Black spots?

Definitely not deficient at this stage in the game, the soil could be a little hot for it but first id check the ph of soil and make sure youre checking ph of your water too, it should be around 6.2 for soil. It really looks like the soil may have compacted and the roots may not be getting much air. Roots need oxygen to live and to keep things like root rot to a minimum. Hope this helps some, good luck!