Hey brothers and sisters ! This is my first grow s...

Hey There! So it's hard to tell what's going on with that one plant due to the led light. but it looks like it either one of two things. Which are it is either the normal part of its life were it will pull nitrogen from the lower bigger leaves to put it toward the bud sites or it is the start of a Cal-Mag deficiency but I cannot say for sure you would have to post a pic of it when its not under the led light need to see what it looks like. If It is only on the lower growth and no new/actively growing spots are being affected hopefully it is just the natural part of it's life. That is all I can really tell ya for now if you can throw up a pic without the led light on it should be able to help out more👍 Happy Growing!🙏