My brother-in-law is infamous for overwatering the houseplants (I had to rescue his spider plant), but he insists he's been watering the Chinese Evergreen the same way throughout all of it's ten years, and lately several leaves turned brown in the center. They're not dry, still soft, but look like this--anyone have a diagnosis to offer? It could probably use repotting, as the pot looks rather small, but that wouldn't cause this, would it?
It might help if you posted some pictures of the whole plant. That being said...how long has it been since the plant was repotted? After a while salts tend to build up in the soil and that can cause browning leaves. Often though that starts on the tips. Even if it doesn't need a bigger pot, getting some fresh soil every now and then is beneficial.
I didn't have my camera with me at their house, so I plucked off a leaf to take home and photograpy, lol! I will be back there later this week, so will bring the camera. A lot of the leaves look this way. It has been a long time since it was repotted. Thanks for the tip!
Oh, I know, I accidentally cooked some mint cuttings in the car recently, and I mean literally cooked--I was so mad at me! But this plant lives in an air conditioned house and never gets direct sunlight.
I wonder, if over the 10 years he's had the plant, he does the drought/flood watering cycle, and now that the plant is underpotted, it's become too dry more quickly--if he used to water it weekly and it was fine, an underpotted plant might need watered 2-3 times a week to stay as moist. I also wonder about temperature changes and cold drafts on the plant if he has it near an AC vent. These plants don't tolerate cold well, IME.
If it's really rootbound from being in the pot for a really long time it can become next to impossible to water a plant enough because there's so little soil to hold water relative to the amount of roots trying to take up water. So I wouldn't necessarily rule that one out.
Has anything else changed recently--moved it to a different area of the house, etc? When a plant's been going strong for a really long time and then all of a sudden starts to have problems I would always think about what might have changed recently.
That's a leaf from a plant that went south FAST. There are no conspicuous necrotic leaf tips or margins to suggest a gradual reduction in the water supply to the leaf due to chronic under-watering or a high level of soluble salts in the soil, and there is no evidence to suggest insects or disease. With these major possibilities eliminated as likely causes, odds greatly favor the underlying cause to be over-watering with the direct cause very likely being an infection of the fungus pythium splendens, which most often causes crown rot in this plant and the symptoms described.