Wish I could see a picture of the actual mold. Are these plants grown outdoors? How is the soil moisture? If you say that your plants aren't overwatered, and they live indoors, then chances are you don't have a mold. If they live outside, and it may have been raining frequently, then you might have a mold. Aslo, you may want to check for bugs. If you notice aphids and/or ants, you may have a sooty mold. Do you notice any mold on the leaves? Need more info and pictures would help greatly.
Maulrat Reviewed by Maulrat on . Grey Mould Attacks! I'm growing three BigBud plants in pots outdoors here in the UK. Two of my plants have a covering of grey mould near the bottom of the plants where branches join the main stem. This has caused one (smaller) branch to begin wilting. I know the mould thrives in humid conditions so maybe its the damp air here in the UK of late? The lower canopy does have air getting to it so I'm not sure what I can do really. I have read that sodium bicarbonate applied to the area can help- is that a good plan? Rating: 5