When growing in soil you water your plant and then allow it dry out quite a bit before watering again. Depending on how big your plants and pots are, and perhaps some other factors, you shouldn't have to water more than twice a week. DO NOT water them everyday! The general rule of thumb is to let the top 2-3 inches of the soil dry out before watering. You can stick your finger in the soil and check it like that, or you can use a moisture meter. Before using the moisture meter clean the tip of the metal probe with a green scouring pad. Make sure the meter reads 10 on a scale of 1-10 when you place it in a bowl of water. If it reads 10 then your meter will give you an accurate reading.
This problem is easy to correct; stop over-watering it. It's that simple.
