Peace lilies are hardy plants, and they are pretty resilient to pests and problems, but sometimes, something will go wrong. If your peace lily leaves have started turning black for no apparent reason, you might be wondering what is wrong and what you can do about it. I’m going to walk you through this today.
There are quite a few potential causes of black leaves. The least concerning is that the foliage may be old, but black leaves can also be caused by pests, fungal infections, improper watering, and over-fertilization. Lack of humidity may also be an issue, and injuries from cold temperatures could cause black leaves.
The simplest and least worrying of the potential causes, old foliage may sometimes turn black. If only a small part of your plant seems to be affected and the rest of the leaf looks dull and tired, it may simply be old. Age usually only causes black tips, not entirely black leaves.
You can use sterile pruning shears to remove old foliage so that your plant focuses on new growth and continues to look aesthetically pleasing.
If your plant is under attack, it may respond to the stress with blackening leaves. Check under the leaves for signs of common peace lily predators, such as aphids, scale insects, mealybugs, and spider mites.
Isolate the plant and treat them using neem oil or soap and water if you find any of these. It is vital to get rid of plant predators quickly before they can do too much damage.
Unfortunately, this is a pretty common cause of leaf blackening, and it can be harder to deal with. Peace lilies like humidity, but they might start to suffer from fungal infections if you don’t get the balance right.
Usually, fungal infections will appear as spots on the leaves rather than at the tips. Some may have yellow centers, and others may create holes.
Please read up on the different kinds of fungal infections and compare them with the symptoms you are seeing. A fungal infection is a likely issue if you have overwatered or misted your peace lily too heavily, especially if it doesn’t get much airflow.
You may need to buy a commercial fungicide to deal with this. Some people mix baking soda with water and spray the affected areas, which may also help. Dry your plant out as much as you can without hurting it, and increase the airflow. Hopefully, you will be able to save it.
Too much water contributes to fungal issues, but it is also a source of stress on its own. If you aren’t paying attention to the wetness of your plant’s soil, you could easily overwater it. But, confusingly, underwatering might also cause stress and black leaves.
Check your plant’s soil before watering it. Unless it is dry or close to dry, please do not give it a drink. However, if it has started to wilt and the soil is dry, it is thirsty. This method helps prevent overwatering, reducing the risk of fungal infections, so it’s a double win.
Too Much Fertilizer
If you give your plant too much fertilizer, you will hamper its growth. Excess fertilizer will lead to a buildup of nitrogen in the soil and may make it far too acidic for the peace lily to cope with, which can lead to leaf blackening.
When the nutrients in the soil become too concentrated, they often become unavailable to the plant, which stunts its growth and makes it vulnerable to diseases.
If you have over-fertilized your plant, rinse the soil thoroughly with lots of water to remove the buildup. Then, put the plant somewhere to dry out, and don’t water it again for some time.
Lack Of Humidity
Peace lilies like humidity, and if you never mist your plant, its leaves may dry out and brown or blacken. Depending on where you are in the world, it’s a good idea to mist it once or twice a week, possibly more often in hot weather.
Mist in the morning to reduce the risk of fungal infections developing.
As rainforest plants, peace lilies dislike the cold, so keep them away from cold windowsills and freezing drafts. These will lead to cell damage that will blacken the leaves. Instead, the plant should be kept somewhere warm and stable.
There are many potential reasons for blackening leaves, but hopefully, you now know where to start. Work your way through the list, correcting each issue by turn, and your plant should be restored to full health before you know it.