the summer and every other winter.

Too Much Direct Sunlight

Light is essential for plants to grow, but too much of a good thing can be unhealthy. Peace lilies are sensitive to direct sunlight, which can cause their leaves to turn brown. This is because the leaves need time to rest and regenerate, and too much sunlight can prevent them from doing so.

How to Treat:

If you’re seeing brown leaves on your peace lily, the best thing to do is move it to a shadier spot. If that’s not possible, you can use a sheer curtain or greenhouse glass to diffuse the light.

2. Temperature Changes

One of the most common reasons leaves turn brown is temperature changes. If your home is too cold, the plant will try to conserve energy by dropping its leaves. If it’s too hot, the plant will do the same thing.

How to Treat:

The easiest way to prevent this is to keep your home’s temperature consistent. Consider also the humidity level in your home. Dry air can also cause leaves to turn brown, so increase the humidity level by using a humidifier or placing your plant near a water source.

3. Over-Fertilizing

One of the most common reasons for brown peace lily leaves is over-fertilization. When you fertilize your plant, you’re giving it a “shot” of nutrients it can use to grow. But if you fertilize too often or use too much fertilizer, you can burn the peace lily’s leaves. The brown patches on the leaves are a sign of this burn.

How to Treat:

If you are over-fertilizing your peace lily, the best thing to do is to flush the potting mix with clean water, which will help eliminate any excess fertilizer in the pot. Once you’ve done that, cut back on how often you fertilize, and use a diluted fertilizer when you do.

4. Under-Fertilizing

If you think your plant looks a little sad and you are unsure why it is; it might be because it needs more fertilizer. Peace lilies are heavy feeders, so they need to be fertilized regularly—about once a month during the growing season, which is spring and summer.

If you haven’t been fertilizing your peace lily, that could be the reason its leaves are turning brown.

How to Treat:

The good news is that it’s an easy fix—start fertilizing! I like to use a general-purpose fertilizer with a ratio of about 10-10-10.

When you fertilize, be sure to do it in moderation. Too much fertilizer can burn your plant roots, causing the leaves to turn brown. So give it a little each month, and you should see a difference in no time.

5. Repotting Stress

Your peace lily might experience brown leaves simply because it’s time for a new pot.

Now, you can go out and buy a brand-new pot every year. But if your peace lily is getting too big for its pot, it’s probably time to size up.

How to Treat:

When you re-pot your peace lily, use fresh potting soil and give the roots plenty of room to spread out. And if you’re unsure how to re-pot a peace lily, there are plenty of helpful videos online. Just give it a search.

Also, when you water your peace lily after repotting, be sure to do it with room-temperature water—cold water can shock the roots and cause brown leaves.

6. Poor Drainage

If your peace lily has poor drainage, the roots will start to rot, and this will cause the leaves to turn brown and die.

How to Treat:

To fix this, you must re-pot your plant in fresh potting mix and ensure that the pot has drainage holes in the bottom.

You can also improve drainage by adding perlite or vermiculite to the potting mix. And if you live in an area with hard water, try using distilled water or rainwater to water your peace lily.

7. Pests

If you see brown spots on your peace lily leaves, it’s likely because of pests. The most common pests that attack peace lilies are aphids, mealybugs, whiteflies, and spider mites. These pests are attracted to the plant because of the sweet sap from the leaves.

How to Treat:

To get rid of pests, start by spraying the plant with water to knock the pests off. Then, use a cotton swab dipped in rubbing alcohol to remove any remaining pests. You can also use an insecticidal soap or neem oil to get rid of the pests.

If you see any webbing on the leaves, that’s a sure sign of spider mites. To get rid of spider mites, spray the plant with water every few days and increase the humidity around the plant. You can also try using a miticide, but follow the instructions on the label carefully.

8. Diseases

If your peace lily has brown leaves, it could also be due to a disease. Unfortunately, quite a few of them can affect this type of plant.

Fungal diseases are the most common, often caused by too much moisture. If you notice brown spots on the leaves, that’s a sign of a fungal disease called Alternaria. Another one to watch out for is called Colletotrichum. They both manifest as brown lesions on the leaves.

Bacterial diseases can also cause the browning of the peace lily leaves. One of the most common is pseudomonas, which causes leaf spots and can lead to leaf drops. Erwinia is another bacteria that can affect peace lilies, causing the leaves to turn black and eventually die.

How to Treat:

If you think your peace lily has a disease, you can take it to a professional for diagnosis and treatment.

9. Older Leaves

The leaves on a peace lily are not all the same age; the ones at the bottom are older, and the ones at the top are newer. And as people get older, they will not look as good as they did when they were young.

So if you see some older leaves turning brown, it’s not necessarily a reason to panic. It’s just a part of the plant’s life cycle. However, if all the leaves are brown, that’s a different story. You should investigate further.

In conclusion, there are various reasons peace lily leaves may turn brown. However, it is often possible to save the plant by paying close attention to it and taking appropriate action. It is even better if you take preventive measures in tending to your plant than corrective. If you have unanswered and very concerning questions about your peace lily, speak with a professional.

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