Overwatered cheeseplant with yellowing leaves, sitting in stagnant water
We are entering into winter (I live in Switzerland) and I overwatered my cheese plant (6 ft tall). Its leaves are yellowing at the bottom, the top leaves are still healthy. I have emptied the water but am concerned about the stagnant water (rotting smell). Should I repot and try to get rid of the rotted roots? Or leave it and let it recover on its own? Thanks in advance.
Rotted roots are sure death for any plant. If you can smell that stagnant smell, they're rotted. The only hope is to pull it out of the pot (you'll need to cut it back to compensate for the root loss, also to make it easier to handle, but you can root the cuttings,) wash off all the infected soil, cut off all the mushy roots, and replant in fresh soil (I like to use a 50-50 mix of cactus potting soil and perlite.) You can treat the roots with anti-fungal powder, which is pretty expensive if you have only a few plants, but you can sprinkle them with cinnamon before you repot - much cheaper, and possibly just as effective. Here are a couple of articles that have some more tips for you:
In the future, if you test the soil moisture all the way to the bottom of the pot, you can avoid overwatering.