Not sure of what grow medium you are using.. When I soil grow, I wait until the pot is light - as in dry and not so heavy before I water again. If I pick up a pot and it's heavy, then I know it isn't the time to water. The down side being that if you wait to long, your plants will start to droop. Nothing a quick watering wont take care of. I never used MG out side of growing tomatoes so I am not able to say if you are feeding to much or to little. Just be aware if your lower leaves start turning blotchy yellow, you need to flush with clean water and let plant recover for a week before feeding a reduced diet again... Autos tend to turn yellow on the bottom fan leaves anyways but it is uniformed and on the entire leaf.. This is natural. It's when it is blotchy that you have a problem with nute-burn.