I grew this croton for a long time and it was beautiful. Recently due to the cold weather, it dropped leaves as shown. However, I have also noticed that there are many white small hollow shells in the soil. When you squeeze it, it is broken and empty inside.
Is this a disease? What shall I do?
Certified GKH Gardening Expert
Those are slow release fertilizer pellets. It would be best to repot into a larger pot, and add more to it when you do. Here is an article that will give you more information on their care: https://www.gardeningknowhow.com/houseplants/croton/care-croton-plants.htm