Last week, I ordered 5 pieces of ZZ plants. It arrived somehow damaged (leaves yellowing and some have fallen off). The stem appeared to be undamaged. Today, however, I noticed that one of the ZZz stem appears to be rotting. It feels fleshy to the touch and some juice can be felt when pushed. All my other ZZ appears to have healthy stem. I potted them in a succulent mix added with some vermicast and pumice and still haven’t watered them. What should I do?
The number one cause of death for interior plants is over watering. That may or may not be true here but there are things you can do which will lower the risk:
- remove the white marble chips on the surface of the soil. They keep the soil moister longer and keeps moist soil in contact with the stems
- make sure there is drainage from the bottom of the pot. It's hard to tell from the picture but it looks like there is no tray to catch water that has drained to the bottom of the pot.
- increase the light levels by moving closer to a window
Most Zamia plants grown inside don't get a lot of light compared to outdoors and can do quite well if you let the top inch of soil dry out before watering. Wikipedia notes that it
can survive extremely well under interior low light levels for four months without water
I'm not sure I would wait that long between watering but too much is lethal.