I'd say Over-Fert, but I just got saved in another thread in this forum so what do I know.

Nut Disorder Link


The soil may be hot for a little plant, or there could be some lockout issues. I'd try flushing it with PH adusted water (adjusted to 6.5 - 7.0) and giving it some time. These things have a way of looking like nothing's happening for a few days and then BOOM! It takes off.