IMHO,, by the looks of the plants,, you maybe over watering. My biggest piece of advice,, would be to let it dry out before watering. Your in containers,, so it will be very easy to tell when to water. Get used to feeling the weight of the plant and container. That will be a good indication of when to water. When not allowing the plants to dry out abit between waterings,, you are asking for big problems.