My soils has developed areas where it is white and powdery in my garden outside. I am not sure what to do as it is spreading and not all plants are happy and appear to be rotting Really hope you can help and THANK YOU
It looks like white mold. You should check your plants to see if they have it, too. There is really no cure, you can try a fungicide, but I would just scoop it up off the soil and dispose of it in the trash.
https://www.gardeningknowhow.com/plant-problems/disease/white-mold-on-plants.htm