A word on spots....Keep in mind this is general and not specific to any one
plant.
If the spots or patches are crisp and brown, underwatering is the most likely cause.
If the areas are soft and dark brown, it is likely caused by overwatering.
If the spots or patches are white or straw colored, it is caused by watering with cold water, having water splash on the leaves, aerosol damage, or too much sun.
Various diseases can cause moist, blister like spots or dry and sunken spots as well.
Hope this helps
Barb
barbsblooms@shaw.ca