Q.Dracaena
The stem of my Dracaena is becoming black. What’s wrong with it? Am I doing something wrong?
Generally the leaves of the plant will show signs of distress before it reaches the stem of the plant.
Do much direct light can cause the leaf tips to turn black.
Your Dracaena needs evenly moist soil but never soggy. If the roots sit in soggy, poorly draining soil they can suffer root rot. The leaves may turn brown or black and if the condition is not corrected, the stem may darken and die off.
Salts for conditioned water or excess fertilizer can build up and harm the plant.
Your plant could also be suffering from a fungus called Fusarium leaf wilt.
Applying a soil fungicide treatment can help.
Make sure you do not wet the leaves when you are watering.
https://www.gardeningknowhow.com/houseplants/dracaena/dracaena-houseplant-care.htm