I think the houseplant most commonly affected by soft rot is the jade plant. In the winter, stems become weak, then mushy then rot. This occurs because your plant has caught a bacterial infection. Any plant can be a victim.
Although over watering is blamed as the cause; the problem is really a lack of light. The rest of the year the water you put in the soil gets used and evaporated. During the winter the plant slows its grow and there isn’t much sun to speed up water evaporation. So by watering less in the winter, or giving the plant more light or both you can avoid the problem.
Two things need to be done once soft rot occurs. First you need to unpot the plant and put it in a new pot with fresh soil. If you must reuse the pot, run it through the dishwasher or scrub it down with bleach first and rinse thoroughly. You need to get rid of all the bacteria.
Next you must perform an amputation on the plant.Â Wipe the outside of the plant down with alcohol. Take a very sharp razor and sterilize it. Slice off the part of the plant effected plus some of the unaffected area below the rot. The bacteria spreads out before symptoms show. You must remove all the bacteria with out spreading it to the section that doesn’t have any bacteria.