Zero nitrogen fertilizer

Have a small food plot in clover I planted last fall. Was going to fertilize it with zero nitrogen. I bought potash in 50lb bags at the local co-op, but the did not have phosphate (TCP)available in bags - just bulk. Any ideas on where to acquire some? Obviously, the big box stores aren't a help. Nor is Tractor Supply.


FYI, my property is in the Dothan, AL area.