Very strange. If you are sure the soil is not too dry I wonder if it could be staying too soggy wet. Both extremes are damaging to roots and can cause such symptoms. Take care not to over feed the plants as fertilizer can burn roots and cause leaf browning along the tips and edges.
I suggest you take a sample to your County Extension Office and see if they can identify the problem and if necessary prescribe an appropriate remedy. Their contact info is:
Lake County Extension
1951 Woodlea Road
Tavares, FL 32778
Phone: (352) 343-4101
Thanks for the question. Please stop in again soon!
Q&A Library Searching Tips