A friend of mine has a couple of peace lilies (Spathiphyllum) which she had purchased for her place of business several months ago. They had both done fine until a few weeks ago, when the ends of some of the leaves began turning yellow and brown, with pieces looking as though they were being eaten away on the edges. She mentioned that she was about to apply some insecticide and fungicide to treat the plants.
I told her to wait a minute. Although it is true that many plant problems can be caused by a fungus, bacteria, virus, or insect infestation, there is a fifth category of problems that one should look for first. Culture (physiological) culprits include too much watering, not enough watering, too much sun, not enough sun, too much or too little fertilizer, and the like. These are problems that can be rectified by simply modifying something in the plant's environment.
Since over-watering (too many salts accumulate at leaf ends) and under-watering (not enough nutrients get to leaf ends) of this plant produce similar aforementioned symptoms, I quizzed my friend n her watering routine. She said that she normally watered it twice a week, but admitted to being out of town for a while and watering it quite a bit extra upon her return.
Gently lifting one plant out of its pot, we found the roots to be long and white and healthy, as healthy roots should be, not the yellowish-brown mushiness that is characteristic of root rot. This was good. We placed the plant back in the pot and pruned off some of the unsightly leaves. My friend resolved not to let the soil dry out again and to keep it moist without becoming too damp or soggy. I stopped by again recently, and it looks as if she has saved both her plants and her money.
Robert Leffingwell, Smith County Master Gardener
Texas Cooperative Extension
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