On one of my plants it's bad, and on another one it just starting. They began to yellow a few days ago, and now there's brown! Should I cut off the lower fan leaves?
I would worry about what the problem is thats causing them to yellow first.. I have had plants do this for a couple of reasons in the past. 1) not enough light on them when vedging. they need at least 100 watts 2) too much water. most seedlings only need watered every 3-5 days oncee they are this size(some go much longer) I'd look into those first, but honestly need more info on what your setup is to see if anyone can figure out whats deficient.
not enough info..whats the ph of your soil? what neuts are you using...whats the medium..how much light..temp ect...my guess would be ph or a N deficiency