It is not the lights as I’m using LEDs and maintaining 4inches separation.
latewood: I do not grow with LED lamps, but many around here do. It is my understanding that LED lamps can burn the crap out of your plants even though they do not appear hot. It is the light spectrum that burns the plant. 4" is way to close. Of course; The type of LED you have can make all the difference.
Don’t think it’s the soil as I used new sterile pots and soil for all the seeds and the others are doing fine.
latewood: Do you mean you are using sterile soil in thos sterile pots?
They did get dry one day - could this be it?
latewood: Could be. maybe
I just started fertilizing today with the high N - NPK fertilizer per your bible. What else should I do? Do I trim the brown? Leaves are still pretty small so not sure about trimming?
latewood: If you have an established root zone, add ing fertilizer is OK.
No need to trim a leaf until it is over 65-70% damaged.
Not sure about trimming; Don’t trim. Learn to grow a plant naturally, before trying advanced or inadvisable methods.
Next for you: Join our Support forum. Fill out this ILGM Support ticket I created just for you. 
Peace