Jack Herer seedlings about 3 weeks old.
Indoor, LED light, no watering just dome misting, around 26 deg Celsius.
Soil seed raising/cutting mix together with perlite ~40%
Lower leaves going yellow, one of them has black spot developing (red arrow).
In fact cotyledons gone brown & died a while ago.
But upper leaves still growing new ones.
What could the issue be?
Should I trim off the crappy looking leaves?