Hudler, I hope someone is able to help you but I suspect if the plants were yellowing before they were planted they were not in good shape to start with. It would help if we knew where you are located. Different parts of the country have different problems and solutions. If you go to the little blue person in the upper right hand corner of your screen that is your profile and you can add an area.
Some don't want to be too specific and that is Ok but a general vicinity is very helpful.