A Nitrogen deficiency will begin at the bottom of a plant and progress upwards in time , your lower leaves still look green , and the most deficient nutrient besides Nitrogen shown is Magnesium as its tie dyed looks indicate such as well as the necrosis beginning on the leaf tips due too pH , it actually could be the begining of a lockout but on the lower end , dont listen to those who say the Ph is high , the leaves would twist and contort and Iron deficiency would be very obvious with no color in the growing tips if the Ph was over 7.5 .. Drop below 6.2 with that soil and its low end lockout ... I think your Ph is right around 6.2 by looking and if it continues to drop the roots and leaves will burn and die in no time at all
I would make sure to maintain a proper Ph and see if you can get a reading of your soil , Miracle Grow Soils are known for there poor quality .. Might want to avoid using such in the future and youll see less of this issue ..
I say you have time to get them back on track but youll need to add feed and maintain a proper Ph to allow the plants to uptake nutrients as its obvious your soil has nutrients but the plants are not taking them up at this time , hence the begining of a lower end lockout ....