Certified GKH Gardening Expert
These are all symptoms of infection! This can happen with soils that, already, contain disease or that are too wet without a period to dry out.
I would treat with a fungicide. This article will help:
Be sure that the soil in all of these containers or areas have plenty of time to dry out down to, at least, 2 or 3 inches between watering. You may require a soil meter, or you can test with your finger.
Here is an article that will help you with testing soil moisture: