My mother has two potted peace lilies and both are experiencing black curling leaves. She has had them both for about six months and were only repotted from the store container to her own. They have both bloomed in the past and are just now getting the black leaves. Can you tell us what might be causing this and if she can save her plants. Not all of the leaves are affected.
Black leaves are usually a good indication of root damage. With Peace Lilies, the most common cause of root damage is root rot, which in turn is caused when the soil around the roots does not dry out sufficiently between waterings.
This may be related to the repotting that was done 6 months ago. I don’t know the details of the repotting, but few people know how to do it properly. It is quite possible that some of the tiny root hairs were damaged during the repotting. In addition, the added soil absorbs and retains water for a long time and keeps the soil and roots from drying out frequently enough. This is particularly true if the new pot is larger than the old one.
There is not much you can do about the repotting at this point. However, you can control the watering. No water should be added until the leaves start to wilt just a bit. Then, add just enough water so that the plant reaches the wilt point again in about a week.
If there is no drainage hole in the new pot, then the accumulation of water in the bottom of the pot could be a serious problem.
Make sure the Peace Lilies are protected from direct rays of the sun, but otherwise as much indirect sunlight as possible.