10 Reasons Your Peace Lily Leaves Are Turning Black (With Fixes)

Peace lily leaves can sometimes turn black, seemingly out of the blue. While it may at first look purely cosmetic, and of course it does make them look worse, it’s also a sign that something is wrong with how you’re caring for your plant.

Which can be a worry or disappointing. Understandably you want your peace lily to be as healthy as possible and looking it’s best.

So let’s go through the common causes for black leaves and the steps you can take to fix what’s going on.

1. Overwatering

The Problem:

Overwatering is the most common reason for black leaves (and most problems with peace lilies). When the soil is too wet it means the the roots can’t get the oxygen they need.

This will lead to the roots rotting and not being able to give then plant the nutrients it needs. And then the leaves react forbid by turning yellow, brown or black.

Signs of Overwatering:

The Fix:

1. Check Soil Moisture Regularly: Put your finger in the soil and feel to see how damp it is. You should only be watering when the top feels dry.
2. Proper Drainage: The pot your peace lily is in needs to have enough drainage holes. If it doesn’t then move it in to one that does.
3. Improve Soil Mix: Use a mix that drains well and contains the likes of peat moss, perlite and maybe a little bit of sand.

Emergency Measures: If you find root rot:

• Remove the plant from it’s pot.
• Trim away any mushy, dark roots.
• Repot it in fresh and dry soil. Then over the next few weeks you should water it less.

2. Underwatering

The Problem:

Peace lilies can deal with a bit of neglect if you don’t water them enough it will cause stress. If the soup is dry for too long your peace lily will take moisture from it’s leaves and they will then turn brown or black (usually starting at the tips).

Signs of Underwatering:

• The edges of the leaves curl and turn crispy.
• The soil becomes so dry it pulls way at the edges of the pot.
• Drooping leaves that look better once watered.

The Fix:

1. Rehydrate Slowly: Don’t go overboard with watering straightaway. Try to add small amounts of water slowly over time until you’ve got the soil moist again.
2. Water Consistently: Check the soil every 3 to 4 days and water when the soil feels dry to the touch.
3. Bottom Watering Method: You can put the pot in a tray of water for 15 to 20 minutes and let the roots soak up moisture to help.

3. Water Quality Issues

The Problem:

Peace lilies are sensitive to chemicals, many of which are found in tap water. The likes of chlorine and fluoride, for example. When these chemicals build up in the soil it an cause black spots on the leaves.

Signs of Water Quality Issues:

• Black or brown edges on leaves that are otherwise healthy.
• A white film on the surface of the soil.

The Fix:

1. Switch to Filtered or Distilled Water: Avoid tap water entirely if possible.
2. Allow Tap Water to Sit: If you don’t have access to filtered water then let your tap water sit out for about 24 hours as it will let the chemicals evaporate.
3. Flush the Soil: From time to time you can rinse the soil with distilled water as it will remove the chemicals that have built up.

4. Fungal Infections

The Problem:

If your peace lily is in high humidity and you overwater it you run the risk of fungi growing. There are certain diseases, like Cercospora and Phyllosticta, will show up as black or brown spots and can potentially cause the leaf to die.

Signs of Fungal Infections:

• Black or brown circle spots on the leaves.
• Yellow the edges on the spots.
• Spots that continue to spread even when you’re caring for your peace lily properly.

The Fix:

1. Remove Infected Leaves: Prune the affected leaves so it doesn’t spread.
2. Apply Fungicide: Use a fungicide for houseplants and make sure you follow the instructions found on the box or packaging.
3. Control Humidity: Reduce the humidity levels around your peace lily and give it enough ventilation.

5. Root Rot

The Problem:

As we looked at earlier, root rot is caused by overwatering. When the rot sets in the roots begin to decay and the plant can’t take up nutrients and water it needs. This will lead to major problems including black leaves.

Signs of Root Rot:

• Slow growth.
• Nasty smelling roots.
• Black or mushy tips of the roots.

The Fix:

1. Inspect the Roots: Take the plant out of its pot and check if the roots are healthy. If there are any black or mushy roots then cut those away.
2. Repot in Fresh Soil: Get a new and clean pot that has enough drainage and use fresh soil.

6. Pest Infestations

The Problem:

Pests like spider mites, aphids and mealybugs can make your peace lily weaker and cause black spots.

Signs of Pest Infestations:

• A sticky substance on the leaves.
• Bugs or webbing you can see on the plant.
• Curled leaves.

The Fix:

1. Wipe Leaves: Get rid of the pests by cleaning the leaves with a cloth.
2. Apply Neem Oil: Spray your peace lily with neem oil or an insecticidal soap. You should be focusing on the undersides of the leaves.
3. Isolate the Plant: Take the affected peace lily and keep it away from any other plants you have so the pests can’t spread.

7. Overfertilization

The Problem:

If you give your peace lily too much fertilizer it can result in salt building up in the soil. This can lead to the chemicals burning the roots.

Signs of Overfertilization:

• The edges of leaves turning black.
• Growing slowly even with lots of feeding.
• Crusty film on the top of the soil.

The Fix:

1. Flush the Soil: Water your peace lily and let the excess water drain away and it will help to wash the salts out with it.
2. Adjust Feeding Schedule: Feed every 4 to 6 weeks in the summer growing season. Use a balanced fertilizer.
3. Use Organic Fertilizers: A more gentle and natural fertilizer will be better for avoiding any issues. Something like compost tea works well.

8. Temperature Stress

The Problem:

Peace lilies don’t like the extreme temperatures. Too hot or too cold will cause big problems. The dry air especially can damage the leaves and make them turn black.

Signs of Temperature Stress:

• Tips of leaves that are near to windows or vents turning black.
• Suddenly notice a change in color after a rise or drop in temperature.

The Fix:

1. Maintain Ideal Temperatures: Keep the plant in a room where the temperature doesn’t change much. Somewhere between 65 to 80°F (18 to 27°C).
2. Protect from Drafts: If your peace lily is near a heater, air conditioner or drafty window then move it somewhere else.

9. Humidity Problems

The Problem:

If the humidity indoors is low it can cause the edges of the leaves to dry out and turn black. Peace lilies do best in higher humidity.

Signs of Low Humidity:

• Black tips and edges.
• Curled leaves.

The Fix:

1. Use a Humidifier: Put a humidifier near your peace lily. It will help keep the levels above 50%.
2. Create a Humidity Tray: Put a tray filled with water and pebbles under your pot. But don’t let the base of the pot get submerged as it can also cause root rot.

10. Aging Leaves

The Problem:

If your peace lily is older then any black leaves could simply be natural aging.

Signs of Aging:

• Black or yellow leaves at the bottom of the plant.
• Newer leaves growing normally.

The Fix:

1. Prune Regularly: Trim away any of the old and blackened leaves. It will keep the plant looking healthy and fresh.
2. Encourage New Growth: Make sure your peace lily is getting enough light and don’t over feed it.

Preventive Care Checklist

Final Thoughts

As long as you get to the problem early and do the right things to fix it there’s no reason black leaves have to permanent or terminal. Just figure out what is the cause and you shouldn’t have any problems acing your peace lily.