Hi BDT, first thought is that your growing medium is not really absorbing water. If parts of it get really dry it can take some doing to get it moistened again. Next time you water add a couple of drops of mild dish soap to the water to help it penetrate better. Also when you water add it slowly and water until you get runoff, check the weight of the pot before and after to be sure there is really a big weight difference. Happy growing
ps looks like there might be some calcium deficiency starting there. What are you feeding it and what is your pH?