You definitely shouldn’t have this much yellowing this early. Not natural life cycle. I agree with GroBuddy above. Do you use the same nutes each feeding and the same amount each time? What are you feeding them? How often do you feed? How much do you feed them? Are you consistent with feeding? Do you check your ph each and every time you feed? What ph are you using, ie, 6.0 ? Develop you a consistent feed schedule with consistent ph readings and you shouldn’t see this again. IMHO ✌ï¸