2/3 of my tomato plants have a bottom leaf turning yellow, I read info online and it says it can be anything from underwatering, overwatering, fungi, lack of oxygen so confusing. I just transferred them to a bigger pot a couple days ago added 2/3 potting soil with 1/3 coco coir, I added 2-5-3 fertilizer (jobes organics vegtable and tomato) and mulched the top with coco coir (the leaf was yellow before) will it bounce back or can I cut off the leaf?